Association of Race/Ethnicity, Inflammation, and Albuminuria in Patients With Diabetes and Early Chronic Kidney Disease

Abstract

OBJECTIVE African Americans (AAs) and Hispanics have higher diabetes and end-stage renal disease but similar or lower early chronic kidney disease (CKD) compared with whites. Inflammation plays a critical role in the pathogenesis of diabetes-related CKD. We postulated that in contrast to the general population, AAs and Hispanics have a higher prevalence of early diabetic CKD and systemic inflammatory markers compared with whites. RESEARCH DESIGN AND METHODS We analyzed the National Health and Nutrition Examination Survey 1999–2008 of 2,310 diabetic patients aged ≥20 years with fasting plasma glucose (FPG) ≥126 mg/dL. We performed multiple linear regression among patients with early CKD (urinary albumin excretion [UAE] ≥30 μg/mL and estimated glomerular filtration rate ≥60 mL/min/1.73 m2) to test the relationship between UAE and C-reactive protein (CRP) by race/ethnicity, adjusting for demographics, diabetes duration, FPG, hemoglobin A1c, uric acid, white blood cell count, medication use, cardiovascular disease, and related parameters. RESULTS In patients with diabetes, the prevalence of early CKD was greater among Hispanics and AAs than whites (P < 0.0001). AAs had higher adjusted odds ratio (AOR) for CRP ≥0.2 mg/dL (AOR 1.81 [95% CI 1.19–2.78]), and Hispanics had higher AOR for UAE ≥30 μg/mL (AOR 1.65 [1.07–2.54]). In a regression model adjusted for confounding variables, there was a significant association between UAE and CRP in the mid-CRP tertile (CRP 0.20–0.56 mg/dL, P = 0.001) and highest CRP tertile (CRP ≥0.57 mg/dL, P = 0.01) for Hispanics, but only in the mid-CRP tertile (P = 0.04) for AAs, compared with whites. CONCLUSIONS AAs and Hispanics with diabetes have a higher prevalence of early CKD compared with whites, which is significantly associated with UAE and/or CRP.