Development and evaluation of a primary care antimicrobial stewardship program (PC-ASP) in Toronto, Ontario, Canada

Abstract

Background: Effective community-based antimicrobial stewardship programs (ASPs) are needed because 90% of antimicrobials are prescribed in the community. A primary care ASP (PC-ASP) was evaluated for its effectiveness in lowering antibiotic prescriptions for six common infections. Methods: A multi-faceted educational program was assessed using a before-and-after design in four primary care clinics from 2015 through 2017. The primary outcome was the difference between control and intervention clinics in total antibiotic prescriptions for six common infections before and after the intervention. Secondary outcomes included changes in condition-specific antibiotic use, delayed antibiotic prescriptions, prescriptions exceeding 7 days duration, use of recommended antibiotics, and emergency department visits or hospitalizations within 30 days. Multi-method models adjusting for demographics, case mix, and clustering by physician were used to estimate treatment effects. Results: Total antibiotic prescriptions in control and intervention clinics did not differ (difference in differences = 1.7%; 95% CI –12.5% to 15.9%), nor did use of delayed prescriptions (–5.2%; 95% CI –24.2% to 13.8%). Prescriptions for longer than 7 days were significantly reduced (–21.3%; 95% CI –42.5% to –0.1%). However, only 781 of 1,777 encounters (44.0%) involved providers who completed the ASP education. Where providers completed the education, delayed prescriptions increased 17.7% ( p = 0.06), and prescriptions exceeding 7 days duration declined (–27%; 95% CI –48.3% to –5.6%). Subsequent emergency department visits and hospitalizations did not increase. Conclusions: PC-ASP effectiveness on antibiotic use was variable. Shorter prescription durations and increased use of delayed prescriptions were adopted by engaged primary care providers.

A pragmatic randomized trial of a primary care antimicrobial stewardship intervention in Ontario, Canada

“…A 25% relative reduction in the total prescriptions was selected as the minimum important effect size, consistent with previously reported national goals [ 25 ]. To detect a 25% relative difference with 90% power, assuming a similar 30% antibiotic prescribing rate as in the pilot study [ 26 ], a sample size of 834 cases in each study arm was estimated, unadjusted for clustering. Visit and clinic characteristics of each group were compared using unadjusted chi-square, Fisher’s exact test or t-tests as appropriate.…”

Assessing the Validity of Electronic Medical Records for Identifying High Antibiotic Prescribers in Primary Care

“…A final diagnosis for the visit was assigned by 1 investigator (WM) using standardized coding rules developed for the study. 16 Briefly, the EMR diagnostic code was retained unless the provider diagnosis indicated an eligible condition where antibiotics might be considered (eg, EMR code—460 URI, physician diagnosis—pneumonia). In those cases, the provider clinical diagnosis was used.…”

“…The percentage of antibiotics prescribed overall and for each eligible condition (i.e., number of antibiotics per 100 visits, hereby referred to as a rate for simplicity) were produced separately using EMR diagnostic codes and the final assigned diagnosis, excluding follow up visits for the latter as clinical diagnoses were only abstracted for non-follow up visits. 16 Secondary outcomes included prescribing rates by clinic and for individual infections. The analysis also included an a priori plan to compare prescribing rates overall and by clinic, adjusting for differing infection case-mixes.…”

“…The study was a secondary analysis of a previous evaluation of a primary care antimicrobial stewardship intervention. 16 That pilot study utilized a convenience sample of 4 urban family medicine clinics in Toronto, Canada, involving 77 family physicians and 9 nurse practitioners (referred to as "providers"). The study took place in June 2016 with data collected 1 year before and after.…”

“…We examined data from a published study of primary care stewardship that included EMR codes, clinical diagnoses and antibiotic prescriptions, including delayed antibiotics. 16 The objective was to assess the validity of EMR-derived prescribing rates typically used for audit and feedback by comparing antibiotic prescribing rates based on EMR diagnostic codes with prescribing rates using the clinical diagnoses recorded by providers. In addition, we sought to assess the impact of not accounting for delayed antibiotic prescriptions on EMR-prescribing rates, as well as what effect clinical differences in patient populations between providers had on prescribing rates.…”