ORIGINAL ARTICLE Are Mortality Rates for Different Operations Related? Implications for Measuring the Quality of Noncardiac Surgery

procedure-specific mortality rates is unreliable because of small sample sizes at individual hospitals. Statistical power can be im-proved by combining mortality data from multiple operations. We sought to determine whether this approach would still be useful in understanding performance with individual procedures. Methods: We studied 11 high-risk operations performed in the na-tional Medicare population (1996–1999). For each operation, we cal-culated 1) the risk-adjusted mortality rate for the procedure and 2) the mortality rate with up to 10 other operations combined (“other ” mor-tality). To test for an association between these mortality rates, we calculated the correlation coefficient adjusting for random variation.We then collapsed hospitals into quintiles of other mortality and calculated procedure-specific mortality rates within each of these quintiles. Results: Mortality with specific operations was modestly correlated with other mortality: coefficients ranged from 0.14 for pneumonec-tomy to 0.35 for esophagectomy. Despite small to moderate corre-lations, other mortality was a good predictor of procedure-specific mortality for 10 of the 11 operations. Pancreatic resection had the strongest relationship, with procedure-specific mortality rates at hospitals in the worst quintile of other mortality 3-fold higher than those in the best quintile (15.2 % vs. 6.3%, P 0.001). Pneumo-nectomy had the weakest relationship with no significant relation-ship between other mortality and procedure-specific mortality. Conclusions: Hospitals with low mortality rates for 1 operation tend to have lower mortality rates for other operations. These relation-ships suggest that different operations share important structures and processes of care related to performance. Future efforts aimed at predicting procedure-specific performance should consider incorpo-rating data from other operations at that hospital