Does size matter? The impact of caseload and expertise concentration on AMI 30-day mortality—A comparison across 10 OECD countries

Objective To examine the variability of hospital performance within and across countries, using 30-day acute myocardial infarction (AMI) mortality, and to study the impact of hospital characteristics on performance. Study setting Hospital-level adjusted risk standardized mortality rates (RSMR) and hospital characteristics were collected from 10 OECD and two collaborating countries including 1,163 hospitals. Study design Associations between RSMR and hospital characteristics were studied using univariate and multivariate linear regressions. Clusters of hospitals were created using hierarchical clustering and mortality compared using linear regression. Findings Wide variation between countries was found for RSMR and hospital characteristics. Regression models showed large country effects. A high volume of AMI admission was associated with lower RSMR in a model using a restricted number of hospital characteristics (−0.83, p