Quantifying the Gap between Expected and Actual Rates of Antibiotic Prescribing in British Columbia, Canada.

Despite decades of stewardship efforts to combat antimicrobial resistance and quantify changes in use, the quality of antibiotic use in British Columbia (BC) remains unknown. As the overuse and misuse of antibiotics drives antibiotic resistance, it is imperative to expand surveillance efforts to examine the quality of antibiotic prescriptions. In late 2019, Canadian expected rates of antibiotic prescribing were developed for common infections. These rates were utilized to quantify the gap between the observed rates of prescribing and Canadian expected rates for antibiotic use for the province of BC. The prescribing data were extracted and matched to physician billing systems using anonymized patient identifiers from 1 January 2000 to 31 December 2018. Outpatient prescribing was further subdivided into community and emergency department settings and stratified by the following age groups: <2 years, 2-18 years, and ≥19 years. The proportions of physician visits that received antibiotic prescription were compared against the Canadian expected rates to quantify the unnecessary use for 18 common indications. Respiratory tract infections (RTI), including acute bronchitis, acute sinusitis, and acute pharyngitis, reported significant levels of overprescribing. Across all ages and health care settings, prescribing for RTI indications occurred at rates 2-8 times higher than the expected rates recommended by a group of expert Canadian physicians. Understanding the magnitude of unnecessary prescribing is a first step in delineating the provincial prescribing quality. The quantification of antibiotic overuse offers concrete targets for provincial stewardship efforts to reduce unnecessary prescribing by an average of 30% across both outpatient and emergency care settings.