Chronic kidney disease (CKD),
anemia, and declining kidney function are recognized as risk factors for adverse outcomes in patients with
heart failure. This analysis was conducted to evaluate whether
anemia is a risk factor for kidney function decrease in patients with
heart failure. Data from the Studies of
Left Ventricular Dysfunction (SOLVD), a randomized trial of
enalapril versus placebo in patients with ejection fractions <or=35%, were analyzed. After randomization,
creatinine measurements were taken at 2 weeks, 6 weeks, 4 months, and every 4 months thereafter. The glomerular filtration rate (GFR) was estimated using the Modification of Diet in Renal Disease Study (MDRD) equation, and GFR slope was calculated. "Rapid decrease" was defined as a decrease in the GFR of >or=6 ml/min/1.73 m(2)/year.
Anemia was defined as baseline hematocrit <36%. Multivariate logistic regression weighted by the number of GFR assessments was used to test the relation between
anemia and rapid decrease. We also evaluated whether CKD (baseline GFR </=60 ml/min/1.73 m(2)) modified the relation between
anemia and rapid decrease. In the 6,360 subjects, the mean age was 59 years, 31% had CKD, and 6% had
anemia. Median follow-up was 2 years. In multivariate analysis,
anemia was associated with a 1.30 increased odds (95% confidence interval 1.18 to 1.45) of rapid decrease in GFR. In subjects with CKD,
anemia was associated with a 1.71 increased odds (95% confidence interval 1.43 to 2.05) of rapid decrease, while in subjects without CKD,
anemia was associated with a 1.16 increased odds (95% confidence interval 1.03 to 1.31) of rapid decrease (p for interaction <0.001). In conclusion,
anemia is associated with a rapid decrease in kidney function in patients with
heart failure, particularly in those with underlying CKD.