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.