Abstract 13760: Prior Hospital Mortality Rate is More Important than Surgical Volume in Predicting Future Congenital Heart Surgery Mortality
Introduction: With the goal of improving outcomes following congenital heart surgery, recent efforts to establish evidence-based guidelines for location of referral for congenital heart surgery have often used hospital surgical volume to determine centers of excellence. However, these efforts have largely ignored a hospital's past standardized in-hospital mortality ratio (SMR).
Hypothesis: Prior hospital SMR is a better predictor of future in-hospital congenital heart surgery mortality than hospital surgical volume.
Methods: We used the Pediatric Health Information Systems database to: 1) calculate hospital surgical volume and SMR (SMR=observed number of deaths/expected number of deaths adjusted for surgery type) for January 2004-June 2006 for children (0-18y) following congenital heart surgery at 38 hospitals, and 2) use these calculated values to predict in-hospital mortality during July 2006-December 2008. We constructed Poisson regression models to estimate risk of mortality, adjusting for age, race, sex, insurance type, and surgery type (using the Risk Adjustment in Congenital Heart Surgery [RACHS] method). We also performed stratified analysis by RACHS category.
Results: There were 49,792 hospital encounters during 2004-2008 for pediatric congenital heart surgery, with an overall in-hospital mortality of 3.45%. During January 2004-June 2006, hospital surgical volume ranged from 9 to 1555 encounters (median 530), and SMR ranged from 0.49 to 3.22 (median 0.99). For the 24,757 encounters during July 2006-December 2008, prior hospital SMR was a significant predictor of post-operative in-hospital mortality (p<0.0001), but prior hospital surgical volume was not. On stratified analysis, past SMR was predictive of mortality for RACHS categories 2, 3, and 4 (p=0.0152, 0.0353, and 0.0004, respectively), but not for categories 1 or 5/6. Hospital surgical volume was not a significant predictor of mortality for any RACHS category.
Conclusions: These data suggest that past in-hospital mortality is more important than hospital surgical volume in predicting future risk of mortality following congenital heart surgery. Public availability of in-hospital mortality data may help to identify congenital heart surgery centers of excellence.
- © 2010 by American Heart Association, Inc.