Socioeconomic status and risk of kidney dysfunction: the Atherosclerosis Risk in Communities study

BACKGROUND: There is strong evidence of an association between socioeconomic status (SES) and end-stage renal disease (ESRD). However, the association of SES with the risk of chronic kidney disease (CKD) and the rate of change in kidney function is unclear. METHODS: A cohort of 14 086 participants with an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 at baseline in the Atherosclerosis Risk in Communities study (1987-89) were studied. The association of annual household income, educational attainment and neighborhood deprivation with incident ESRD, incident CKD and change in eGFR using four measurements over ∼23 years was assessed. RESULTS: A total of 432 participants developed ESRD and 3510 developed CKD over a median follow-up time of ∼23 years. After adjustment for demographics and baseline eGFR, the hazard ratio (HR) for incident ESRD compared with the high-income group was 1.56 [95% confidence interval (CI) 1.22-1.99 in the medium-income group and 2.30 (95% CI 1.75-3.02) in the low-income group (P-trend < 0.001), and for CKD was 1.10 (95% CI 1.01-1.20) in the medium-income group and 1.30 (95% CI 1.17-1.44) in the low-income group (P-trend < 0.001). After full adjustments, the HR for ESRD was 1.33 (95% CI 1.03-1.70) in the medium-income group and 1.50 (95% CI 1.14-1.98) in the low-income group (P-trend = 0.003) and for CKD was 1.01 (95% CI 0.92-1.10) in the medium-income group and 1.04 (95% CI 0.93-1.16) in the low-income group (P-trend = 0.50). The eGFR decline was 5% and 15% steeper in the medium- and low-income groups, respectively, after full adjustment (P-trend < 0.001). Results were similar, with lower educational attainment and higher neighborhood deprivation being associated with adverse outcomes. CONCLUSIONS: SES (annual household income, educational attainment or neighborhood deprivation) was associated not only with ESRD risk but also with eGFR decline, although the association with CKD appeared weaker.