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J Trauma Acute Care Surg. 2019 Mar 23. doi: 10.1097/TA.0000000000002271. [Epub ahead of print]

Evaluating Mortality Outlier Hospitals to Improve the Quality of Care in Emergency General Surgery.

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Section of General Surgery, Trauma, and Surgical Critical Care Department of Surgery.
Yale Center for Analytical Sciences.
Section of Geriatrics, Department of Internal Medicine.



Expected performance rates for various outcome metrics are a hallmark of hospital quality indicators used by AHRQ, CMS, and NQF. The identification of outlier hospitals with above- and below-expected mortality for emergency general surgery (EGS) operations is therefore of great value for EGS quality improvement initiatives. The aim of this study was to determine hospital variation in mortality after EGS operations, and compare characteristics between outlier hospitals.


Using data from the California State Inpatient Database (2010-2011), we identified patients who underwent one of eight common EGS operations. Expected mortality was obtained from a Bayesian model, adjusting for both patient- and hospital-level variables. A hospital-level standardized mortality ratio (SMR) was constructed (ratio of observed to expected deaths). Only hospitals performing ≥3 of each operation were included. An "outlier" hospital was defined as having a SMR 80% confidence interval that did not cross 1.0. High- and low-mortality SMR outliers were compared.


There were 140,333 patients included from 220 hospitals. SMR varied from a high of 2.6 (mortality 160% higher than expected) to a low of 0.2 (mortality 80% lower than expected); 12 hospitals were high-SMR outliers, and 28 were low-SMR outliers. Standardized mortality was over 3 times worse in the high-SMR outliers compared to the low-SMR outliers (1.7 vs 0.5; p<0.001). Hospital-, patient-, and operative-level characteristics were equivalent in each outlier group.


There exists significant hospital variation in standardized mortality after EGS operations. High-SMR outliers have significant excess mortality, while low-SMR outliers have superior EGS survival. Common hospital-level characteristics do not explain the wide gap between under- and over-performing outlier institutions. These findings suggest that SMR can help guide assessment of EGS performance across hospitals; further research is essential to identify and define the hospital processes of care which translate into optimal EGS outcomes.


Level III Epidemiologic Study.

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