Discussion

Several national organizations have published OPAT guidelines, ^{Reference Norris, Shrestha and Allison1,Reference Chapman, Patel, Horner, Gilchrist and Seaton6} including a recent review of antimicrobial stewardship opportunities within OPAT programs. ^{Reference Mahoney, Childs-Kean, Khan, Rivera, Stevens and Ryan7} Furthermore, the IDSA OPAT E-handbook highlights areas that utilize the education and expertise of pharmacists. These include antimicrobial selection, administration, duration of therapy, allergy assessment, laboratory and safety monitoring, pharmacokinetic or pharmacodynamic dosing, antimicrobial stewardship principles, and patient or caregiver counseling. ^{Reference Shah and Norris8} Recent practice surveys of OPAT physicians indicated that ∼60% of clinics have some sort of pharmacist involvement. ^{Reference Hamad, Lane, Beekmann, Polgreen and Keller4} Additionally, one small study demonstrated the inclusion of a pharmacist into an OPAT clinic has been associated with adherence to ID guidelines. ^{Reference Chung, Beeler, Muloma, Osterholzer, Damer and Erdman9}

In this survey, OPAT pharmacists performed a wide variety of activities, mostly focusing on clinical aspects. However, what OPAT pharmacists valued as important for OPAT practice did not entirely align with the functions they were performing. OPAT pharmacists were frequently ordering or reaching out for outstanding safety laboratories, but they did not place as high value in this. Although timely laboratory monitoring has been shown to contribute to overall OPAT care, ^{Reference Huck, Ginsberg, Gordon, Nowacki, Rehm and Shrestha10} the unspecialized nature of the task may explain its relatively lower ranking. OPAT pharmacists also placed lesser importance on documentation in the electronic health record. Clear communication is a vital component of successful OPAT programs, and certain aspects of documentation can be automated or templated. Likewise, OPAT pharmacists indicated the high importance of reviewing and selecting the OPAT regimen prior to hospital discharge. However, only ∼60% of OPAT pharmacists were performing these activities. Pharmacists maintain a robust knowledge of antimicrobial properties, including spectrum of activity, pharmacodynamic and alternative dosing strategies, and infusion device modalities. Pharmacists are optimally poised for designing regimens more likely to achieve patient adherence. If able, thoughtful OPAT program redesign should maximize these activities and leverage pharmacists’ strengths.

Interestingly, respondents listed that only 10% of patients were on COpAT. With recent publications showing noninferiority of oral to intravenous regimen one might expect to see more oral regimen utilized, especially if the regimen is being designed by an ID-trained pharmacist and the ongoing coronavirus disease 2019 (COVID-19) pandemic. ^{Reference Li, Rombach and Zambellas11–Reference Rivera, Mahoney, Stevens and Abu Saleh13} A likely explanation is that these patients are not followed or followed less frequently by the OPAT team. Notably, some data suggest that an increased rate of adverse drug events with oral regimens that pharmacists are suited to manage. ^{Reference Azamgarhi, Shah and Warren14,Reference Vollmer, Rivera and Stevens15} Further research may be warranted to better elucidate this trend.

A new finding from this survey includes the establishment of a benchmark of OPAT pharmacist staffing (FTE) to patient ratio. The survey results reported a median of 0.6 OPAT pharmacist FTE and a median of 43 active patients receiving OPAT. Therefore, we propose a ratio of 1 OPAT pharmacist FTE for every 45–70 patients on OPAT.

Although this is the largest survey of pharmacists practicing in OPAT, there are still many unknowns. Moreover, 27 pharmacists responded that they had OPAT practices. Coupled with programs associated with author institutions, at least 30 pharmacists within the United States have OPAT practices. Also, 118 physicians indicated formal OPAT teams. This could mean that many programs exist without formal pharmacist involvement, indicating an opportunity for growth in the United States, or that the target audience are not members of the ACCP ID PRN, which requires a paid membership. Alternatively, survey participation may have been low due to competing priorities, (eg, COVID-19 response). To facilitate networking and growth, an OPAT pharmacist contact directory has been started, and interested pharmacists can contact the authors for addition. As the inclusion of pharmacists in OPAT services grows, concerted efforts should be made to include pharmacists in multidisciplinary practice surveys.

Expansion of pharmacist involvement in OPAT may be mutually beneficial in advancement of pharmacists’ practice and work shifting or sharing with professional colleagues (physicians, advanced practice providers). Although collaborative practice agreements or license extension agreements may facilitate OPAT work, only 63% of those working in OPAT reported using either of those in their practice. Pharmacist OPAT participation may occur within the usual allowances of pharmacists’ licensure.

Pharmacist involvement in OPAT is an emerging trend within many different types of OPAT programs. Tasks performed by OPAT pharmacists varied significantly, and most commonly, clinical (nondispensing) functions are being performed. We propose a ratio of 1 OPAT pharmacist FTE for every 45–70 patients receiving OPAT. Opportunity exists for further expansion of pharmacists in OPAT programs.