Utility and quality-adjusted life-years in coronary artery disease: Five-year follow-up of the MASS II trial

OBJECTIVES: This study evaluated the utility and quality-of-life year measurements for patients with coronary artery disease who underwent any of 3 therapeutic strategies with a 5-year follow-up. METHODS: Quality-of-life data were obtained from the Medicine, Angioplasty, or Surgery Study II trial. To obtain utilities, the 36-Item Short-Form questionnaire was converted to a 6-Dimensional Health State Classification System. RESULTS: Of the 611 initial patients, 579 completed the questionnaire. In all, 188 patients received the surgical treatment—194 the percutaneous, and the remaining 197 the medical. The median utility scores for the 5 years analyzed were 0.809 (95% confidence interval [CI] 0.794–0.842) for patients assigned to percutaneous coronary intervention, 0.755 (95% CI 0.723–0.774) for medical treatment, and 0.780 (95% CI 0.761–0.809) for coronary artery bypass graft surgery. The difference between percutaneous coronary intervention and medical treatment was statistically significant (P < .05, Dunn test). The median cumulative quality-of-life years across the 5 years were 3.802 (95% CI 3.668–3.936) for percutaneous, 3.540 (95% CI 3.399–3.681) for medical, and 3.764 (95% CI 3.638–3.890) for surgery. Additionally, the median quality-of-life years between percutaneous and medical treatment was 0.262 (95% CI 0.068–0.456), between surgery and medical treatment it was 0.224 (95% CI 0.036–0.413), and between surgery and percutaneous coronary intervention it was −0.038 (95% CI −0.221 to −0.146). CONCLUSION: Coronary artery bypass surgery and percutaneous coronary intervention were similar regarding cumulative quality-of-life years; however, they were both superior to that of medical treatment. The results presented are valuable data for further cost-utility studies.