Health Technology Review

Outpatient Parenteral Antibiotic Therapy

What Is the Issue?

• Outpatient parenteral antibiotic (or antimicrobial) therapy (OPAT) refers to the administration of IV antimicrobials outside of inpatient settings, without hospitalization. There are numerous delivery models, the most common being infusion centre–based, skilled nursing facility–based, and home-based.

• Evidence suggests OPAT is safe and effective for treating infections, reducing hospital stays, as well as lowering health care costs and improving patient flow. However, there is a need to evaluate the variability between different models of OPAT.

• There is variability between OPAT delivery models and their components. Therefore, it is important to examine these models of care to better understand how their outcomes compare. Decision-makers have requested evidence to inform decisions regarding OPAT delivery models and their components.

What Did We Do?

• To inform decisions on the use of different OPAT models for adult populations who require IV antimicrobials, we conducted a rapid review to summarize the evidence comparing the clinical and cost-effectiveness of OPAT to inpatient care, and different OPAT delivery models. We also sought to identify evidence-based guidelines regarding the use of OPAT for adults and models of OPAT care in Canada.

• We searched key resources, including journal citation databases, and conducted a focused internet search for relevant evidence published since 2018.

• The purpose of this report is to summarize and critically appraise the available evidence on the topic, but it does not provide formal recommendations on the implementation of OPAT. The report was externally reviewed by a clinical expert with experience in outpatient care and monitoring.

What Did We Find?

• We identified 3 studies conducted in Ontario and British Columbia that provided details about OPAT models of care in Canada. Two programs had OPAT rapid referral clinics, which were staffed with infectious diseases physicians and a nurse. One program was emergency department–facilitated and supervised by emergency department physicians and infectious diseases physicians on a part-time basis.

• We identified 1 health technology assessment, 3 systematic reviews, and 8 retrospective studies that showed that OPAT may be a safe and effective alternative option to inpatient care. However, findings were mixed and inconsistent. In studies that compared different OPAT models, self-administered OPAT appeared to be a safe and feasible alternative to health care–administered OPAT as well as to telemedicine-facilitated OPAT.

• However, the studies had several limitations, including being generally of low quality, which impacts the interpretation of their findings. There were statistically significant differences between treatment groups, meaning that patients who were systematically healthier were prescribed OPAT. Only 1 study was conducted in Canada, limiting the generalizability and applicability of findings in the Canadian context.

• Some studies included older adults and people who inject drugs; however, there were no studies that compared the clinical effectiveness of OPAT in these patient populations.

• No economic evaluations were identified, so the cost-effectiveness of OPAT compared to inpatient care and to different delivery models remains uncertain.

• Two guidelines were identified that consistently recommend the importance of a qualified infectious diseases professional as part of the OPAT team responsible for patient selection, treatment planning, and ongoing monitoring. The guidelines also recommend that there be a formal multidisciplinary OPAT team with clear governance structures. Regular follow-ups and ongoing monitoring are also recommended.

• The guidelines also recommend that older adults and people who inject drugs should not be excluded from OPAT and note that older adults can be considered for self-administered OPAT, with regular monitoring. One guideline also supports the use of telemedicine in home-based OPAT.

What Does This Mean?

• The quality of evidence was generally low and findings inconsistent across studies, thus limiting our confidence in the results.

• Findings were mixed and inconclusive, with no consistent differences in clinical outcomes and safety between OPAT and inpatient care. Self-administered OPAT showed similar effects on clinical outcomes compared to health care–administered OPAT. Likewise, evidence suggests that telemedicine-managed OPAT is a feasible option compared to conventional OPAT.

• Evidence suggests that patient selection is crucial for safe and effective OPAT across different delivery models.

• Decision-makers may wish to consider local resources, infrastructure, patient population, staffing capacity, availability of infectious disease specialists, and access to community-based services before OPAT implementation or expansion.

• Evidence describing models of OPAT care in Canada was limited, with details retrieved from metropolitan areas.

Research Questions

1. What models of outpatient parenteral antibiotic (or antimicrobial) therapy (OPAT) care exist across Canada?

2. What is the clinical effectiveness of OPAT compared to inpatient parenteral antibiotic (or antimicrobial) therapy (IPAT) and alternate OPAT delivery models?

3. What is the cost-effectiveness of OPAT compared to IPAT and alternate OPAT delivery models in Canada?

4. What are the evidence-based guidelines regarding the delivery of OPAT for adults that require antibiotic therapy?

Context and Policy Issues

OPAT refers to the administration of IV antibiotics on at least 2 days without being admitted to the hospital and without requiring hospitalization between treatments.¹ OPAT can be appropriate for treating both short-term conditions (e.g., cystitis, tonsillitis) and long-term infectious conditions (e.g., diabetic foot infection, infective endocarditis).² Individuals who may be eligible to receive OPAT include those who require ongoing treatment of complex infections but no longer require hospitalization and are not eligible for oral therapy.²

Components of OPAT programs generally consist of a formal multidisciplinary OPAT team, assessment of the patient's suitability and care requirements, and education on the OPAT treatment plan.^2-4 Components also include assessment by an infectious diseases (ID) specialist and pharmacist to identify patients eligible for oral therapy, as well as monitoring and communication between the patient and care team about treatment progress.^2-4 Lastly, programs typically include monitoring of the overall quality of care and outcomes, including hospital readmissions, complications, and adverse events.^2-4

What Are the Delivery Models?

There are numerous OPAT delivery models, each with their own advantages and disadvantages. Three of the most common models are infusion centre–based, skilled nursing facility–based, and home-based.^2-5

For infusion centre models, health care providers administer OPAT in outpatient health care facilities such as physicians’ offices, free-standing infusion centres, or extensions of acute care facilities.^2,5 Patients are not required to self-administer any treatment in this model; however, they must be able to access the infusion centre, which would likely require some travel.^2,5 This model may not be practical for individuals who require multiple antimicrobial doses per day.^2,5

In skilled nursing facility models, patients are admitted to a facility where onsite nurses administer antimicrobial infusions.^2,5 In this model, the nurses are also able to perform other related care activities such as wound care.^2,5 Given that this model is provided at a health care facility, patients may be at a higher risk of exposure to nosocomial pathogens (i.e., infections associated with patients receiving health care, like Clostridium difficile).^2,5

Home-based models of OPAT are carried out in the patient’s place of residence. OPAT is administered by either the patient, a care partner, or a home health nurse. In these models, patients do not need to travel to receive treatment but require a certain level of competency and comfort to self-administer treatment.^2,5

Why Is It Important to Do This Review?

Hospitals and inpatient settings are facing increasing capacity pressures. Outpatient treatment options may help alleviate this strain while maintaining high-quality patient care.^3,4 OPAT may have benefits for both patients and the health care system. Evidence suggests that OPAT can safely and effectively treat infection and improve patient satisfaction while also reducing hospital stays, which can lower health care costs and improve patient flow. However, there is variability between delivery models of OPAT.^3-5 Due to this variability, it is important to examine the models of care and their specific components to better understand how outcomes compare. Decision-makers have requested evidence to inform decisions regarding OPAT delivery models and their components.

Objectives

To support decision-making, we conducted a rapid review to summarize and critically appraise available evidence regarding clinical effectiveness, cost-effectiveness, and evidence-based guidelines about OPAT models of care. Additionally, we provide an overview of OPAT models in Canada identified in the literature.

Methods

An information specialist conducted a customized literature search, balancing comprehensiveness with relevancy, of multiple sources and grey literature on April 2, 2026.

One reviewer screened citations and selected studies based on the inclusion criteria presented in Table 1 and critically appraised included publications using 3 critical appraisal tools, depending on study design.^6-8 A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR 2) was used for systematic reviews (SRs) and the health technology assessment (HTA),⁶ the Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS) was used for nonrandomized studies,⁸ and the Appraisal of Guidelines for Research and Evaluation (AGREE II)⁷ was used to appraise guidelines.

Appendix 1 presents a detailed description of methods and selection criteria for included studies.

Table 1: Selection Criteria

CADD = continuous ambulatory delivery device; ED = emergency department; FTE = full-time equivalent; HTA = health technology assessment; ICER = incremental cost-effectiveness ratio; ICUR = incremental cost-utility ratio; IPAT = inpatient parenteral antibiotic (or antimicrobial) therapy; NA = not applicable; NRS = nonrandomized study; OPAT = outpatient parenteral antibiotic (or antimicrobial) therapy; PICC = peripherally inserted central catheter; QALY = quality-adjusted life-year; RCT = randomized controlled trial; SR = systematic review.

Summary of Evidence

Quantity of Research Available

This report includes 17 publications that met our inclusion criteria, including 1 HTA,⁹ 3 SRs,^10-12 11 nonrandomized studies,^13-20 and 2 guidelines.^1,21

• Three publications^22-24 (3 nonrandomized studies) addressed question 1.

• Twelve publications (1 HTA,⁹ 3 SRs,^10-12 8 nonrandomized studies) ^13-20 addressed question 2.

• Two publications (2 evidence-based guidelines)^1,21 addressed question 4.

No economic evaluations were found that addressed question 3. However, 2 nonrandomized studies^18,25 that did not meet our inclusion criteria but may provide relevant costing considerations are described in Appendix 6. Following completion of the literature search, a more recent edition²¹ of an included guideline²⁶ was identified that met the eligibility criteria. This publication was subsequently included in the report, despite being published after the search date. One HTA⁹ and 1 SR¹⁰ had broader inclusion criteria than this report. These publications included studies with both a pediatric and adult population. We reported on the characteristics and results from the subset of relevant studies that were only focused on adults who require IV antibiotics. Appendix 2 presents the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA)²⁷ flow chart of the study selection.

A detailed summary of study characteristics can be found in Appendix 3. Additional references of potential interest that did not meet the inclusion criteria are provided in Appendix 8.

Summary of Study Characteristics

We identified 3 studies that provide insights into the models of OPAT care in Canada, conducted in Ontario (2 studies) and British Columbia (1 study). We identified 12 publications, 1 HTA, 3 SRs with meta-analyses, and 8 retrospective cohort studies. Studies were conducted in Australia, Canada (1 study), Spain, the UK, and the US. All studies included adults who require prolonged IV antimicrobial therapy, with patients ranging in age from 18 to 92 years. A range of infections were represented, including bone and joint infections, osteomyelitis, urinary tract infections, and infective endocarditis. Several OPAT delivery models were represented, including those that were home-based, facility-based, telemedicine-managed, and community nurse–led. Two evidence-based guidelines were identified that were produced by the British Society of Antimicrobial Chemotherapy (BSAC) in the UK in 2026 and by the Infectious Diseases Society of America (IDSA) in the US in 2019. A detailed summary of study characteristics organized by research question can be found in Appendix 3.

Summary of Critical Appraisal

Overall, the HTA and SRs were of moderate quality. Strengths include the comprehensive search strategies, adequate reporting of the characteristics of included studies, and appropriate risk of bias assessments in the 3 SRs. In the 3 SRs that included a meta-analysis, appropriate methods were used for the statistical pooling of results;^10-12 however, there was heterogeneity between included studies. Key limitations include limited reporting regarding the establishment of review methods before the conduct of the review, limited details regarding data extraction,^9,12 and no justifications for the inclusion of specific study designs or exclusion of studies.^9,12

All nonrandomized studies were assessed as having a high risk of bias. Selection bias was the highest risk in all studies due to statistically significant differences in baseline characteristics as well as differences in patient selection between the treatment groups.^13,14 The risk of performance bias was rated low in each study because interventions and outcome measures were confirmed from trustworthy sources such as medical records or administrative databases. The risk of detection bias was also rated low or unclear in most studies. If blinding of outcome assessors was not conducted, objective outcomes were assessed, such as hospital readmission or death.^13,16-20 Attrition bias was reported as unclear in all studies, as it was not reported whether or not missing data affected outcomes. The risk of reporting bias was also low in all studies due to the fact that expected and previously determined relevant outcomes were fully reported.

Overall, the guidelines were of moderate quality. Strengths include clearly defined objectives, a multidisciplinary guideline development group, rigour of guideline development, as well as explicit links between recommendations and supporting evidence. Recommendations were also clear, specific, and unambiguous. However, only 1 group reported the quality of the evidence and the strength of recommendations.

A detailed summary of the critical appraisal, including details about strengths and limitations of the included publications, can be found in Appendix 4.

Summary of Findings

Question 1: Models of OPAT Care in Canada

Evidence regarding models of OPAT care in Canada was available from 3 nonrandomized studies.^22-24 Across studies, 2 centres²² had an OPAT clinic that works as a rapid referral clinic and 1 care centre had an OPAT being run by the emergency department (ED).²⁴ Details regarding operational and structural characteristics of OPAT programs were extracted from studies and not confirmed with OPAT programs via a questionnaire or consultation. Therefore, programs may have been updated or modified since the time of study publication.

The rapid referral clinics operate in Ontario at the Civic campus of The Ottawa Hospital and in Toronto at the Sunnybrook Health Sciences Centre.^22,23 The OPAT clinic at the Sunnybrook Health Sciences Centre operates during business hours 5 days a week.²² Both clinics receive referrals from the ED,²³ hospitalized patients that have been assessed by an inpatient ID consult, or other outpatient providers affiliated with the same institution (Sunnybrook Health Sciences Centre).²² ID physicians are staffed at both clinics, where they assess patients within 48 to 96 hours to determine the need for ongoing IV treatment,²³ review referrals,²² as well as arrange follow-up and outpatient monitoring. ²² Patients are then discharged home to receive either infusion at a community clinic,^22,23 by a home care nurse at home,^22,23 or trained by a nurse to self-administer treatment.²² At The Ottawa Hospital OPAT clinic, patients are discharged home with a peripheral IV line and an order for community IV antibiotics for 7 days. Whether or not a patient is prescribed an infusion of antibiotics at home or at a community clinic depends on the ability of the patient to travel. If a patient is able to travel, they are contacted via telephone to receive daily IV doses at a clinic near their home, and if they are not able to travel, they are assigned a home care nurse who administers IV antibiotics daily at the patient’s home.²³ Both clinics are also staffed with nurses:

• At the Civic campus of The Ottawa Hospital, 1 nurse works 3 half days on Monday, Wednesday, and Friday.²³

• At the Sunnybrook Health Sciences Centre, a specialist nurse (0.25 full-time equivalent) is employed and is often shared with other rapid referral clinics.²²

The OPAT clinic at the Sunnybrook Health Sciences Centre is also staffed with an administrative assistant.²² At the Sunnybrook Health Sciences Centre, the antimicrobials were coordinated and funded by Ontario Local Health Integration Networks (now Ontario Health).²² At The Ottawa Hospital, the choice of antimicrobials is at the discretion of the ED physician.²³

At Vancouver General Hospital in British Columbia, OPAT is facilitated and run by the ED. IV antibiotics are infused and received, usually once daily under the supervision of ED physicians. ED physicians are encouraged to refer patients to an ID physician after 5 days of treatment, but ultimately the decision to include an ID physician in patient care is at the discretion of the ED physician. During the study period, ID physicians were assigned to the OPAT program each week, Monday to Friday from 9:00 a.m. to 12:00 p.m. Outside those hours, ED physicians supervise the OPAT program.²⁴

Additional details can be found in Table 2.

Table 2: Models of OPAT Programs in Canada

ED = emergency department; ID = infectious diseases; NA = not applicable; OPAT = outpatient parenteral antimicrobial (or antimicrobial) therapy; SHSC = Sunnybrook Health Sciences Centre.

^aPatient characteristics of the cited study, which may not represent all patients seen by the OPAT program.

Question 2: Clinical Effectiveness of OPAT Compared to IPAT and Alternative OPAT Delivery Models

Appendix 5 presents additional details regarding the main study findings.

Evidence regarding the clinical effectiveness of OPAT compared to inpatient care was available from 5 studies (1 HTA, 1 SR, and 3 primary studies), and evidence of clinical effectiveness of alternative OPAT delivery models compared to each other was available from 8 studies (1 HTA, 2 SRs, and 5 primary studies)

Readmission

OPAT Versus Inpatient Care

Three studies compared the readmission of patients who received OPAT with those who received inpatient IV antibiotic treatment.^9,17,20 One study found that the 30-day readmission due to cellulitis was statistically significantly lower in patients with acute uncomplicated cellulitis (no major complications or comorbidities) who received OPAT compared to inpatient standard of care (in 0.5% versus 3.6% of patients, P = 0.02).¹⁷ One study found that there was no difference in 90-day readmission of any cause or due to adverse reactions (catheter- or drug-related) in patients with infective endocarditis who received OPAT or hospital-based antibiotic treatment.²⁰ One HTA found that evidence regarding the impact of OPAT on the hospital readmission of patients compared to inpatient treatment was inconclusive (some studies found OPAT superior, some found it inferior to inpatient care, and others showed no difference between the 2 delivery models).⁹ Results comparing specific OPAT delivery models and inpatient care were also mixed and inconclusive regarding the impact on hospital readmission:⁹

• Two studies that compared self-administered OPAT to inpatient treatment found no statistically significant difference between the 2.

• Two studies found that hospital readmission was statistically significantly lower in patients who received inpatient treatment versus patients who received district or community nurse–administered OPAT (i.e., OPAT was inferior to inpatient treatment).

• Studies comparing specialist OPAT nurse–administered OPAT to inpatient treatment were mixed and inconclusive, with 2 studies finding OPAT superior (hospital readmissions were statistically significantly lower with OPAT compared to inpatient treatment) and 1 study finding no statistically significant difference between delivery model and inpatient care.

Tele-OPAT Versus Conventional OPAT

Two studies compared OPAT managed with telemedicine to conventional OPAT without telemedicine. Telemedicine-managed OPAT can either be in the form of video or telephone consultations during the delivery of parenteral antibiotics in the patient’s home or in clinics. Telehealth can be facilitated calls by ID specialists for consultation or follow-up after hospital discharge. The SR that compared tele-OPAT to conventional OPAT found that patients receiving tele-OPAT had a statistically significantly lower risk of all-cause unplanned readmission compared to patients who received conventional OPAT. Another study compared OPAT managed by an ID physician via telehealth to patients who did not receive tele-OPAT. This study found that there was no statistically significant difference in readmissions for any cause or due to a complication between the 2 groups.

Home- Versus Facility-Based OPAT

One systematic review found that there was no statistically significant difference in readmission (30- and 90-day readmission, as well as readmission during the course of OPAT) between patients who received home-based OPAT compared to patients who received facility-based OPAT.

More details can be found in Table 10.

Clinical Cure

OPAT Versus Inpatient Care

One HTA found that evidence comparing OPAT to inpatient treatment was inconclusive regarding cure and improvement rates.⁹ Results comparing specific OPAT delivery models to inpatient treatment were also mixed and inconclusive:⁹

• A study comparing clinic-based OPAT versus inpatient treatment found that OPAT was inferior to inpatient treatment in improving infections.

• Three studies found that self-administered OPAT and specialist OPAT nurse–administered treatment were superior at cure and improvement rates compared to inpatient treatment.

• Two studies showed no difference between district or community nurse–administered OPAT and inpatient treatment on its impact on cure or improvement.

Self-Administered OPAT Versus Other OPAT Delivery Models

Two studies compared the clinical benefit of self-administered OPAT to other OPAT delivery models.^15,19 One study compared the cure rate, defined as no treatment failure during treatment or within 28 days of treatment completion, between self-administered OPAT and health care–administered OPAT. Results showed that there was a statistically significant difference in cure rates, with higher rates in patients who had self-administered OPAT (80% of patients prescribed health care–administered OPAT versus 91% of patients who were prescribed self-administered OPAT, P = 0.02).¹⁵ Another study assessed the factors associated with OPAT success, defined as completion of therapy with no change in antimicrobial agent, minimal or no adverse events, and improvement of infection.¹⁹ This study found that patients who received OPAT via OPAT clinics were statistically significantly associated with improved OPAT success compared to those who were prescribed self-administered OPAT (odds ratio = 2.1; 95% CI, 1.03 to 2.25; P = 0.02). There was no difference in likelihood of OPAT success between self-administered OPAT and community nurse–led OPAT.¹⁹

Additional details can be found in Table 14.

Harms: Adverse Events and Complications

OPAT Versus Inpatient Treatment

Three studies compared the harms associated with treatment between OPAT and inpatient treatment.^9,10,18 One SR and MA found that in adult participants there was no statistically significant difference in adverse drug reactions related to microbials or administration devices between OPAT and inpatient treatment.¹⁰ One HTA found that evidence on drug-related side effects or venous access complications was mixed, with some studies suggesting OPAT is superior at causing drug-related side effects (2 studies) and others finding no difference between the 2 (6 studies).⁹ One matched retrospective cohort study compared the incidence of composite adverse events within 90 days of initial hospital admission. Composite adverse events included acute kidney injury, venous thromboembolism, C. difficile diarrhea, neutropenia, unplanned hospital readmission, and death.¹⁸ Authors found that the risk of composite adverse outcomes was similar in both groups and there was no statistically significant difference in the risk of composite adverse events. When comparing the incidence of each adverse event between the 2 groups, there was no statistical difference between patients who received OPAT and IPAT in the risk of acute kidney injury, venous thromboembolism, and neutropenia.¹⁸ Patients who received OPAT had a statistically significant lower risk of developing C. difficile diarrhea than patients who received IPAT.¹⁸

Tele-OPAT Versus Conventional OPAT

One study found that there was no statistically significant difference in any OPAT complication or adverse drug reactions between ID telehealth–managed OPAT and non-ID telehealth–managed OPAT. However, this study also found that patients who received ID telehealth–managed OPAT had a statistically significant chance of getting a line-related complication compared to patients who did not have telehealth-managed OPAT.¹⁴

Health Care–Administered OPAT Versus Self-Administered OPAT

Four studies that compared self-administered OPAT to health care–administered OPAT found that there was no statistically significant difference in drug-, device-, or line-related adverse events.^9,13,15

Community-Led OPAT Versus OPAT Delivered Via Other Models (Hospital Wards, Clinics, Self-Administered)

One study compared the risk of developing complications in patients receiving community IV antibiotic service and OPAT delivered in other ways, such as in hospital wards or self-administered, and found no statistically significant difference between the models of OPAT delivery.¹⁶ Another study found that community nurse–led OPAT was associated with more OPAT-related adverse events compared to self-administered OPAT (no statistical analysis). This study also found that the patients who had self-administered OPAT had more OPAT-related adverse events compared to patients who had treatment in OPAT clinics.¹⁹

Additional details can be found in Table 11.

Mortality

OPAT Versus Inpatient Treatment

Four studies, including 1 SR,¹⁰1 HTA,⁹ and 2 retrospective cohort studies,^18,20 assessed the difference in mortality between OPAT and inpatient treatment. The SR found no difference in the risk of death in adults receiving IV antimicrobial treatment.¹⁰ The HTA found that the evidence was mixed, with 5 studies showing no difference in death and 1 study finding that OPAT is inferior to inpatient treatment in mortality.⁹ The 2 studies found that death was statistically significantly higher in patients that received IPAT (2% of patients receiving OPAT and 8.8% of patients receiving IPAT, adjusted P < 0.001)¹⁸ and hospital-based treatment (7.7% of patients receiving OPAT and 12.5% of patients receiving hospital-based treatment, P = 0.004) compared to those who received OPAT.²⁰

Tele-OPAT Versus Conventional OPAT

One study found that all-cause mortality was statistically significantly lower in patients who received ID telehealth-managed OPAT compared to patients who did not.¹⁴

Additional details can be found in Table 12.

Duration of Therapy

One SR found that there was no difference in the duration of antimicrobial treatment between patients who received OPAT and those who received inpatient treatment.¹⁰ One HTA found evidence that there is no difference in the days of therapy between OPAT and inpatient treatment (8 studies).⁹

Question 3: Cost-Effectiveness of OPAT Compared to IPAT and Alternative OPAT Delivery Models

No cost-effectiveness or cost-utility evaluations in the health systems in Canada were identified. Therefore, no summary can be provided.

Question 4: Recommendations Regarding the Delivery of OPAT

Detailed recommendations can be found in Table 16. The strength of recommendations and quality of evidence associated with recommendations are provided if they were reported by the guideline.

ID Physician Oversight and Involvement

BSAC recommends that a medically qualified ID clinician or specialist be included in the OPAT team.²¹ The strength of the recommendation and quality of evidence were not reported. BSAC also recommends that the inclusion and exclusion criteria for OPAT be created by an infection specialist.²¹ IDSA recommends that all patients be reviewed by an ID expert before the start of OPAT; this is a strong recommendation based on very low-quality evidence.¹

Telemedicine

BSAC recommends that OPAT services consider the role of telemedicine and remote monitoring for supporting patients who get OPAT at home.²¹

Delivery Model

Both BSAC and IDSA recommend that self-administered or caregiver-administered OPAT be considered for patients for whom it is appropriate, after education and with adequate support (IDSA: strong recommendation based on low-quality evidence).^1,21 BSAC recommends that training of patients and caregivers in IV administration comply with published standards and be carried out by a qualified member of the OPAT team.²¹ Likewise, IDSA notes that patients or caregivers can proceed without the need for a nurse visiting the home if there is a system in place for the monitoring of adverse events or complications (weak recommendation based on low-quality evidence).¹ BSAC recommends that patients and caregivers should be fully informed about the OPAT delivery model and be given the chance to accept or decline the model.²¹

IDSA and BSAC both recommend that the first dose of an antimicrobial be administered under the supervision of a health care professional (IDSA)¹ or competent personnel (BSAC)²¹ who can identify and respond to anaphylactic reactions. BSAC recommends that this can be in the person’s home³³ and IDSA recommends it can happen in the patient’s home, for patients with no prior history of antimicrobials that belong in the same class (weak recommendation based on very low-quality evidence).¹

OPAT for Older Adults, PWID, or People Who Are Unhoused

Older Adults

BSAC recommends that OPAT should be considered for “hard-to-reach” individuals, such as PWID or older adults, after an individual risk assessment. It also recommends collaboration of OPAT with community-based services or care providers such as services for substance use disorders or frailty to support treatment adherence and completion.²¹ IDSA also recommends that older adults be allowed to receive OPAT at home (strong recommendation based on low-quality evidence). IDSA noted that decisions about OPAT for PWID should be made on a case-by-case basis, but no recommendation was made because of low-quality evidence.¹

Vascular Access

BSAC recommends that the OPAT team be responsible for the choice of IV access, in collaboration with the referring team. It recommends that teams referring patients for OPAT liaise with the vascular access and OPAT teams before IV access is obtained.²¹

Medication Administration Devices

BSAC recommends that a member of the OPAT team with appropriate competency be responsible for selection of the drug delivery device. It recommends that antimicrobial agents should only be used in pumps or elastomeric devices if there is robust drug stability data that meets national standards and protocols.²¹

OPAT Team and Governance

BSAC recommends that OPAT be delivered within a formal OPAT service with clear governance structures^21,32,33 and clear managerial lines of responsibility.²¹ BSAC recommends that OPAT be delivered within a formal OPAT service with clear pathways for early discharge or admission avoidance.²¹ In addition, BSAC recommends that the OPAT team have an identifiable lead clinician and team.²¹

Follow-Up and Monitoring

Both groups provide recommendations for patient monitoring and follow-up tests.^1,21 BSAC recommends that OPAT teams develop protocols for monitoring patients, including frequency and type of blood test monitoring.21 Likewise, IDSA also notes that the treating physicians should dictate the frequency of office visits based on patient characteristics, nature of infection, patient tolerance, and response to therapy, as well as patient social factors.¹ BSAC recommends that patients have blood tests performed weekly, including full blood count and C-reactive protein. BSAC recommends that patients with skin and soft tissue infections be reviewed daily by the OPAT team to determine the transition to oral antibiotics.²¹ IDSA recommends that serial laboratory testing be monitored for patients receiving OPAT, although they cannot recommend specific tests or frequencies (strong recommendation based on high-quality evidence).¹

Limitations

Methodology and Engagement Approach

As the nature and scope of the request was focused on reviewing published clinical data, we did not conduct direct engagement with patients, caregivers, or providers. We also did not search for or include literature on perspectives, experiences, or other evidence relevant to underserved groups. This review therefore did not address patient and/or caregiver experiences with OPAT care and may not fully capture the benefits, challenges, and acceptability of OPAT and alternative OPAT delivery models. Because of this, we have missed including the lived and living experience of individuals who have limited access to OPAT (patients living in rural or remote areas) or who have historically been excluded from OPAT criteria (older adults or PWID). We acknowledge this as a limitation of our work and that this rapid review may not highlight or identify perspectives from and evidence related to these groups in Canada. We also recognize that the research team consists of settler researchers, and we come to this work with our individual privileges and biases. Understanding the perspectives and priorities of First Nations, Inuit, and Métis Peoples and other underserved groups in OPAT care can support informed health care decision-making.

Risk of Bias of Included Studies

All nonrandomized studies had a high risk of bias due to the fact that there were statistically significant differences in patient baseline characteristics between treatment groups.^13-20 Patients who were older, had more chronic conditions, or multiple comorbidities were assigned to OPAT models with greater health care professional involvement or inpatient IV administration.^13,18 Although this likely reflects how clinicians tailor treatments to patients’ clinical needs, these baseline differences may have influenced the observed outcomes. As a result, findings should be interpreted cautiously. Although some studies tried to minimize confounding,^16,18 in studies comparing OPAT with inpatient care, patients selected for OPAT were systematically healthier; therefore, this may have influenced the differences in outcomes compared to differences in the intervention. In addition, the SRs also included low-quality studies (i.e., conference abstracts, nonrandomized studies)¹¹ in their meta-analyses, which also warrant careful interpretation of findings.

Evidence Gaps

Although there is a high volume of literature regarding OPAT and the effectiveness of different OPAT delivery models, important gaps remain in the evidence base. There are limited high-quality RCTs or trials that report on the impacts of different OPAT delivery models on patients receiving IV antimicrobials in outpatient settings. In situations in which RCTs are not able to be conducted, well-designed nonrandomized studies, with matched cohorts for instance,¹⁸ are limited. In addition, there are limited studies that adjust and control confounders that can greatly impact outcomes, such as disease severity or comorbidities. Most studies identified had smaller sample sizes. Future studies with larger sample sizes that are adequately powered are needed to detect meaningful differences.

There is limited evidence available on the effectiveness of different delivery models for older adults, PWID, or populations that are unhoused. In our analysis, some studies had participants that fit these criteria, but results were not separated. In some instances, PWID were excluded from analysis. Therefore, it is unknown if findings can be generalized to these population groups. We identified guidelines^1,21 that recommend the prescription or consideration of OPAT for older adults, PWID, and people who are unhoused; however, the evidence base remains limited. We found 1 study that addressed OPAT in rural or small communities;¹⁴ however, studies that compare the effectiveness of different OPAT models in this setting would be useful to identify the most effective and feasible models.

Telemedicine-managed OPAT seems to be a viable option; however, there is limited moderate-to-high-quality evidence on the effectiveness or feasibility of the use of telemedicine in OPAT. In addition, 1 guideline, BSAC, provided recommendations about the use of telemedicine.²¹ If telemedicine were a viable option, OPAT teams would benefit from best practice considerations and recommendations regarding OPAT.

Although we identified studies conducted in Canada that compared the costs of OPAT and IPAT^18,25, we did not identify any cost-effectiveness or cost-utility analyses performed in Canada that compared OPAT with IPAT or evaluated the value of different OPAT delivery models.

Multiple studies assessed the impact of different OPAT delivery methods on hospital readmission, but very few assessed the impact of OPAT on ED visits. Therefore, we cannot draw conclusions on the impact of OPAT on ED diversion or ED utilization.

Generalizability

Only 1 study identified was conducted in Canada.¹⁸ Other studies were conducted in Australia, Spain, the UK, and the US. In addition, none of the guidelines were developed by groups in Canada, for use in Canada. Although the patient populations in the included studies may be relatively similar between other countries and Canada or across jurisdictions, crucial differences in demographics or health care systems limit the applicability of findings to Canada. For instance, there are differences between health system structures, funding models, availability of home care and infusion services, availability of infrastructure for OPAT, or access and availability of ID clinicians or consultants. In addition, there are also differences in OPAT delivery between jurisdictions, which may limit the applicability of the findings for the study conducted in British Columbia compared to other jurisdictions. For example, in British Columbia, ID physicians are incentivized to supervise OPAT, which may not be representative of practices in other jurisdictions.¹⁸ One nonrandomized study was included in our analysis that focused on the use of oritavancin in OPAT for patients with acute uncomplicated cellulitis.¹⁷ This drug was approved by Health Canada in September 2025, but it is unclear how it is marketed in Canada. Therefore, the findings from this study may have limited applicability to current clinical practice in Canada.

We also found 3 studies from 2 jurisdictions (Ontario and British Columbia) that described the model of OPAT care in Canada.^22-24 Information regarding models of care was available from 3 metropolitan areas, Ottawa, Toronto, and Vancouver. Therefore, this may not reflect care programs in smaller communities, rural or remote regions, or northern jurisdictions. Furthermore, access to OPAT may differ for populations that face barriers to health care, such as people living in remote regions; First Nations, Inuit, and Métis Peoples; PWID; and individuals with limited access to specialist care. We found some evidence in international contexts that addressed the impact of different delivery models in people who are underinsured¹³ or who live in small communities.¹⁴ However, findings should be interpreted with caution when applying them to the Canadian context.

Conclusions and Implications for Decision- or Policy-Making

This rapid review evaluated the literature regarding the clinical and cost-effectiveness of OPAT compared to IPAT and alternative OPAT delivery models for adults who require IV antimicrobials outside the hospital setting. This review also looked at the models of OPAT care in Canada and guidelines regarding OPAT. We identified 3 nonrandomized studies^22-24 for question 1; 1 HTA,⁹ 3 SRs,^10-12 and 8 nonrandomized studies for question 2; and 2 guidelines for question 4.^1,21 No relevant studies were identified for question 3.

Summary of Evidence

Models of OPAT Care in Canada

Evidence regarding the models of OPAT care in Canada was found for 2 jurisdictions, and 2 models were identified — rapid referral OPAT clinics^22,23 and ED-facilitated OPAT.²⁴ Infusion locations were the patient’s home (self- or health care professional–administered), clinics (including community-based), or the ED.^22-24 ID physicians are involved in all clinics. In 1 clinic, involvement of an ID physician is at the discretion of ED physicians.²⁴ In addition, the clinics are staffed by nurses and ED physicians who are responsible for OPAT supervision (British Columbia).²⁴ An administrative assistant is also staffed at 1 clinic. The rapid referral clinics received referrals from the ED,²³ hospitalized patients who have been assessed by an inpatient ID consult, or other outpatient providers.²²

Clinical Effectiveness

Findings were mixed and inconclusive, with no consistent differences demonstrated between OPAT and inpatient care regarding clinical outcomes or patient safety. Generally, the quality of evidence is low, and conclusions should be interpreted cautiously. Evidence regarding hospital readmissions was inconsistent, with some studies reporting that OPAT is associated with lower readmission rates, whereas others report no statistically significant differences between OPAT and inpatient care.^9,17,20 Likewise, evidence regarding mortality is also mixed, with some studies showing no difference in the risk of death between patients who received OPAT or inpatient treatment and some studies showing that the incidence of death was statistically significantly lower in patients prescribed OPAT compared to inpatient care.^9,10,18,20 Evidence regarding adverse events indicates that OPAT does not result in more harm than inpatient care.^9,10,18 Across studies, there was generally no difference in adverse events (drug- or device-related) or complications.^9,10,18 Some evidence suggests that OPAT may be a safe alternative to inpatient antimicrobial therapy for patients, but findings are mixed, and no definitive conclusions can be made. There was no difference in the duration of treatment between treatment groups.^9,10

Evidence comparing different OPAT delivery models was limited and heterogeneous. Findings suggest that telemedicine-managed OPAT is a feasible option that does not cause more harm to patients compared to conventional OPAT with no telemedicine.^11,14 However, findings were based on a small number of low-quality studies. One study showed no differences in the incidence of adverse events and mixed effects on hospital readmission; death was lower in patients who received tele-OPAT.¹⁴ In addition, self-administered OPAT was associated with clinical outcomes similar to health care–administered OPAT.^9,13,15 Some studies showed that there were similar rates of adverse events and higher treatment success compared to health care–administered OPAT.^9,13,15

Most studies were nonrandomized (even in SRs and the HTA) and retrospective in nature, with a high risk of selection bias and residual confounding. Patients who were prescribed OPAT were often systematically healthier and clinically stable to receive outpatient care compared to patients who remained hospitalized or treated by health care professionals. Therefore, findings should be interpreted with caution.

Cost-Effectiveness

No cost-effectiveness or cost-utility evaluations performed within the health systems in Canada were identified.

Evidence from 2 Canadian nonrandomized studies suggests that OPAT may have lower total health care costs per patient relative to IPAT ($7,394 lower per patient in Ottawa²⁵ and $17,579 lower per patient in British Columbia¹⁸); although OPAT costs remained higher ($651 per patient) than for patients receiving community-based IV antibiotics with return to the ED as needed in Ottawa.²⁵

Although these findings suggest that OPAT may be a less costly alternative to inpatient care, the evidence is limited to nonrandomized studies reporting costs only. Because no studies assessed cost-effectiveness or cost-utility by jointly considering costs and health outcomes, the overall economic value of OPAT and alternative OPAT delivery models remains unknown. Furthermore, the generalizability of these cost findings across Canadian jurisdictions may be limited by differences in funding arrangements, availability of different OPAT delivery models, and infrastructure across provinces and territories. Therefore, available cost estimates should be interpreted with caution.

Guidelines

Two guidelines supported the use of OPAT as a safe and effective option for antimicrobial therapy for appropriately selected patients.^1,21 Common recommendations included delivery of OPAT through a formal multidisciplinary program with clear governance structures, as well as involvement of an ID specialist or consultant in the management of OPAT, patient selection, treatment planning, and ongoing monitoring. Regular follow-up and monitoring of treatment response, adverse events, and complications were also commonly recommended.^1,21 Self-administered OPAT was encouraged for all patients, with each guideline emphasizing the importance of patient selection, education, and monitoring.^1,21 One guideline²¹ endorsed the use of telemedicine to support home-based OPAT services and provided recommendations for patients who have been historically excluded from OPAT — PWID and older adults.^1,21

Considerations for Future Research

To understand the impact of different OPAT delivery models on patients, higher quality evidence is needed. Future studies with larger sample sizes and populations that are historically excluded from OPAT, such as older adults and PWID, should be conducted. This will allow the evidence base to grow and support the development of strong recommendations to guide OPAT care for these populations. Studies also need to stratify results between the different populations so that details about adverse events or treatment success in vulnerable populations can be gained and suitable models of OPAT delivery can be established for different patient groups. There is also limited evidence regarding the use of OPAT in rural or remote settings. Evidence regarding the effectiveness of different delivery models would be useful for health facilities that cover smaller geographical areas. In addition, there is a lack of evidence on how telemedicine can be used in OPAT and its effectiveness in different delivery models on patient outcomes.

There is limited evidence on physician, caregiver, or patient satisfaction with different OPAT delivery models. High satisfaction with different delivery models will facilitate the adoption of less resource-heavy OPAT models. However, there is limited evidence on how OPAT teams feel about the use of telemedicine or how patients and caregivers feel about increased responsibilities associated with self-administered OPAT.

Cost-effectiveness and cost-utility analyses in Canada would be helpful in understanding the value of OPAT compared to inpatient care as well as different OPAT delivery models. This can provide useful data to jurisdictions about the most cost-effective models of OPAT delivery as well as ways to reduce costs associated with OPAT.

Limited evidence described the landscape of OPAT care in Canada. Future research could include a national survey that aims to show the availability of OPAT programs, different delivery models, operational and structural characteristics, along with implementation considerations. This could help identify variations in practice and inform the development or expansion of OPAT services in Canadian jurisdictions. There was also limited comparative research assessing the effectiveness of different OPAT delivery models in Canada. To address current evidence gaps, more studies could be done to assess patient-centred outcomes, patient (and caregiver) satisfaction, and the impact of OPAT on metrics such as ED visits. The development of local, provincial, or national OPAT registries may facilitate future research as well as help identify areas for quality improvement.

Most studies included in this review evaluated OPAT delivered in a formalized program with structured teams and processes; however, this may not be representative of how patients receive OPAT. Many patients across Canada may not have access to dedicated OPAT teams; therefore, it remains unclear if the benefits observed in formalized programs are generalizable to OPAT delivered outside of a formalized program. Future research could compare these models to determine impacts on patient outcomes, health care utilization, cost-effectiveness, and patient and caregiver experiences.

Considerations for Clinical Practice or Considerations for Decision- or Policy-Making

This rapid review suggests that, among appropriately selected adult patients who require IV antimicrobial therapy outside inpatient settings, OPAT may be a safe and effective alternative to inpatient care. However, the evidence did not consistently demonstrate differences in clinical outcomes and patient safety between OPAT and inpatient care, or between different OPAT delivery models. Likewise, evidence suggests that self-administered OPAT may be an option to health care–administered OPAT for appropriately selected patients. The location and setting of OPAT administration appear to be less important than the selection of patients. Guidelines consistently recommend the importance of clear criteria for patient selection, which is supervised or developed by an ID specialist (i.e., physician). Decision-makers may therefore wish to consider the processes and resources required to support patient assessment, selection, and monitoring for OPAT implementation or expansion. However, it is also crucial to note that the identified evidence is generally of low quality and was conducted outside of Canada, which may limit its applicability to Canadian contexts.

Evidence generated in Canada suggests that OPAT may be associated with lower direct health care costs than IPAT.^18,25 Limited evidence also indicates that costs may vary across OPAT delivery models, with some community-based approaches (i.e., community IV antibiotics with return to ED if necessary) potentially associated with lower costs than OPAT clinic-based care.²⁵ However, no cost-effectiveness or cost-utility analyses performed in Canada were identified. As a result, the relative value for money of OPAT compared with IPAT, and of alternative OPAT delivery models compared with one another in Canada, remains unknown. Decision-makers may wish to consider other limitations of the available evidence — which is limited to nonrandomized studies reporting costs only and does not account for the impact of OPAT on health outcomes. They may also wish to consider costs that may fall outside the health care system perspective, including those borne by patients, caregivers, and community health care providers. In addition, implementation of OPAT programs may require investments in infrastructure, care coordination, and hospital pharmacy services, which could affect the overall cost implications of adopting or expanding OPAT programs.

The guidelines identified in this review underscored the importance of ID specialists in OPAT teams playing a role in patient selection, treatment planning, and ongoing monitoring. In addition, a formal multidisciplinary team was recommended with clear governance structures. One guideline also supported the use of telemedicine to support home-based OPAT. Therefore, decision-makers may wish to consider the availability of ID specialists, specialist or trained OPAT nurses, pharmacists, and community health care resources (home care nurses) within their jurisdiction. Furthermore, guidelines also consistently recommended regular follow-ups and ongoing monitoring regardless of delivery models, which has implications for staff capacity and infrastructure.

Both guidelines encouraged the prescription of self-administered OPAT for appropriately selected patients. These guidelines also specified that patients and caregivers should receive adequate training and support by qualified OPAT team members. However, there is a paucity of evidence on the satisfaction of patients and caregivers regarding this model of care, as well as the impacts of treatment burden or caregiver well-being of expanded adoption of home-based OPAT. Decision-makers may wish to consider these factors when deciding which OPAT programs to prescribe, given that home-based treatment may transfer some responsibilities to patients and caregivers. Likewise, there is limited to no evidence on health care providers’ acceptance, experience, and satisfaction with the use of telemedicine in OPAT.

BSAC recommends that oral antimicrobial therapy be used in preference to IV therapy when the 2 therapies have equivalent efficacy and there is an absence of concerns such as toxicity, lack of oral route, allergies, or drug-to-drug interactions. Recent evidence suggests that oral regimens can be used to manage and treat infections that were treated with prolonged IV antibiotics.³⁴ As a result, health care systems have developed newer models of OPAT, such as complex outpatient antimicrobial therapy, that integrate oral and IV antimicrobial therapy. Decision-makers may wish to consider that OPAT care is evolving, and future service planning may need to consider emerging models, like complex outpatient antimicrobial therapy models with patients also receiving oral antimicrobial therapy.

This review did not assess environmental outcomes. However, during screening, some literature was identified that suggests that OPAT, namely home-based OPAT, may be associated with reduced carbon emissions, waste generation, transportation requirements (of patients at home), and water use. Decision-makers may wish to consider these factors, along with clinical and economic outcomes, if interested in sustainable health care delivery.³⁵

Evidence describing models of OPAT care in Canada was limited, and results were retrieved from programs in metropolitan cities. There are differences in health care delivery, availability of specialists, and access to community-based services across jurisdictions. Decision-makers may therefore wish to consider local infrastructure, patient populations, and health care system capacity when interpreting and applying the findings of this review.

Acknowledgements

The authors would like to thank the content expert who externally reviewed this document and who has granted permission to be cited.

Philip Lam, MD, MSc, FRCPC

Medical Director of Antimicrobial Stewardship, Sunnybrook Health Sciences Centre

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Appendix 1: Detailed Methods and Selection of Included Studies

Please note that this appendix has not been copy-edited.

What Is a Rapid Review?

Rapid reviews are based on accelerated and abbreviated SR methods, balancing timeliness with rigour, to allow for timely decision-making. Due to these abbreviated methods, rapid reviews have some limitations. For example, in the initial scoping, an evidence-based guideline by the Infectious Diseases Society of America was identified that was published in 2019. To capture this guideline document and in consultation with the external requestor, we set our search time frame from January 2018 onward. Unlike SRs, a single reviewer was required to include, extract data, and appraise studies. In addition, we included studies published from 2018, excluding older studies. We attempted to mitigate this by searching for and including relevant SRs published in the past 8 years that included older studies. Focusing on more recently published articles may also be more reflective of current practices. Our rapid review intends to summarize the available evidence, rather than provide recommendations. These findings should not be interpreted as prescriptive guidance.

Literature Search Methods

An information specialist conducted a literature search on key resources including MEDLINE, the Cochrane Database of Systematic Reviews, the International HTA Database, the websites of health technology assessment agencies in Canada and major international HTA agencies, as well as a focused internet search. The search approach was customized to retrieve a limited set of results, balancing comprehensiveness with relevance. The search strategy comprised both controlled vocabulary, such as the US National Library of Medicine’s MeSH (Medical Subject Headings), and keywords. Search concepts were developed based on the elements of the research questions and selection criteria. The main search concepts were outpatient parenteral antibiotic therapy. The search was completed on April 2, 2026, and limited to English-language documents published since January 1, 2018. The search strategy is available on request.

Selection Criteria and Methods

One reviewer screened citations and selected studies. In the first level of screening, titles and abstracts were reviewed and potentially relevant articles were retrieved and assessed for inclusion. The final selection of full-text articles was based on the inclusion criteria presented in Table 1.

Exclusion Criteria

Articles were excluded if they:

• did not meet the selection criteria outlined in Table 1

• were duplicate publications or were published before January 2018

• were SRs in which all relevant studies were captured in other more recent or more comprehensive SRs

• were primary studies captured in 1 or more included SRs

• were guidelines with unclear methodology or published in languages other than English

• were economic evaluations conducted outside of Canada

Critical Appraisal of Individual Studies

The included publications were critically appraised by 1 reviewer using the following tools as a guide: A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR 2)⁶ for SRs, the Revised Risk of Bias Assessment Tool for Nonrandomized Studies of Interventions (RoBANS 2) ⁸ for nonrandomized studies, and the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument⁷ for guidelines. Summary scores were not calculated for the included studies; rather, the strengths and limitations of each included publication were described narratively.

Data Extraction

One reviewer extracted data directly into standardized tables created in Microsoft Word, which were modified as necessary. The extracted information included study characteristics, methodology (e.g., study design), population, intervention, comparator, and results regarding the outcomes of interest.

One reviewer extracted information from the included studies using the PROGRESS-Plus³⁶ tool to describe different population groups. Each included study was checked to determine if PROGRESS-Plus⁵⁵ criteria were reported by study authors to describe the participants; detailed characteristics, if available, were then extracted and reported in tables in Appendix 2. The main PROGRESS-Plus³⁶ criteria include place of residence; race, ethnicity, culture, and/or language; occupation; gender and/or sex; religion; education; socioeconomic status; and social capital. As part of report writing, we discuss these characteristics across the evidence, where available, when presenting results within the text.

When reporting on sex, gender, race, or ethnicity in this rapid review, we planned to retain the language used by the original study authors, and, whenever possible, we referred to these groups based on guidance from Canada’s Drug Agency Style: A Guide for Authors and Editors³⁷ at the time this rapid review was conducted, with an understanding that language is constantly evolving.

External Review

The final report was externally reviewed by a content expert with experience in antimicrobial stewardship.

Appendix 2: Selection of Included Studies

Please note that this appendix has not been copy-edited.

Figure 1: Selection of Included Studies — PRISMA²⁷ Flow Chart of Selected Reports

PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Appendix 3: Characteristics of Included Publications

Please note that this appendix has not been copy-edited.

Included Studies for Question 1: Models of OPAT Care in Canada

We identified 3 nonrandomized studies addressing this question.^22-24 Two studies were retrospective cohorts^22,24 and 1 was an interrupted time series.²³ All 3 studies were conducted in Canada, 2 in Ontario (Ottawa²³ and Toronto ²²) and 1 in Vancouver, British Columbia²⁴. All studies were conducted in academic health sciences,²² care,²⁴ or medical centres.²³

All studies reported the infusion locations and the type of health care professionals who work in the program or clinic. Two studies^22,23 reported details on patient referrals as well as work hours of ID physicians²⁴ and nurses.²³

Included Studies for Question 2: Clinical Effectiveness of OPAT Compared to IPAT and Alternate OPAT Delivery Models

We identified 12 publications that addressed this question, 1 HTA,⁹ 3 SRs,^10-12 and 8 primary studies.^13-20 The 3 SRs included meta-analyses.^10-12 The HTA was conducted by the Scottish Health Technologies Group⁹ and the SRs were conducted by groups in Australia,¹⁰ US,¹² and the UK.¹¹ The HTA included only SRs,⁹ 1 SR only included RCTs¹⁰ and 2 SRs included all study designs, namely nonrandomized studies (observational).^11,12 1 SR also included conference abstracts and case series due to the limited nature of studies regarding the use of telemedicine in OPAT.¹¹ The overlap in primary studies between SRs is reported in Appendix 7. The 3 SRs searched for published literature from inception to July 2022¹¹ and April 2023.¹² One SR¹⁰ did not report search dates but reported they had no restrictions on publication year and the HTA⁹ did not report search dates. 1 SR¹¹ restricted their studies to only those published in English. Eight primary studies were identified which were all retrospective cohort studies.^13-20 Studies were conducted in Canada,¹⁸ US,^13,14,17 UK,^16,19 Australia,¹⁵ and Spain.²⁰

All studies included adult participants who required IV antibiotic therapy. Two SRs^10,11 also included studies with pediatric populations but only data regarding adult participants was included in this report. Studies reported population characteristics in varying detail. One SR provided the age range of the study population and the sex distribution.¹⁰ The number of participants in the SRs ranged from 2 to 636 and the number of participants in the primary studies ranged from 101 to 1,861 with ages ranging from 18 to 92 years. Most primary studies included patients older than 65 years. Some studies had participants with a median age of older than 65 years.^14,16,20 Two studies reported that around 44%¹⁸ and 51%¹⁵ of the study population was older than 65 years. One study only reported the total OPAT episodes in the study period, 7,612.¹³. For all studies, authors provided the number or percentage of female and/or male participants; other genders were not reported. For the studies that reported on the sex distribution, study populations included more males ranging from 53% to 70.6% of the total study population.^{10,13,15,16,18,20} Two studies included people who inject drugs (PWID), but results were not separated between PWID and those that do not.^10,16 Likewise, 1 study included patients with opioid abuse at index admission.¹⁸ One study had a self-administered OPAT program for patients who were uninsured or underinsured.¹³ Another study reported the neighbourhood household income and urban residence of participants in both the intervention and comparator.¹⁸ Likewise, 1 study was conducted in small community hospitals each with less than 200 beds that received telemedicine consultations.¹⁴ Only 1 study reported the body mass index, ethnicity and race of participants, as well as the percentage of participants that spoke Spanish or other languages (not specified).¹³ None of the studies provided information on education, occupation, religion, or social capital.

Some studies reported on patients with only 1 infection and some studies included patients with multiple infection types. Infections of patients included were:

• Bone and Joint infections (4 studies)^12,14,15,18

• Osteomyelitis (4 studies)^12,15,18,19

• Urinary tract infection (4 studies)^10,12,14,19

• Infective endocarditis (3 studies)^12,16,20

• Intra-abdominal infections (3 studies)^12,14,19

• Respiratory infections (3 studies)^10,14,19

• Skin and soft tissue infections (3 studies)^12,14,19

• Cellulitis (2 studies)^10,17

• Staphylococcus aureus bacteremia (2 studies)^10,18

The interventions in the included studies were OPAT. The models of OPAT found in the studies were:

• Home-based (health care administered via home health service and self-administered after being trained by health care professional)^{12,13,15,18,20}

• Facility-based (clinic led, infusion centre, or ED)^9,12,17,18

• Telemedicine managed^11,14

• Community nurse–led or community IV antibiotic service^9,16

Health care–administered OPAT refers to any IV antimicrobials delivered by trained health care personnel at the patient’s home via home health services, infusion centres or at skilled nursing facilities.^13,15,20 Self-administered OPAT refers to patients or caregivers administering IV antimicrobials at the patient’s home. Patients are trained on how to administer IV antimicrobials before being discharged.^13,15 With self-administered OPAT, patients are still required to attend the clinic for monitoring and laboratory tests to ensure they are not experiencing any adverse events.¹³ Facility-based OPAT refers to any OPAT that occurs at clinics, hospital wards, or in the ED.^12,17 Tele-OPAT refers to the use of telemedicine in the provision of OPAT services. This can either be in the form of video or telephone consultations during the delivery of parenteral antibiotics in the patient’s home or in clinics.¹¹ This can also be telehealth facilitated calls by ID clinicians or consultants for consultation or follow-up after hospital discharge.¹⁴ Community facilitated OPAT services refer to a dedicated team of clinicians (nurses, doctors, pharmacists) that administer antibiotics in the patient’s home.

Comparisons were made between:

• OPAT versus inpatient or hospital-based care including IPAT (5 studies)^{9,10,17,18,20}

• Health care–administered versus self-administered in the patient’s home (2 studies)^13,15

• Tele-OPAT versus conventional OPAT without the use of telemedicine (2 studies)^11,14

• Community-led OPAT versus other models of OPAT i.e., ward based or self-administered (2 studies)^16,19

• Self-administered OPAT versus non-self-administered OPAT at the clinic (1 study)¹⁹

• Facility versus home-based OPAT (1 study)¹²

IPAT or hospital-based parenteral antimicrobial therapy refers to IV antimicrobials administered to patients in inpatient settings, while still being admitted in the hospital. Conventional OPAT refers to OPAT administered without the use of telemedicine at any stage.^11,14

Clinical effectiveness and safety outcomes assessed in the studies were:

• Readmission (30 day or 90-day readmission, all-cause unplanned readmission, readmission due to complication, risk of readmission) (6 studies)^{9,11,12,14,17,20}

• Safety (adverse drug reactions, device-related adverse reactions, complications, bloodstream infections, risk of developing complications, acute kidney injury, venous thromboembolism, C. difficile diarrhea, neutropenia) (8 studies)^{9,10,13-16,18,19}

• Mortality (5 studies)^{9,10,14,18,20}

• Treatment failure (5 studies)^{10,12,14,15,19}

• Success and cure (3 studies)^9,15,19

• Duration of treatment (2 studies)^9,10

• Days in hospital^18,20

• Laboratory results monitoring and ID clinic follow-up (1 study)¹²

OPAT failure or treatment failure was defined in various ways across studies including a worsening of infection or an adverse event that results in a death or readmission during the OPAT period.^14,19 An OPAT success or clinical cure was defined variably across studies as improvement in infection or completed therapy with no change in antimicrobial or adverse events.¹⁹

Additional study details can be found in Appendix 3. Additional references of potential interest that did not meet the inclusion criteria are provided in Appendix 8.

Included Studies for Question 3: Cost-Effectiveness of OPAT Compared to IPAT and Alternate OPAT Delivery Models

No economic evaluations conducted in Canada were identified to address this question.

However, 2 nonrandomized retrospective cohort studies^18,25 performed in health care settings in Canada were identified that provide context on the costs of OPAT compared with IPAT in British Columbia¹⁸ and Ottawa.²⁵ While these studies offer insights into resource use and costs within the Canadian context, they do not assess the cost-effectiveness or value of the intervention. Therefore, they were not included in our analysis. Additional details are provided in Appendix 6.

Included Studies for Question 4: Recommendations Regarding the Delivery of OPAT

Two evidence-based guidelines^1,21 were identified to address this question. The guidelines were produced by the:

• British Society for Antimicrobial Chemotherapy (BSAC)²¹ in the UK in 2026

• Infectious Diseases Society of America (IDSA)¹ in US in 2019

Two guidelines conducted a systematic literature review to create the evidence base for recommendation.^1,21 Databases were searched for published studies from 2017 to 2025 for BSAC²¹ and 1946 to publication year for IDSA.¹ For the BSAC recommendations, recommendations were developed based on systematic review and expert consensus from a panel of OPAT specialist physicians, nurses, and pharmacists.²¹ Evidence was appraised by the core working group who then created a draft list of recommendations that were sent for consultation to external partners.²¹ IDSA used the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE)^28-31 approach to develop recommendations and received feedback from external peer reviewers.¹ The quality of evidence and strength of recommendations were reported by 1 guideline group, IDSA.¹ Evidence informing a question and recommendation was rated “high quality” if it included RCTs and was rated “low quality” if it only included nonrandomized clinical trials or observational studies. The strength of recommendations reflected the benefits and harms, as well as level of evidence available for each recommendation.¹

The intended users of the guidelines were OPAT teams including clinicians who prescribe or oversee the provision of any IV antimicrobials outside of the inpatient setting. One guideline group specified the intended users.^1,32 Each guideline was created for people who require IV antimicrobials outside of the inpatient setting. Recommendations were provided regarding the governance and structure of OPAT teams;²¹ ID physician or specialist involvement;^1,21 follow-up and monitoring requirements for each patient.^1,21 Furthermore, recommendations for OPAT for specific populations that were previously excluded from OPAT (i.e., older adults, PWID) were provided by both groups.¹ Both groups also provided recommendations regarding self-administered OPAT and BSAC provided a recommendation regarding telemedicine use.^1,21

Additional references of potential interest that did not meet the inclusion criteria are provided in Appendix 8.

Table 3: Characteristics of Systematic Reviews

AE = adverse event; CKD = chronic kidney disease; DVT = deep vein thrombosis ID = infectious diseases; IE = infective endocarditis IPAT = inpatient parenteral antimicrobial therapy; MA = meta-analysis; NA = not applicable; NR = not reported; NRS = nonrandomized studies; OPAT = outpatient parenteral antimicrobial therapy; RCT = randomized controlled trial; SR = systematic review; SSTI = skin and soft tissue infection; UTI = urinary tract infection; vs. = versus.

^aThis N included participants for all RCTs included in the SR with 2 RCTs with pediatric patients.

^bInfection type were reported as acute illnesses and infectious diseases and then broken down*

Table 4: Characteristics of Included Nonrandomized Studies

AE = adverse event; AKI = acute kidney injury; BJI = bone and joint infections; BSI = bloodstream infections; CIVAS = community IV antibiotic service; CNS = central nervous system; ED = emergency department; H OPAT = health care–administered OPAT; ID = infectious diseases; IDt = telehealth-managed OPAT; IE = infective endocarditis; NA = not applicable; NR = not reported; OPAT = outpatient parenteral antimicrobial therapy; S OPAT = self-administered OPAT; SOC = standard of care; SSTI = skin and soft tissue infection; UTI = urinary tract infection; VTE = venous thromboembolism.

^aBSI is defined as microbiologically confirmed BSIs diagnosed within 90 days of hospital discharge for H OPAT or BSIs diagnosed before the end of the treatment period for S -OPAT patients for central line, peripheral catheters or midline removals tall beyond central line-associated BSI surveillance

Table 5: Characteristics of Included Guidelines

BSAC = British Society for Antimicrobial Chemotherapy; GRADE = Grading of Recommendations, Assessment, Development, and Evaluation; IDSA = Infectious Diseases Society of America; NR = not reported; OPAT = outpatient parenteral antimicrobial therapy.

Appendix 4: Critical Appraisal of Included Publications

Please note that this appendix has not been copy-edited.

Included Studies for Question 1: Models of OPAT Care in Canada

The nonrandomized studies identified were used in this report to retrieve details regarding the models of OPAT care but not on the impact of OPAT on patient outcomes. Therefore, no critical appraisal of studies was conducted.

Included Studies for Question 2: Clinical Effectiveness of OPAT Compared to IPAT and Alternative OPAT Delivery Models

AMSTAR 2⁶ was used to appraise the HTA and SRs and RoBANS 2⁸ was used for nonrandomized studies.

HTA and Systematic Reviews

Two SRs,^10,11 included all components of PICO in their research questions and inclusion criteria. This increases the transparency of methodology and reproducibility. One SR¹² did not include details about the population and the HTA⁹ only included details about the intervention and outcomes in the research question and inclusion criteria. Three SRs^10-12 had their protocols registered in PROSPERO and the HTA⁹ reported the review questions that guided the report. This minimizes the risk of reporting bias even though none of the publications had an explicit statement that review methods were established before the conduct of the review. Three publications^9,10,12 did not explain the selection and inclusion of specific study designs in their reviews. One SR on telemedicine in OPAT reported their reason for the inclusion of lower quality sources such as conference abstracts and case series — a paucity of research on the use of telemedicine in OPAT.¹¹

All publications searched at least 5 databases, thus minimizing the risk of missing relevant studies. Two SRs^10,11also searched the reference lists of included studies of included studies and review articles. One SR also searched trial and study registries.¹¹ The Scottish Health Technologies Group also broadened their search to websites for relevant publications such as guidelines, patient experiences, policy documents, and so forth.⁹ Two publications restricted their search to studies published in English, which could have led to missing relevant data in other languages and introduced selection bias.^9,11 One SR provided a justification for the restriction — lack of interpreters or translators on the team.¹¹ At least 2 authors performed study selection independently and in duplicate in all SRs, thus decreasing the risk of inaccuracies and reduction in human error during screening. One SR also reported that data extraction was performed in duplicate, which increases the likelihood that extracted data was more accurate and complete.¹¹ Another SR reported that 1 author performed data extraction which was reviewed and verified by another.¹⁰ It was unclear if study selection and data extraction was conducted independently and in duplicate in 1 SR.¹² No details about study selection and data extraction were provided in the HTA.⁹ Two SRs^10,11 provided a list of excluded studies and the reasons for exclusions while the other 2 publications did not, which increases transparency and allowed us to ensure that the relevant studies were included in the review.

All publications provided adequate detail about included studies. Review authors provided details about the included studies population characteristic, study design, outcomes, and interventions. As a result, it was easier to assess the applicability and relevance of included studies. Sources of funding of included studies were not provided in all publications. Three SRs also used a satisfactory technique to assess the risk of bias of included studies. Mixed Methods Appraisal Tool,¹¹ Cochrane Risk of Bias,¹⁰ and Downs and Black¹² were used. The HTA did not provide details about the technique used to assess the quality of included SRs, but they did report on the risk of bias tools used by the review authors of the included SRs. ⁹

Three systematic reviews conducted a meta-analysis.^10-12 Appropriate methods were used for the statistical combination of results, including random-effects model with inverse variance weighting in 1 SR¹². Heterogeneity of studies was assessed with the I-squared statistic in all SRs. One SR¹² also used the Cochran’s Q statistic to assess heterogeneity, and 1 SR¹⁰ also conducted sensitivity and subgroup analyses. Publication bias was investigated in 2 SRs with a funnel plot^10,12 and an Egger’s regression test.¹⁰ The potential risk of bias of individual studies and heterogeneity between studies was discussed and accounted for when interpreting results in all publications.

All publications reported potential sources of conflict of interest.

Nonrandomized Studies

All nonrandomized studies were assessed as having a high risk of bias. Selection bias was the highest risk in all studies due to statistically significant differences in baseline characteristics, as well as differences in patient selection between the treatment groups.^13,14 Therefore, differences in treatment groups may have influenced the observed outcomes, making it difficult to determine the impact of OPAT on patient outcomes. Four studies^13,15,16,18 tried to account for main confounders to minimize selection bias, however, not all confounders were adjusted for such as race or severity of infection.^13,14 One study conducted in Canada also tried to minimize confounding with a matched cohort study design, whereby participants were matched based on infection types (exact matches) and implied duration of IV antimicrobials.¹⁸ Other studies also tried to minimize selection bias by including participants with 1 infection type, for instance only patients with acute uncomplicated cellulitis¹⁷ or infective endocarditis.¹⁶ In addition, 1 study conducted consecutive recruitment of patients that met the inclusion criteria to minimize selection bias.¹⁶ However, conclusions need to be interpreted cautiously as there may still be residual confounding.

Performance bias was rated low in each study as interventions and outcome measures were confirmed from trustworthy sources such as medical records or administrative databases. Therefore, it is likely that outcome and treatment data were accurately captured. Detection bias was also rated low or unclear in most studies. Where blinding of outcome assessors was not conducted, objective outcomes were assessed, such as hospital readmission or death.^13,16-20 In some instances, there was a high risk of detection bias due to nonobjective outcome measurement (outcomes that relied on the judgment of clinician and criteria was not available via patient medical records) or no blinding done on investigators collecting data (i.e., reviewers were not blinded to study objectives).^14,19 In these instances, the lack of blinding may have affected outcome measurement.

Attrition bias was reported as unclear in all studies, as it was not reported whether or not missing data affected outcomes. Reporting bias was also low in all studies due to the fact that expected and previously determined relevant outcomes were fully reported. This reduces the likelihood that there was selective reporting.

Included Studies for Question 3: Cost-Effectiveness of OPAT Compared to IPAT and Alternative OPAT Delivery Models

No economic evaluations conducted in Canada were identified, therefore no summary can be provided.

Included Studies for Question 4: Recommendations Regarding the Delivery of OPAT

Two guidelines were identified about OPAT. The AGREE II tool was used to critically appraise them.⁷

The overall objectives and scope covered by guidelines were specifically described in both guidelines.^1,21 In addition, the population to whom the guideline is meant to apply to was specifically described — people who require IV antibiotics in outpatient settings.^1,21 Both guidelines also provided recommendations for individuals previously excluded from OPAT including older adults. One guideline clearly defined the target users of the guideline — clinicians who prescribe and oversee the provision of OPAT.^1,21 All guidelines were developed by individuals from all relevant professional groups, including ID physicians, clinical microbiologists, OPAT nurses, and program managers. Thus, recommendations are more likely to balanced, applicable, and acceptable to all professionals who the guideline were developed for. It was unclear if the views and preferences of the target population were sought for each guideline.

The guideline groups used systematic methods to search for evidence, therefore increasing the likelihood that recommendations were informed by comprehensive assessments of literature.^1,21 However, the quality of evidence was assessed in only 1 guideline, the IDSA.¹ BSAC noted that they did not include levels of evidence in the guideline due to the nature of most studies (namely observational studies, case series, and noninterventional).²¹ Both guidelines clearly described how they developed and created recommendations and considered the health benefits, side effects and risks when formulating recommendations. In addition, there was an explicit link between recommendations and supporting evidence provided in both guidelines. When there was limited evidence for a particular recommendation, BSAC noted it.

Both guidelines were reviewed externally before their publication, however details about the update procedure were provided by 1 group, IDSA.^1,21 BSAC did not provide procedures for updating their recommendations, but this edition was an update of a previous publication.²⁶ Recommendations were specific and unambiguous in each guideline with key recommendations easily identifiable.^1,21

All guidelines provided advice and tools on how recommendations can be put into practice. In addition, each group provided resource implications of applying the recommendations such as staffing requirement, need for specialized staff and infrastructure needed. Each guideline also provided monitoring criteria.

The BSAC guideline group reported that the views of the funding body did not influence the content of the guideline; this was not clear from other guidelines.²⁶ Both groups also recorded and addressed the competing interests of the guideline development group.^1,21

Table 6: Strengths and Limitations of Systematic Reviews Using AMSTAR 2⁶

AMSTAR 2 = A MeaSurement Tool to Assess systematic Reviews 2; OPAT = outpatient parenteral antimicrobial therapy; RCT = randomized controlled trial; RoB = risk of bias; SHTG = Scottish Health Technologies Group.

Table 7: Summary of the Strengths and Limitations of Nonrandomized Intervention Studies Using the RoBANS 2⁸ checklist

AE = adverse event; BSI = bloodstream infection; OPAT = outpatient parenteral antimicrobial therapy; RoBANS 2 = revised Risk of Bias Assessment Tool for Nonrandomized Studies.

Table 8: Strengths and Limitations of Nonrandomized Intervention Studies Using the RoBANS 2 Checklist⁸

AE = adverse events; BSAC = British Society for Antimicrobial Chemotherapy; BSI = bloodstream infect; CIVAS = community IV antibiotic service; CLABSI = central line-associated bloodstream infection; H OPAT = health care–administered OPAT; ID = infectious diseases; IDSA = Infectious Diseases Society of America; IDt = telehealth OPAT managed by ID consultant; IE = infective endocarditis; IPAT = inpatient parenteral antimicrobial therapy; IPTW = inverse probability of treatment weighting; OPAT = outpatient parenteral antimicrobial therapy; RoBANS 2 = revised Risk of Bias Assessment Tool for Nonrandomized Studies; SOC = standard of care.

Note: G33665 fee is paid to ID physicians in collaboration with OPAT program staff in British Columbia to incentivize supervision of OPAT.

Table 9: Evidence-Based Guidelines for OPAT — Strengths and Limitations of Guidelines Using AGREE II⁷

AGREE II = Appraisal of Guidelines for Research and Evaluation II; BSAC = British Society for Antimicrobial Chemotherapy; ID = infectious diseases; IDSA = Infectious Diseases Society of America; NA = not applicable; NR = not reported; OPAT = outpatient parenteral antimicrobial therapy.

Note: Categories Yes, Partial Yes, and No were determined using the Likert Scale on the AGREE II tool. Yes (Scores 5 to 7); Partial Yes (Scores 3 to 4); No (Scores 1 to 2).

^aLanguage used in original source.

Appendix 5: Main Study Findings

Please note that this appendix has not been copy-edited.

Table 10: Summary of Findings by Outcome — Readmission

CI = confidence interval; IDt = telehealth by infectious disease physician; IPAT – inpatient parenteral antimicrobial therapy; IPTW = inverse probability of treatment weighting; MA = meta-analysis; NA = not applicable; NR = not reported; OPAT = outpatient parenteral antimicrobial therapy; OR = odds ratio RR = risk ratio; SOC = standard of care; SR = systematic review.

Note: P < 0.05 = significant difference

Table 11: Summary of Findings by Outcome — Safety

ADR = adverse drug reaction; AE = adverse event; AKI = acute kidney injury; BSI = bloodstream infection; CIVAS = community IV antibiotic service; MA = meta-analysis; H OPAT = health care–administered OPAT; ID = infectious diseases; IDt = telehealth-managed OPAT by ID physician; IPAT = inpatient parenteral antimicrobial therapy; NA = not applicable; NR = not reported; OPAT = outpatient parenteral antimicrobial therapy; OR = odds ratio; RCT = randomized controlled trial; RR = risk ratio; S OPAT = self-administered OPAT; SR = systematic review; VTE = venous thromboembolism.

Note: P < 0.05 is significant difference between 2 groups

^aAdjusted analyses presented account for infection type, IDIVA, age, and Charlson (comorbidity score).

Table 12: Summary of Findings by Outcome — Mortality

CI = confidence interval; IDt = telehealth by infectious disease physician; IPAT = inpatient parenteral antimicrobial therapy; IPTW = inverse probability of treatment weighting; MA = meta-analysis; NA = not applicable; NR = not reported; OPAT = outpatient parenteral antimicrobial therapy; OR = odds ratio RR = risk ratio; SHTG = Scottish Health Technologies Group; SOC = standard of care; SR = systematic review.

Note: P < 0.05 is significant difference between 2 groups

^aAdjusted analyses presented account for infection type, IDIVA, age, and Charlson (comorbidity score).

Table 13: Summary of Findings by Outcome — Treatment Failure

CI = confidence interval; IDt = telehealth by infectious disease physician; H OPAT = health care–administered OPAT; IPAT = inpatient parenteral antimicrobial therapy; IPTW = inverse probability of treatment weighting; MA = meta-analysis; NA = not applicable; NR = not reported; OPAT = outpatient parenteral antimicrobial therapy; OR = odds ratio; RR = risk ratio; S OPAT = self-administered OPAT; SOC = standard of care; SR = systematic review.

Note: P < 0.05 is significant difference between 2 groups

Table 14: Summary of Findings by Outcome — Success and Cure

CI = confidence interval; H OPAT = health care–administered OPAT; IPAT = inpatient parenteral antimicrobial therapy; NA = not applicable; NR = not reported; OPAT = outpatient parenteral antimicrobial therapy; OR = odds ratio; RR = risk ratio; S OPAT = self-administered OPAT; SHTG = Scottish Health Technologies Group; SOC = standard of care.

Note: P < 0.05 is significant difference between 2 groups

Table 15: Summary of Findings by Outcome — Other Outcomes

CI = confidence interval; ID = infectious diseases; H OPAT = health care–administered OPAT; IPAT = inpatient parenteral antimicrobial therapy; IPTW = inverse probability of treatment weighting; LOS = length of stay; MA = meta-analysis; NA = not applicable; NR = not reported; OPAT = outpatient parenteral antimicrobial therapy; OR = odds ratio; RCT = randomized controlled trial; RR = risk ratio; S OPAT = self-administered OPAT; SHTG = Scottish Health Technologies Group; SOC = standard of care; SR = systematic review; vs. = versus.

Note: P < 0.05 is significant difference between 2 groups

Table 16: Summary of Recommendations in the Included Guidelines

ADR = adverse drug reaction; AE = adverse event; AWMF = Association of the Scientific Medical Societies; BSAC = British Society for Antimicrobial Chemotherapy; H OPAT = health care–administered OPAT; ID = infectious diseases; IDSA = Infectious Diseases Society of America; MC = midline catheters; NA = not applicable; NR = not reported; NRS = nonrandomized studies OPAT = outpatient parenteral antibiotic therapy; PICC = peripherally inserted central catheter; PWID = people who inject drugs; S OPAT = self-administered OPAT; SHTG = Scottish Health Technologies Group; SR = systematic reviews; vs. = versus.

Note: The strength of the consensus was classified as “strong consensus” when more than 95% of participants in the guideline development group agreed, “consensus” when 75% to 95% of participants agreed, “majority agreement” if 50% to 75% of participants agreed, and “no consensus” if less than 50% of participants agreed.

Appendix 6: Costing Studies Summary of Study Characteristics

Please note that this appendix has not been copy-edited.

Two nonrandomized retrospective cohort studies conducted in Canada were excluded from the main report but described here that provide some economic considerations as they provided information regarding costs.^18,25 One study included adult patients diagnosed with cellulitis and discharged from the ED and the other included adult patients with an unplanned hospital admission that had a bacterial infection that required extended IV antimicrobials. These studies included primary cost comparisons between OPAT and IPAT^18,25 from health care systems in Canada (British Columbia¹⁸ and Ottawa²⁵), and reported their results in 2015²⁵ and 2018 Canadian dollars.¹⁸The study by Yadav et al. (2022) compared health care costs between patients receiving their IV antibiotics in the OPAT clinic,²³ patients returning to the ED to receive their antibiotics, or patients admitted into the hospital for IV antibiotic treatment.²⁵

The study by Staples et al. (2022) (British Columbia) estimated health care costs from the health care funder or insurer perspective. Hospitalization costs were estimated using costs of a standard hospital stay and the resource intensity weight. This is a value that describes the expected resources used by a patient.³⁹ Costs associated with OPAT were modelled based on actual costs in British Columbia such as regional drug formulary costs or unit costs set by the BC Ministry of Health. The study by Yadav et al. (2022) conducted a cost analysis from a Canadian public payer perspective. Total costs were both direct and indirect. Direct were costs incurred by the hospital with a fee code linked to a patient chart; individual patients were not charged for the care they received, rather the costs were assumed by the health system. Indirect costs were overhead fees associated with services provided by the hospital. Costs were extracted from hospitals’ health administrative databases and electronic medical records.

The outcomes assessed were:

• Cost savings associated with OPAT¹⁸

• Costs associated with ED visits ¹⁸

• Estimated mean total direct health system costs within 90 days of index admission¹⁸

• Costs of OPAT¹⁸

• Mean total health system costs for each treatment strategy (including costs associated with index ED visit, ID physician consultation, OPAT clinic, return ED visits, inpatient care, and community IV antibiotics)²⁵

• Incremental costs per patient for the OPAT treatment strategy compared to hospital admission and return to ED strategies²⁵

Summary of Critical Appraisal

Both studies were assessed as having a high risk of bias. There was a high risk of selection bias due to statistically significant differences in baseline characteristics between treatment groups, thus showing that differences in patient characteristics may have influenced outcomes. Both studies tried to minimize confounding by controlling for main confounders such as age and comorbidities. The study by Staples et al. (2022) also used a matched cohort study design whereby participants were matched based on infection types (exact matches) and implied duration of IV antimicrobials. However, conclusions needs to be interpreted cautiously as there may still be residual confounding. Performance bias was rated low-risk due to the intervention and outcomes being confirmed from trustworthy sources such as medical records and administrative databases. Therefore, it is likely that outcome and treatment data were accurately captured. Detection buas was low as objective outcomes were assessed. In the study by Yadav et al. (2022) patient level costs were assessed and used in the analysis. The study by Staples et al. (2022) modelled studies based on regional costs. It is unclear whether missing data affected outcomes for both studies. Reporting bias was also rated as low-risk as expected or prespecified outcomes were fully reporting, reducing the likelihood of selective reporting.

Summary of Findings

The study conducted in British Columbia¹⁸ (reported in 2018 CA$) found that the estimated mean total direct health system costs within 90 days of initial hospitalization were statistically significantly lower for patients that received OPAT compared to IPAT ($ 30,166 for OPAT versus $50,039 for IPAT). The mean cost difference between the 2 strategies was $17 579 (95% CI, $14,131 to $21,027, cost ratio = 0.60). In addition, OPAT was also associated with statistically significantly lower costs for ED visits and direct costs of OPAT (via IV antimicrobials, nursing, and laboratory) compared to IPAT.

Another study conducted in Ottawa²⁵ (reported in 2015 CA$) found that the mean total care costs per patient were highest for patients admitted to the hospital for IV antibiotic treatment ($10,145; 95% CI $8,668 to $11,622), followed by those managed through an OPAT clinic ($2,170; 95% CI $1,905 to $2,436), and lowest for those receiving community IV antibiotics with return to ED if necessary ($1,493; 95% CI $1,264 to $1,722). The difference in total cost of care (per patient) when these patients were managed through the OPAT clinic was approximately $651 (95% CI $367 to $935) higher than when they were managed through returns to the ED; and approximately $7,394 lower (95% CI $6,154 to $8,633) than when they are admitted into the hospital for IV antibiotic administration – both differences between groups were statistically significant.

Additional details can be found in Table 17.

Table 17: Summary of Findings by Outcome — Cost

CI = confidence interval; ED = emergency department; ID = infectious diseases; IPAT = inpatient parenteral antimicrobial therapy; NR = not reported; OPAT = outpatient parenteral antimicrobial therapy.

Note: P < 0.05 is statistically significant difference between 2 groups

Appendix 7: Overlap Between Included Systematic Reviews

Please note that this appendix has not been copy-edited.

Table 18: Overlap in Relevant Primary Studies Between Included Systematic Reviews