Background: Reducing geographic disparities in antibiotic prescribing is a central public health priority to combat antibiotic resistance, but the drivers of this variation have been unclear.
Methods: We measured how variation in outpatient visit rates ('observed disease') and antibiotic prescribing rates per visit ('prescribing practices') each contributed to geographic variation in per capita antibiotic prescribing in Massachusetts residents under the age of 65 between 2011 and 2015.
Results: 45.2% of the per capita antibiotic prescribing between high- and low-prescribing census tracts in Massachusetts was attributable to variation in outpatient visit rates, while 25.8% was explained by prescribing practices. Outpatient visits for sinusitis, pharyngitis, and suppurative otitis media accounted for 30.3% of the gap in prescribing, with most of the variation in visit rates concentrated in children under 10. Outpatient visits for these conditions were less frequent in census tracts with high social deprivation index.
Conclusions: Interventions aimed at reducing geographic disparities in antibiotic prescribing should target the drivers of outpatient visits for respiratory illness and should account for possible under-utilization of health services in areas with the lowest antibiotic consumption. Our findings challenge the conventional wisdom that prescribing practices are the main driver of geographic disparities in antibiotic use.
Keywords: Antibiotic prescribing; antibiotic resistance; medical claims; respiratory infection; social determinants of health.
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