Outpatient Antibiotic Prescribing in Massachusetts, 2011-2015

The objectives of this study were to develop methods to measure population-based outpatient antibiotic prescribing in Massachusetts and to describe the findings as a first step toward institution of ongoing surveillance.

We analyzed outpatient prescription claims from the Massachusetts All-Payers Claims Database from 2011 to 2015. We grouped claims for antibiotics according to the World Health Organization's Anatomical Therapeutic Chemical Classification System using the National Library of Medicine's RXNorm database. We grouped prescribers into 17 specialties. Antibiotic use rates were calculated, and simple frequencies were used to describe patterns.

The overall annual rate of outpatient antibiotic use for individuals aged 0-64 years was 696 prescriptions per 1000 people. During 2015, 68% of people in Massachusetts had no antibiotic prescription, and 17% had only 1 prescription. There was dramatic variability in antibiotic use rates by census tract within the state (rates of penicillin use ranged from 31 to 265 prescriptions per 1000 people, macrolides from 28 to 333, cephalosporins from 8 to 89, quinolones from 13 to 118). Antibiotic use rates were generally lower in urban census tracts. From 2011 to 2015, there was a 17% decline in antibiotic prescribing, with the greatest decline for macrolides (28%).

There was variability in antibiotic prescribing within Massachusetts by age, sex, and antibiotic class. Variation in antibiotic use across census tracts within the state was similar to the variation in use across US states. Continued measurement and detailed local population rates of antibiotic use in Massachusetts will provide feedback for local prescribers.