Socioeconomic Inequalities Worsen the Risk of Death in CKD: A Population-Based Cohort Study in Italy

Background: Few studies have explored the impact of socioeconomic position on chronic kidney disease (CKD). This study aims to fill this gap using a large Italian cohort of CKD patients. Methods: We analyzed a cohort of incident CKD cases from the Lazio regional Health Information System from 1 January 2012 to 31 December 2021. We used the deprivation index (DI), a 5-category census-block indicator that integrates several dimensions of disadvantage. The outcomes were mortality and end-stage kidney disease (ESKD). We characterized the health status of patients in the two years before CKD identification and followed each subject from the index date to the end of follow-up, i.e., the date of the outcome, of emigration, or 31 December 2022, whichever came first. We used Cox proportional hazard models to investigate the association between DI and outcomes (HR, 95% CI). Results: From 2012 to 2021, 127,457 new cases (55.9% men) were diagnosed. The average age was 72.2 (± 13.7) for men and 74.4 (± 14.8) for women. During an average follow-up of 4.3 years (± 3.2), 57,158 patients (45%) died, and 5,994 developed ESKD (5%). The age-adjusted association between DI and mortality was higher in men than in women (p-value interaction = 0.02), HRs for the extreme categories of DI (very high vs. very low) were 1.16, 95% CI 1.12-1.21 for men, and 1.08, 95% CI 1.04-1.13, for women). There was no evidence of association between DI and ESKD. Conclusions: In this population, socioeconomic disadvantage is associated with a higher risk of death but not of ESKD in CKD patients.