Socioeconomic disadvantage and the risk of advanced chronic kidney disease: results from a cohort study with 1.4 million participants

Background. Several studies have investigated the effect of socioeconomic deprivation on cardiovascular disease (CVD) and diabetes; less is known about its effect on chronic kidney disease (CKD). We aimed to measure the association between deprivation, CKD Stages 4-5 and end-stage renal disease (ESRD) in a general population sample. Methods. This observational study examined 1 405 016 participants from the English Clinical Practice Research Datalink (2000-14), linked to hospital discharge data and death certification. Deprivation was assessed according to the participant's postcode. Cox models were used to estimate hazard ratios (HRs) for CKD Stages 4-5 and ESRD, adjusting for age and sex, and additionally for smoking status, body mass index, diabetes, systolic blood pressure, prior CVD and estimated glomerular filtration rate (eGFR) at baseline. Results. During 7.5 years of median follow-up, 11 490 individuals developed CKD Stages 4-5 and 1068 initiated ESRD. After adjustment for age and sex, the HRs and confidence interval (CI) comparing those in the 20% most deprived of the population to the 20% least deprived were 1.76 (95% CI 1.68-1.84) and 1.82 (95% CI 1.56-2.12) for CKD Stages 4-5 and ESRD, respectively. Further adjustment for known risk factors and eGFR substantially attenuated these HRs. Adding our results to all known cohort studies produced a pooled relative risk of 1.61 (95% CI 1.42-1.83) for ESRD, for comparisons between highest to lowest categories of deprivation. Conclusion. Socioeconomic deprivation is independently associated with an increased hazard of CKD Stages 4-5 and ESRD, but in large part may be mediated by known risk factors.