Health-related quality of life as a predictor of mortality following coronary artery bypass graft surgery

Context: Health-related quality of life has not been evaluated as a predictor of mortality following coronary artery bypass graft (CABG) surgery. Evaluation of health status as a mortality predictor may be useful for preoperative risk stratification. Objective: To determine whether the Physical and Mental Component Summary scores from the preoperative Short- Form 36 (SF-36) health status survey predict mortality following CABG surgery after adjustment for known clinical risk variables. Design: Prospective cohort study conducted between September 1992 and December 1996. Setting: Fourteen Veterans Affairs hospitals. Patients: Of the 3956 patients undergoing CABG surgery only and who were enrolled in the Processes, Structures, and Outcomes of Care in Cardiac Surgery study, the 2480 who completed a preoperative SF-36. Main Outcome Measure: All-cause mortality within 180 days after surgery. Results: A total of 117 deaths (4.7%) occurred within 180 days of CABG surgery. The Physical Component Summary of the preoperative SF-36 was a statistically significant risk factor for 6-month mortality after adjustment for known clinical risk factors for mortality following CABG surgery. In multivariate analysis, a 10-point lower SF-36 Physical Component Summary score had an odds ratio (OR) of 1.39 (95% confidence interval [CI], 1.11-1.77; P = .006) for predicting mortality. The SF-36 Mental Component Summary score was not associated with 6-month mortality in multivariate analyses (OR, 1.09; 95% CI, 0.92-1.29; P=.31). Conclusions: The Physical Component Summary score from the preoperative SF- 36 is an independent risk factor for mortality following CABG surgery. The baseline Mental Component Summary score does not appear to be predictive of mortality. Preoperative patient self-report of the physical component of health status may be helpful for risk stratification and clinical decision making for patients undergoing CABG surgery.