OBJECTIVES: 1) To understand the prevalence of anemia among hospital inpatients with selected chronic diseases; and 2) to evaluate current anemia treatment strategy in acute care hospitals. METHODS: Using Premier's PerspectiveTM Comparative database, the largest US hospital database, all inpatients discharged between January, 2003 and December, 2003 with a primary diagnosis of chronic kidney disease, congestive heart failure, diabetes, cancer, AIDS, and rheumatoid arthritis were retrieved. Anemia was identified using ICD codes (280-285). Patient demographics, insurance type, institution characteristics, severity, and anemic treatment patterns were examined. Outcomes variables included length of stay, total cost, and in-hospital mortality. RESULTS: Of 300,494 subjects, close to a quarter (23.5%) were diagnosed with anemia. Prevalence rates varied by disease from 46.1% (chronic renal insufficiency) to 20.2% (diabetes). Only 20.4% anemics received epoetin alfa and 13.7% received iron supplement. Anemic patients were associated with longer length of stay (4.9 vs. 7.6 days, P<0.01), higher total hospitalization cost ($8014 vs. $11,752, P<0.01) and elevated in-hospital mortality (4.3% vs. 6.1%). CONCLUSIONS: Anemia is associated with many chronic diseases among acute care inpatient populations. It is often under-treated with less than one third of the anemic patients receiving readily available drugs. When left untreated anemia can be associated with suboptimal clinical and economic outcomes.