Adverse event rates as measures of hospital performance

Adverse event or complication rates are increasingly advocated as measures of hospital quality and performance. Objective of this study is to analyse patient-complexity adjusted adverse events rates to compare the performance of hospitals in Victoria, Australia. We use a unique hospital dataset that routinely records adverse events which arise during the admission. We identify hospitals with below or above average performance in comparison to their peers, and show for which types of hospitals risk adjusting makes biggest difference.

We estimate adverse event rates for 87,790 elective and 43,771 emergency episodes in 34 public hospitals over the financial year 2005/06 with a complementary log-log model, using patient level administrative hospital data and controlling for patient complexity with a range of covariates.

Teaching hospitals have average risk-adjusted adverse event rates of 24.3% for elective and 19.7% for emergency surgical patients. Suburban and rural hospitals have lower rates of 17.4% and 17%, and 16.1% and 15.7%, respectively. Selected non-teaching hospitals have relatively high rates, in particular hospitals in rural and socially disadvantaged areas. Risk adjustment makes a significant difference to most hospitals.

We find comparably high adverse events rates for surgical patients in Australian hospitals, possibly because our data allow identification of a larger number of adverse events than data used in previous studies. There are marked variations in adverse event rates across hospitals in Victoria, even after risk adjusting. We discuss how policy makers could improve quality of care in Australian hospitals.