Anemia and Renal Insufficiency Are Independent Risk Factors for Death among Patients with Congestive Heart Failure Admitted to Community Hospitals

A Population-Based Study

Abstract

ABSTRACT. The purpose of this retrospective cohort study was to examine the associations among chronic kidney disease, anemia, and risk of death among patients with heart failure. Retrospective cohort study. Patients with a principal diagnosis of heart failure (ICD9 codes 402.01, 402.11, 402.91, 404.01, 404.11, 404.91, and 428.xx) were included. Chronic kidney disease (CKD) was defined as a serum creatinine >1.4 mg/dl for women and >1.5 mg/dl for men. There were 665 eligible patients in the sample with a mean (SD) age of 75.7 (10.9) yr; 60% were women, 71% were white, and 38% had CKD. On admission, a hematocrit ≥40% was found for 30.3% of the patients; 22.9% had a hematocrit between 36% and 40%, 33.2% between 30% and 35%, and 13.6% had a hematocrit of <30%. The 1-yr death rates among individuals with and without CKD were 44.9% and 31.4%, respectively (relative risk [RR], 1.43; 95% confidence interval [CI], 1.17 to 1.75). The mortality at 1 yr was 31.2% for individuals with a hematocrit ≥40%; 33.8% (RR, 1.08; 95% CI. 0.79 to 1.47) for hematocrit 36 to 39%; 36.7% (RR, 1.17; 95% CI, 0.89 to 1.54) for hematocrit between 30 and 35%; and 50.0% (RR, 1.60; 95% CI, 1.19 to 2.16) for those with a hematocrit <30% (χ² for trend was 7.37; P = 0.007). Both hematocrit and serum creatinine were independently associated with increased risk of death during follow-up after controlling for other patient risk factors. In conclusion, CKD and anemia are frequent among older patients with heart failure and are independent predictors of subsequent risk of death.