Risk Factors for Incident CKD in Black and White Americans: The REGARDS Study

Katharine L Cheung; Deidra C Crews; Mary Cushman; Ya Yuan; Katherine Wilkinson; D Leann Long; Suzanne E Judd; Michael G Shlipak; Joachim H Ix; Alexander L Bullen; David G Warnock; Orlando M Gutiérrez

doi:10.1053/j.ajkd.2022.11.015

Risk Factors for Incident CKD in Black and White Americans: The REGARDS Study

Am J Kidney Dis. 2023 Jan 5;S0272-6386(23)00005-7. doi: 10.1053/j.ajkd.2022.11.015. Online ahead of print.

Authors

Affiliations

¹ Larner College of Medicine at The University of Vermont, Division of Nephrology. Electronic address: klcheung@med.uvm.edu.
² Johns Hopkins University, Division of Nephrology.
³ Larner College of Medicine at The University of Vermont, Department of Medicine.
⁴ University of Alabama at Birmingham, School of Public Health.
⁵ Larner College of Medicine at The University of Vermont.
⁶ University of California San Francisco, Division of Nephrology.
⁷ University of California San Diego, Division of Nephrology.
⁸ University of Alabama at Birmingham, Division of Nephrology.

PMID: 36621640
DOI: 10.1053/j.ajkd.2022.11.015

Abstract

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, p_interaction 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.

Abstract

Grant support