Effect of Functional Health-Related Quality of Life on Long-Term Survival After Cardiac Surgery

Abstract

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. 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). Poor health-related quality of life after recovery from cardiac surgery identifies patients who are at risk for reduced long-term survival.