Patterns of outpatient antibiotic prescribing in older adults by social determinants of healthcare access: a population-based retrospective cohort study

Abstract

Objectives

Strategies to improve antibiotic use may exacerbate health inequities if they do not consider existing barriers to healthcare access. We examined associations between social determinants of healthcare access (SDOH) and antibiotic prescribing and variations in these associations pre- and post-COVID-19 emergence.

Methods

We conducted a retrospective cohort study of community-dwelling adults aged ≥66 years in Ontario, Canada, between March 2018 and March 2020 (pre-pandemic period) and March 2020 and March 2022 (pandemic period). Multivariable Fine-Gray subdistribution hazard models were used to examine associations between three SDOH variables (neighbourhood-level income and proportion racialized, and individual-level recent immigration) and incident antibiotic prescriptions, accounting for mortality as a competing risk. We assessed for potential effect modification by the pandemic period.

Results

The pre-pandemic (n = 2 567 382) and pandemic (n = 2 744 337) cohorts were similar in average age (75 years). Antibiotic prescribing was slightly higher among residents in the highest income neighbourhoods in pre-pandemic (subdistribution hazard ratio [sHR], 1.03 [95% CI, 1.02–1.04], compared with lowest income) and pandemic (sHR, 1.02 [1.01–1.03]) periods. Prescribing was higher among recent immigrants (vs. long-term residents) in both periods, with a more pronounced difference observed during the pandemic (sHR, 1.21 [1.18–1.25]) than pre-pandemic (sHR, 1.12 [1.09–1.16]) period. Prescribing was lower among residents living in the most diverse neighbourhoods (vs. least diverse) in both periods, with a more pronounced difference during the pandemic (sHR, 0.81 [0.80–0.82]) than pre-pandemic (sHR, 0.92 [0.91–0.93]) period.

Discussion

SDOH variables are associated with antibiotic prescribing patterns over time among older outpatients, and the COVID-19 pandemic further modified some of these associations.