Cross-sectional population-based estimates of a rural-urban disparity in prevalence of long COVID among Michigan adults with polymerase chain reaction-confirmed COVID-19, 2020-2022.

ABSTRACT

PURPOSE: To (1) assess whether residential rurality/urbanicity was associated with the prevalence of 30- or 90-day long COVID, and (2) evaluate whether differences in long COVID risk factors might explain this potential disparity. METHODS: We used data from the Michigan COVID-19 Recovery Surveillance Study, a population-based probability sample of adults with COVID-19 (n = 4,937). We measured residential rurality/urbanicity using dichotomized Rural-Urban Commuting Area codes (metropolitan, nonmetropolitan). We considered outcomes of 30-day long COVID (illness duration ≥30 days) and 90-day long COVID (illness duration ≥90 days). Using Poisson regression, we estimated unadjusted prevalence ratios (PRs) to compare 30- and 90-day long COVID between metropolitan and nonmetropolitan respondents. Then, we adjusted our model to account for differences between groups in long COVID risk factors (age, sex, acute COVID-19 severity, vaccination status, race and ethnicity, socioeconomic status, health care access, SARS-CoV-2 variant, and pre-existing conditions). We estimated associations for the full study period (Jan 1, 2020-May 31, 2022), the pre-vaccine era (before April 5, 2021), and the vaccine era (after April 5, 2021). FINDINGS: Compared to metropolitan adults, the prevalence of 30-day long COVID was 15% higher (PR = 1.15 [95% CI 1.03, 1.29]), and the prevalence of 90-day long COVID was 27% higher (PR = 1.27 [95% CI 1.09, 1.49]) among nonmetropolitan adults. Adjusting for long COVID risk factors did not reduce disparity estimates in the pre-vaccine era but halved estimates in the vaccine era. CONCLUSIONS: Our findings provide evidence of a rural-urban disparity in long COVID and suggest that the factors contributing to this disparity changed over time as the sociopolitical context of the pandemic evolved and COVID-19 vaccines were introduced.