Evaluation of Complication Rates after Coronary Artery Bypass Surgery using Administrative Data

Abstract

Our objectives were (1) to determine if studying hospital complication rates after coronary artery bypass graft (CABG) surgery provides information not available when only mortality is studied, and (2) to reexplore the utility of ICD-9-CM administrative data for CABG outcomes assessment. Using data from Massachusetts, we identified CABG cohorts from 1990 and 1992 to respectively develop and validate multivariate risk adjustment models predicting in-hospital mortality and complications. The resulting models had good discrimination and calibration. In 1992, adjusted hospital complication rates ranged widely from 13.0% to 57.6%, while mortality rates ranged from 1.4% to 6.1 %. Hospitals with high complication rates tended to have high mortality (r = 0.74, P = 0.006), but 2 of the 12 hospitals studied ranked quite differently when judged by complications rather than mortality. We conclude that (1) complications after CABG occur frequently and may provide information about hospital quality beyond that obtained from hospital mortality rates, and that (2) administrative data continue to be a promising resource for outcomes research. ¹ W. Ghali is now affiliated with the University of Calgary, Calgary, Alberta, Canada; R. Hall is now affiliated with the University of Toronto, Toronto, ONT, Canada, and A. Rosen is now affiliated with the center for Health Quality, Outcomes, and Economic Research, Bedford MA, USA. ² This study was supported by the Walnut Medical Charitable Trust, Massachusetts Health Data Consortium and Alberta Heritage Foundation for Medical Research (Population Health Investigator Grant – W. A. Ghali).