Social deprivation and kidney failure due to an undiagnosed nephropathy

Abstract

Background In France, kidney diseases of undetermined origin account for 5 to 20% of all causes of end-stage kidney disease. We investigated the impact of social disadvantage on the lack of aetiological diagnosis of nephropathies. Methods Data from patients who started dialysis in France between January 1, 2017, and June 30, 2018, were extracted from the French Renal Epidemiology and Information Network registry. The social deprivation of each individual was estimated by the EDI (European Deprivation Index) defined by the patient's address. Logistic regression was used to perform mediation analysis to study the potential association between social deprivation and unknown nephropathy. Results Of the 7218 patients included, 1263 (17.5%) had unknown kidney disease. A total of 394 (31.4%) patients in the unknown kidney disease belonged to the most deprived quintile of the EDI (Q5), vs. 1636 (27.5%) patients in the known kidney disease group. In the multivariate analysis, unknown kidney disease was associated with Q5 (OR 1.40 [95% CI: 1.12–1.74], p = 0.003). Mediation analysis did not identify any variables (e.g. obesity, initiation of dialysis in emergency, number of visits to the general practitioner and nephrologist before initiation of dialysis, date of first nephrology consultation) that mediated the association between social deprivation and nephropathy of unknown origin. Conclusions Our results show that, compared with nondeprived subjects, individuals experiencing social deprivation have a higher risk of unknown nephropathy at dialysis initiation. However, mediation analysis did not identify any variables that explained the association between social deprivation and nephropathy of unknown origin.