Comparison of the Quality of Well-Being Scale and the SF-36 Results Among Two Samples of Ill Adults: AIDS and Other Illnesses

Abstract

Purpose. To compare results of using the SF-36 Short Form 36 (SF-36) and the Quality of Well-being Scale (QWB) in characterizing health outcomes over time in patients having serious illnesses, including cancer and AIDS. Background. The SF-36 and the QWB are alternative measures of health-related quality of life. The SF-36 is a morbidity measure that features a profile of nine dimensions. The QWB is a preference-based measure that combines morbidity and mortality into a single number. However, the QWB can also be scored and used as a profile. We compare SF-36 and QWB scores with different scoring methods to assess validity and sensitivity to change over time in health outcomes for adult patients with HIV infection, cancer, and other serious illnesses. Subjects. 201 adults with serious illnesses, including 99 with AIDS and 102 with cancer or other illnesses. Procedure. All subjects received both measures at baseline and at 6-month intervals thereafter, over a period of 21/2 years. Results. In the profile mode, the QWB captured outcomes that characterize the AIDS syndrome. The SF-36 differentiated between the AIDS and other illnesses patients on some scales, but without consistent direction. However, the overall QWB showed a decrease in quality of life over time for both the AIDS and other illnesses patients while the SF-36 did not. This is because many patients died and these were counted as outcomes by the QWB and as missing data by the SF-36. Conclusions. The QWB appears to be better able to capture outcomes of serious illness over time than does the SF-36.