Effect of functional health-related quality of life on long-term survival after cardiac surgery

Background - Health-related quality-of-life instruments have become important measures of early health outcomes after cardiac surgery. The relationship between quality of life after recovery from surgery and subsequent long-term survival has not previously been explored. Our objective was to determine whether the Duke Activity Status Index (DASI) was predictive of subsequent time-related survival after recovery from cardiac surgery. Methods and Results - We examined survival status among 6305 patients who underwent isolated coronary artery bypass grafting with or without valve procedures or isolated valve procedure between May 1995 and June 1998 who had a preoperative baseline and follow-up DASI. The postoperative DASI was administered nominally at 6 and 12 months. Baseline and perioperative variables and postoperative morbid events were prospectively collected concurrently with patient care. The end point was all-cause mortality. The Social Security Death Index was queried for survival status. Cox proportional-hazards analysis was used to study the associations between DASI, a number of traditional risk factors, and survival. Median follow-up was 8.6 years. The "dose-response" relationship between baseline and follow-up DASI and risk of long-term death was established. Follow-up DASI was associated with risk- adjusted long-term survival hazard ratio of 0.98 per unit increase (confidence limits, 0.97 to 0.98; P < 0.0001). Achieving maximum baseline DASI was associated with better risk-adjusted long-term survival (hazard ratio, 0.64; confidence limits, 0.50 to 0.83; P = 0.0005). Conclusions - Poor health-related quality of life after recovery from cardiac surgery identifies patients who are at risk for reduced long-term survival.