Risk Factors for Rapid Kidney Function Decline Among African Americans: The Jackson Heart Study (JHS).

BACKGROUND

Racial differences in rapid kidney function decline exist, but less is known regarding factors associated with rapid decline among African Americans. Greater understanding of potentially modifiable risk factors for early kidney function loss may help reduce the burden of kidney failure in this high-risk population.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS: 3,653 African American participants enrolled in the Jackson Heart Study (JHS) with kidney function data from 2 of 3 examinations (2000-2004 and 2009-2013). Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine using the CKD-EPI creatinine equation.

PREDICTORS

Demographics, socioeconomic status, lifestyle, and clinical risk factors for kidney failure.

OUTCOMES

Rapid decline was defined as a ≥30% decline in eGFR during follow-up. We quantified the association of risk factors with rapid decline in multivariable models.

MEASUREMENTS

Clinical (systolic blood pressure and albuminuria [albumin-creatinine ratio]) and modifiable risk factors.

RESULTS

Mean age was 54±12 (SD) years, 37% were men, average body mass index was 31.8±7.1kg/m(2), 19% had diabetes mellitus (DM), and mean eGFR was 96.0±20mL/min/1.73m(2) with an annual rate of decline of 1.27mL/min/1.73m(2). Those with rapid decline (11.5%) were older, were more likely to be of low/middle income, and had higher systolic blood pressures and greater DM than those with nonrapid decline. Factors associated with ≥30% decline were older age (adjusted OR per 10 years older, 1.51; 95% CI, 1.34-1.71), cardiovascular disease (adjusted OR, 1.53; 95% CI, 1.12-2.10), higher systolic blood pressure (adjusted OR per 17mmHg greater, 1.22; 95% CI, 1.06-1.41), DM (adjusted OR, 2.63; 95% CI, 2.02-3.41), smoking (adjusted OR, 1.60; 95% CI, 1.10-2.31), and albumin-creatinine ratio > 30mg/g (adjusted OR, 1.55; 95% CI, 1.08-1.21). Conversely, results did not support associations of waist circumference, C-reactive protein level, and physical activity with rapid decline.

LIMITATIONS

No midstudy creatinine measurement at examination 2 (2005-2008).

CONCLUSIONS

Rapid decline heterogeneity exists among African Americans in JHS. Interventions targeting potentially modifiable factors may help reduce the incidence of kidney failure.