Diabetes, hemoglobin A1c, cholesterol, and the risk of moderate chronic renal insufficiency in an ambulatory population

Moderate chronic renal insufficiency is common, with 12.5 million individuals in the United States estimated to have a creatinine clearance less than 50 mL/min/1.73 m(2). Little is known about the risk factors for moderate chronic renal insufficiency. We studied 1,428 subjects with Cockcroft-Gault-estimated creatinine clearances greater than 70 mL/min in a hospital-based ambulatory population. Over a mean of 5.7 +/- 1.3 years, 86 subjects developed moderate chronic renal insufficiency, defined as a decrease in creatinine clearance to less than 60 mL/min (1.1 case/100 person-years). Risk factors for moderate chronic renal insufficiency were identified using a proportional hazards model controlling for age, sex, race, systolic blood pressure, and angiotensin-converting enzyme (ACE) inhibitor use. The risk for developing moderate chronic renal insufficiency was associated with diabetes mellitus (relative risk, 2.1; 95% confidence interval [CI], 1.3 to 3.3) and elevated hemoglobin Al, levels. Compared with subjects with normoglycemia (hemoglobin A(1c) less than or equal to 5.7%), the relative risk for moderate chronic renal insufficiency for patients in the upper quartile of hemoglobin Al, (>9.0%) was 2.7 (95% CI, 1.4 to 5.1), The development of moderate chronic renal insufficiency was also independently predicted by elevated maximum serum cholesterol level. Compared with subjects with maximum cholesterol levels of 250 mg/dL or less, the relative risk for those with maximum cholesterol levels greater than 350 mg/dL was 2.4 (95% CI, 1.1 to 5.2). Similar relative risks were obtained when moderate chronic renal insufficiency was defined by the development of an increase in serum creatinine level. Hypercholesterolemia was also associated with moderate chronic renal insufficiency among persons without diabetes. In conclusion, the risk for developing moderate chronic renal insufficiency is increased by diabetes and elevated hemoglobin Al, and serum cholesterol levels. Modification of these risk factors may decrease the incidence of moderate chronic renal insufficiency. (C) 2000 by the National Kidney Foundation, Inc.