Outpatient Parenteral Antibiotic Therapy

Key Messages

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.