Beyond healthcare access: social deprivation and COVID-19 outcomes in dialysis patients in the provence-alpes-côte d’Azur region, France

Socioeconomic deprivation has been consistently associated with worse COVID-19 outcomes, yet it remains unclear whether social gradients persist in populations receiving regular, highly structured, life-sustaining care. Dialysis patients provide a specific context to explore whether structural social determinants continue to shape epidemic vulnerability beyond healthcare access alone. To assess the association between socioeconomic deprivation and both COVID-19 infection and clinical severity among dialysis patients in the Provence-Alpes-Côte d’Azur (PACA) region during the pre-vaccination period (2020). We conducted a retrospective cohort study using the REIN registry including adult dialysis patients living in PACA in 2020. Area-level deprivation was measured using the French Deprivation Index (FDep) at the IRIS level. We analysed factors associated with (i) COVID-19 infection and (ii) severe COVID-19 among infected patients using multivariable models accounting for individual characteristics, comorbidities, dialysis modality, and contextual variables. A sensitivity analysis was performed by epidemic wave to assess robustness. Higher socioeconomic deprivation was associated with increased risk of COVID-19 infection and with more severe clinical forms among infected patients, after adjustment for individual and contextual covariates. Associations were consistent across epidemic waves in sensitivity analyses, supporting the robustness of the findings. Social gradients in COVID-19 infection and severity persisted in a population benefiting from regular, continuous dialysis care, suggesting that structural social determinants (e.g. living conditions and deprivation-related vulnerabilities) play a critical role in epidemic risk. Beyond the COVID-19 pandemic, these findings provide lessons for epidemic preparedness and the management of socially vulnerable populations with chronic diseases, supporting the integration of deprivation indicators into routine care and epidemic preparedness strategies.