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

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.