Anemia as a predictor of cardiovascular events in patients with elevated serum creatinine.

Patients with anemia and patients with chronic kidney disease have elevated risks for cardiovascular disease. Available studies have been too small to provide details about the relationship or to provide for extensive covariate control. In a large insurance database with linked laboratory values, records of women with serum creatinine >1.2 mg/dl and men with serum creatinine >1.4 mg/dl, identified from July 2000 through June 2003, were sought, and the insurance claims searches for hospitalizations that were associated with myocardial infarction, coronary revascularization, unstable angina, stroke, or congestive heart failure. New onset of dialysis also was sought. Multivariate Poisson regression was used to estimate rate ratios for these events at various hemoglobin (Hb) levels, with adjustment for patient characteristics and previous event history. Among 88,657 patients with high serum creatinine, the risk for hospitalization with myocardial infarction was two to five times higher in anemic (Hb <12 g/dl) patients than in people with Hb from 12.0 to 12.9 g/dl. A similar but less dramatic pattern of higher incidence of coronary revascularization was observed with lower Hb levels. Risks for hospitalization with congestive heart failure declined regularly with increasing Hb levels from a doubling of risk at Hb <10 g/dl to a 61% decrease at 15 g/dl, both relative to 12.0 to 12.9 g/dl. The risk for progression to dialysis was only slightly elevated (7 to 34%) in anemic patients. Anemia raises the risk for cardiovascular disease in patients with elevated serum creatinine.