OBJECTIVES: Anemia is a common hematological disorder characterized by reduced hemoglobin concentration due to various causes. Conservative estimates suggest that 3.4 million individuals in the US are anemic (National Center for Health Statistics). Despite data on anemia prevalence and associated outcomes, little is known about the impact of anemia on health care utilization and costs. The National Anemia Action Council initiated this study to examine medical costs associated with anemia. METHODS: The study used retrospective administrative claims data (facility, professional, outpatient pharmacy) from MEDSTAT Group's MarketScan Databases for patients newly diagnosed with anemia, including up to 12 months follow up. Predisposing conditions were identified using ICD-9-CM diagnosis codes for chronic kidney disease (CKD), human immunodeficiency virus (HIV), rheumatoid arthritis (RA), inflammatory bowel disease (IBD), congestive heart failure (CHF), and solid tumor cancers. Descriptive analyses compared costs between anemic patients and a random sample of non-anemic patients. Comparisons were adjusted for patient gender, insurance coverage type, predisposing condition, and disease severity for each predisposing condition using ordinary least squares regression of log-transformed costs. RESULTS: Utilization and costs were significantly higher for anemic patients (p <0.0001). Average annualized per patient costs were $14,535 for anemic patients (55% outpatient; 33% inpatient) compared to $9451 for non-anemic patients (45% outpatient; 36% inpatient). Outpatient pharmacy costs averaged $1,833 for anemic patients and $1813 for non-anemic patients (p = 0.24). Significant differences persisted after adjusting for covariates. CONCLUSIONS: Medical costs of anemic patients are as much as twice those of non-anemic patients after adjusting for several potential confounders. These results suggest that anemia may be responsible for significant excess health care costs, though residual confounding may account for some of the observed differences. A large-scale treatment trial would be required to establish definitively the causal role of anemia and anemia treatment in health care utilization/costs and in medical outcomes.