Acute myocardial infarction and congestive heart failure outcomes at specialty cardiac hospitals

Abstract

Background: Outcomes of patients with acute myocardial infarction (AMI) and congestive heart failure (CHF) at specialty cardiac hospitals are uncertain.

Methods and results: From 2003 Medicare data, we used hierarchical regression to calculate 30-day standardized mortality ratios and risk-standardized mortality rates for AMI and CHF at 16 cardiac and 121 peer general hospitals in 15 healthcare markets. We then compared cardiac and general hospitals by determining (1) the proportion of facilities with statistically higher, no different, or lower than expected mortality based on 95% interval estimates of standardized mortality ratios and (2) differences in risk-standardized mortality rates between the types of facilities after stratification within healthcare markets. We identified 1912 patients with AMI and 1275 patients with CHF at cardiac hospitals and 13,158 patients with AMI and 18,295 patients with CHF at general hospitals. Patients at cardiac hospitals were younger, were more likely to be male, and had a much lower prevalence of noncardiovascular diseases. After adjustment for patient differences, standardized mortality ratios were significantly better than expected for 4 (25%) and 5 (31%) cardiac hospitals for AMI and CHF, respectively, compared with 5 (4%) and 6 (5%) general hospitals. Risk-standardized mortality rates were modestly lower at cardiac hospitals (15.0% versus 16.2% for AMI, P<0.001, and 10.7% versus 11.3% for CHF, P<0.01).

Conclusions: Patients with AMI and CHF at cardiac hospitals differ considerably from those at peer general hospitals. Although outcomes were modestly better at cardiac hospitals, substantial variation was noted across individual facilities.