Background: National surveys indicate improvement in beta-blocker use after acute myocardial infarction (AMI) over time; however, these data could obscure important variation in improvement at individual hospitals. Our objective was to characterize the hospital-level variation in the improvements in beta-blocker prescription rates after AMI and to identify hospital characteristics that were associated with hospital improvement rates after adjustment for patient demographic and clinical characteristics.
Methods and results: We used data (n = 335,244 patients with AMI discharged from 682 hospitals) from the National Registry of Myocardial Infarction (NRMI) and from the American Hospital Association Annual Survey of Hospitals and hierarchical modeling to examine the associations between hospital characteristics and hospital-level rates of change in beta-blocker use during 1996-1999. On average, hospital rates of beta-blocker use for patients with AMI increased 5.9 percentage points (standard deviation, 9.7 percentage points) from the premidpoint time period (April 1996-February 1998) to the postmidpoint time period (March 1998-September 1999) of the study. The range in hospital-level changes in beta-blocker rates was substantial, from a decline of -50.0 percentage points to an increase of +35.7 percentage points. AMI volume and teaching status, geographic region, and initial beta-blocker use rates were associated with rate of improvement, but the magnitude of these effects was modest.
Conclusions: The study reveals marked hospital-level variation in improvement in beta-blocker use after AMI. Several hospital characteristics were associated with this improvement, but they are weak predictors of hospital-based improvement in the use of beta-blockers.