Purpose : While the surgical volume-mortality association is well supported for certain high-risk procedures, little is known about the relationship between hospital volume and adverse events. The objective of this study was to examine the relationship between hospital volume and inpatient adverse events.
Methods: Patient Safety Indicator (PSI) were used to identify hospital-acquired adverse events in the Nationwide Inpatient Sample (NIS) database in abdominal aortic aneurysm (AAA), coronary artery bypass graft (CABG) and Roux-en-Y gastric bypass (RYNGB) from 2005 to 2008. In this observational study, volume was defined by year-specific hospital caseload for each procedure. PSI risk-adjusted rates were analyzed by volume for each procedure.
Results : Overall, hospital volume was inversely related to preventable adverse events. Higher volume hospitals had significantly lower risk-adjusted PSI rates compared to lower volume hospitals. The odds of having any adverse event, as identified through PSI software, increased linearly with a decrease in hospital volume: AAA Odds Ratio (OR): 1.016, p <.0001; CABG OR: 1.004, p<.0001; and RNYGB OR: 1.049, p<.0001 (Figure 1).
Conclusion : These data support a dose-response relationship between hospital volume and quality health care delivery in select surgical cases. This study highlights differences between hospital volume and risk-adjusted PSI rates for 3 common surgical procedures and highlights areas of focus for future studies, identifying pathways to reduce hospital-acquired events. Figure 1. Distribution of Percentage of Cases with a PSI Event for Roux-en-Y Gastric Bypass Procedures by Hospital Volume. 
See more of: The 33rd Annual Meeting of the Society for Medical Decision Making