Spatial accessibility to healthcare facilities and the cumulative incidence of COVID-19 infection: evidence from the reasons for geographic and racial differences in stroke (REGARDS) study, United States, March 2020 to September 2021

Objective: During the pandemic, disparities in COVID-19 infection emerged across geographic and demographic groups, potentially linked to healthcare access disparities. This study examined associations between spatial accessibility to healthcare facilities and COVID-19 incidence in the United States, among older adults in the REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort from March 2020-September 2021. Methods: Using 2020-2021 healthcare facility data for 10,089 REGARDS participants, we defined accessibility based on the presence or absence of healthcare facilities within 5 km buffers centered on participant's census tract of residence. We estimated odds ratios using Generalized Estimating Equations, adjusted for age, sex, race/ethnicity, social vulnerability index, and urbanicity. Results: The absence of certain healthcare facilities was significantly associated with higher COVID-19 infection odds: pharmacies/drugstores (OR = 1.26, 95% CI: 1.03, 1.53), retail clinics (OR = 1.19, 95% CI: 1.03, 1.38), and residential care (OR = 1.34, 95% CI: 1.11, 1.62). Sensitivity analyses using different sized buffers yielded similar results; notably, absence of health practitioner offices was significant at 1 km. Conclusions: Findings suggest that for older adults, access to healthcare facilities, especially pharmacies/drugstores, retail clinics, and residential care was inversely associated with COVID-19 infection odds. Addressing disparities in healthcare accessibility may help reduce infection risk.