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.

Predicting timing of clinical outcomes in patients with chronic kidney disease and severely decreased glomerular filtration rate.

Patients with chronic kidney disease and severely decreased glomerular filtration rate (GFR) are at high risk for kidney failure, cardiovascular disease (CVD) and death. Accurate estimates of risk and timing of these clinical outcomes could guide patient counseling and therapy. Therefore, we developed models using data of 264,296 individuals in 30 countries participating in the international Chronic Kidney Disease Prognosis Consortium with estimated GFR (eGFR)s under 30 ml/min/1.73m2. Median participant eGFR and urine albumin-to-creatinine ratio were 24 ml/min/1.73m2 and 168 mg/g, respectively. Using competing-risk regression, random-effect meta-analysis, and Markov processes with Monte Carlo simulations, we developed two- and four-year models of the probability and timing of kidney failure requiring kidney replacement therapy (KRT), a non-fatal CVD event, and death according to age, sex, race, eGFR, albumin-to-creatinine ratio, systolic blood pressure, smoking status, diabetes mellitus, and history of CVD. Hypothetically applied to a 60-year-old white male with a history of CVD, a systolic blood pressure of 140 mmHg, an eGFR of 25 ml/min/1.73m2 and a urine albumin-to-creatinine ratio of 1000 mg/g, the four-year model predicted a 17% chance of survival after KRT, a 17% chance of survival after a CVD event, a 4% chance of survival after both, and a 28% chance of death (9% as a first event, and 19% after another CVD event or KRT). Risk predictions for KRT showed good overall agreement with the published kidney failure risk equation, and both models were well calibrated with observed risk. Thus, commonly-measured clinical characteristics can predict the timing and occurrence of clinical outcomes in patients with severely decreased GFR.

Socioeconomic Status and Incidence of Hospitalization With Lower-Extremity Peripheral Artery Disease: Atherosclerosis Risk in Communities Study.

BACKGROUND: Compared to coronary heart disease, heart failure, and stroke, the relationship between low socioeconomic status (SES) and peripheral artery disease (PAD) is less well established. We examined the association between SES and incidence of hospitalization with PAD and explored whether this association can be explained by traditional cardiovascular risk factors and healthcare access. METHODS AND RESULTS: A total of 12 517 participants in the Atherosclerosis Risk in Communities (ARIC) Study (1987-1989) with no prior PAD were examined. Individual-level SES was assessed from household income (low <$12 000/year, medium $12 000 to $24 999/year, and high ≥$25 000/year [double to approximate to values in 2016]) and educational attainment (high school), and area-level SES from area deprivation index (quintiles). During a median follow-up of 23.6 (Interquartile range 19.6-24.5) years, 433 participants had a hospitalization with PAD. In Cox proportional hazards regression analysis, the demographically adjusted hazard ratio was 2.42 (1.81-3.23) for low household income, 2.08 (1.60-2.69) for low educational attainment, and 2.18 (1.35-3.53) for most deprived neighborhoods, compared to their high-SES counterparts. After adjustment for traditional cardiovascular risk factors and heath care access, the associations were attenuated but remained significant, particularly for income and education. Results were consistent when stratified by race (P-values for interaction >0.2 for all SES parameters). CONCLUSIONS: Low individual- and area-level SES are strong predictors of hospitalization with PAD, in part due to increased prevalence of cardiovascular risk factors and poor access to care in these groups. Additional risk factors may also need to be identified and acted on to eliminate SES disparities in PAD hospitalization.