OBJECTIVES:To evaluate recent dosing patterns and associated drug costs of EPO and DARB for inpatient hospital pCKD and cancer patients. METHODS: Discharge data from 518 geographically diverse hospitals were used to select cancer or pCKD patients who were admitted to the hospital between January 2003 and June 2005. Patients were included if they received EPO or DARB during the course of their inpatient stay and were excluded if diagnosed with HIV, underwent a surgical procedure, or received both EPO and DARB during the same admission. The dose only ratio was calculated as the ratio of the weighted mean EPO and DARB daily dose (units EPO: mcg DARB) with cost based on the average daily dose and 2005 wholesale acquisition cost. RESULTS: A total of 53,679 EPO and 7,669 DARB cancer patients were identified with an average daily dose of EPO 5,081 Units/day and DARB 19.7 mcg/day. This corresponded to a dose only ratio of 258:1 (Units EPO: mcg DARB) and a daily cost of EPO $62 and DARB $86. A total of 51,660 EPO and 4,522 DARB pCKD patients were identified with an average daily dose of EPO 3,253 Units/day and DARB 12.4 mcg/day. This corresponded to a dose only ratio of 262:1 and a daily cost of EPO $40 and DARB $54. CONCLUSIONS: This observational study of >117,000 inpatients demonstrated dose only ratios of approximately 260:1 in cancer and pCKD patients. Drug costs were 39% and 35% higher in the DARB group for cancer and pCKD patients, respectively. Consistent with previous observational studies in outpatients, these findings provide dose only ratios, which are seen in actual hospital practice. Awareness of these dose only ratios are of importance to health care professionals, hospital administrators, payors, and policy makers.