Prevalence of chronic kidney disease and decreased kidney function in the adult US population: Third National Health and Nutrition Examination Survey

Background: Recently developed clinical practice guidelines and calibration of the Third National Health and Nutrition Examination Survey (NHANES III) serum creatinine assay provide a basis for estimating the prevalence and distribution of chronic kidney disease (CKD) in the United States using standardized criteria based on estimated glomerular filtration rate (GFR) and persistent albuminuria. Methods: A nationally representative sample of 15,625 noninstitutionalized adults aged 20 years and older from the NHANES III was analyzed. Kidney function (GFR), kidney damage (albuminuria), and stages of CKD (GFR and albuminuria) were estimated from calibrated serum creatinine level, spot urine albumin level, age, sex, and race. GFR was estimated using the simplified Modification of Diet in Renal Disease Study equation and compared with the Cockcroft-Gault equation for creatinine clearance (CCr). Results: The prevalence of CKD in the US adult population was 11% (19.2 million). By stage, an estimated 5.9 million individuals (3.3%) had stage 1 (persistent albuminuria with a normal GFR), 5.3 million (3.0%) had stage 2 (persistent albuminuria with a GFR of 60 to 89 mL/min/1.73 m(2)), 7.6 million (4.3%) had stage 3 (GFR, 30 to 59 mL/min/1.73 m2), 400,000 individuals (0.2%) had stage 4 (GFR, 15 to 29 mL/min/1.73 m(2)), and 300,000 individuals (0.2%) had stage 5, or kidney failure. Aside from hypertension and diabetes, age is a key predictor of CKD, and 11% of individuals older than 65 years without hypertension or diabetes had stage 3 or worse CKD. Compared with GFR estimates, CCr estimates showed a steeper decline with age and were lower in non-Hispanic blacks. Conclusion: CKD is common and warrants improved detection and classification using standardized criteria to improve outcomes.