Operative mortality and procedure volume as predictors of subsequent hospital performance.
BACKGROUND
Despite growing interest in evidence-based hospital referral for selected surgical procedures, there remains considerable debate about which measures should be used to identify high-quality providers.


OBJECTIVE
To assess the usefulness of historical mortality rates and procedure volume as predictors of subsequent hospital performance with different procedures.


METHODS
Using data from the national Medicare population, we identified all U.S. hospitals performing one of 4 high-risk procedures between 1994 and 1997. Hospitals were ranked and grouped into quintiles according to 1) operative mortality (adjusted for patient characteristics) and 2) procedure volume.


METHODS
Risk-adjusted operative mortality in 1998 to 1999.


RESULTS
Although historical mortality and volume both predicted subsequent hospital performance, the predictive value of each varied by procedure. For coronary artery bypass graft surgery, mortality rates in 1998 to 1999 differed by 3.3% across quintiles of historical mortality (3.6% to 6.9%, best to worst quintile, respectively), but only by 1.0% across volume quintiles (4.8% to 5.8%). In contrast, for esophagectomy, mortality rates in 1998 to 1999 differed by 12.5% across volume quintiles (7.5% to 20.0%, best to worst quintile, respectively), but only by 1.5% across quintiles of historical mortality (11.4% to 12.9%). Historical mortality and procedure volume had comparable value as predictors of subsequent performance for pancreatic resection and elective abdominal aortic aneurysm repair. Our findings were similar when we repeated the analysis using data from later years.


CONCLUSIONS
Historical measures of operative mortality or procedure volume identify hospitals likely to have better outcomes in the future. The optimal measure for selecting high-quality providers depends on the procedure.
Michigan Surgical Collaborative for Outcomes Research and Evaluation, M-SCORE, Department of Surgery, University of Michigan, Ann Arbor, USA. jbirkmey@med.umich.edu
John D
JD
Birkmeyer
Justin B
JB
Dimick
Douglas O
DO
Staiger
D000368:Aged; D017052:Hospital Mortality / Q000639:trends*; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D017063:Outcome Assessment, Health Care; D012189:Retrospective Studies; D013514:Surgical Procedures, Operative / Q000401:mortality*; D014481:United States / Q000453:epidemiology