OBJECTIVE: When ranked by inpatient pharmaceutical cost, cardiac transplantation (DRG 103) consistently appears among the top 10 DRGs in the University HealthSystem Consortium (UHC) Clinical Database. This has implications for pharmaceutical budgeting and managed care contracting. The objective of this analysis was to assess inter-institutional variability in clinical and economic outcomes as measured by pharmacy costs, length of stay and mortality among heart transplant patients in UHC's Pharmacy Clinical Database during calendar year 2000. METHODS: Eight geographically diverse academic health centers were identified retrospectively from all 20 UHC Pharmacy Clinical Database participants as having submitted at least 5 heart transplant cases during calendar year 2000. Institutions were assessed for variability in pharmacy costs, length of stay (LOS) and mortality. Data were compiled from hospital discharge summaries, Uniform Billing Version 1992 data and charge description masters. Cost data were generated from converting institution-specific charge data using a ratio of cost-to-charges (RCC). RESULTS: The total pharmaceutical cost for 232 patients from 8 institutions [range=5-96 patients/institution] was $5,083,860. Across institutions the median pharmaceutical cost per patient, median LOS per patient and total mortality rate were $11,509 (range=$5,697 - $32,763), 22 days (range=10.5days -105days), and 10.3% (range=0% - 23.5%) respectively. Cardiovascular agents (17.6%), biologic and immunologic agents (16.7%), hematological agents (16.4%) and systemic anti-infectives (10.7%) comprised over 60% of total pharmaceutical cost. Variation in percent class cost of total pharmaceutical costs among institutions were 11.9% - 28.4% in cardiovascular agents, 6.5% - 38% in biologic and immunologic agents, 7.1% - 27.5% in hematological agents, and 8.1% - 11.7% in systemic anti-infectives. CONCLUSION: There is considerable variation among institutions in pharmacy costs, length of stay and mortality. Further research into the drivers of pharmaceutical cost variation, resource utilization and clinical outcome is warranted.