Rationale & objective: Little information exists on incidence of and risk factors for chronic kidney disease (CKD) in contemporary US cohorts, and whether risk factors differ by race, sex or region in the US.
Study design: Observational cohort study.
Setting & participants: 4,198 Black and 7,799 White participants age ≥45, recruited 2003-2007 across the continental US with baseline eGFR >60 ml/min/1.73m2 and eGFR measured again ∼9 years later.
Exposures: Age, sex, race (Black/White), region (stroke belt/other), education, income, systolic blood pressure, body mass index (BMI), diabetes, coronary heart disease, hyperlipidemia, smoking, albuminuria.
Outcomes: 1) eGFR change 2) incident CKD, defined as eGFR <60 ml/min/1.73m2 and ≥40% decline from baseline or kidney failure.
Analytic approach: Linear regression and modified Poisson regression were used to determine the association of risk factors with eGFR change and incident CKD, and stratified by race, sex and region.
Results: Participants were 63±8 years old, 54% female, and 35% Black. After 9.4±1.0 years follow-up, 9% developed CKD. In an age-, sex- and race-adjusted model, Black race (β -0.13, p <0.0001) was associated with higher risk of eGFR change, but this was attenuated in the fully-adjusted model (β 0.02, p=0.54). Stroke belt residence was independently associated with eGFR change (β -0.10, p=0.0007) and incident CKD (RR 1.14 95%CI 1.01,1.30). Albuminuria was more strongly associated with eGFR change (β -0.26 vs β -0.17, pinteraction 0.01) in Black compared to White participants. Results were similar for incident CKD.
Limitations: Excluded Hispanics, unknown duration and/or severity of risk factors.
Conclusions: Established CKD risk factors accounted for higher risk of incident CKD in Black vs. White individuals. Albuminuria was a stronger risk factor for eGFR decline and incident CKD in Black compared to White individuals. Living in the US stroke belt is a novel risk factor for CKD.
Keywords: Chronic kidney disease incidence; Disparities; Race differences; Stroke belt; regional differences; risk factors.
Copyright © 2023. Published by Elsevier Inc.