A comparison of global versus disease-specific quality-of-life measures in patients with NIDDM

OBJECTIVE - This study was conducted to compare the Short Form 36 (SF-36) (a global measure of health-related quality of life) and the Diabetes Care Profile (DCP) (a diabetes-specific measure of self-care and diabetes-related quality of life) in patients with NIDDM. RESEARCH DESIGN AND METHODS - This study was conducted as part of a larger study initiated in 1991 using a randomly selected sample of communities, physicians, and patients with diabetes located throughout Michigan. A total of 255 patients with NIDDM participated. The study examined the relationship between the two measures and diabetes variables, such as glycosylated hemoglobin level and number of complications. RESULTS - The SF-36 and the DCP have both common and discrete measurement domains. Both instruments have acceptable subscale reliability The DCP has predictive validity regarding glycemic control, whereas the SF-36 does not. Both measures correlate with the number of complications for patients who have NIDDM treated with insulin. CONCLUSIONS - This study suggests that for examining relationships within diabetes, e.g., the impact of acute complications and/or regimen on quality of life, the DCP is the appropriate measure. Conversely, when examining relationships between the patient's experience of living with diabetes and quality of life and other chronic diseases, the SF-36 would be an appropriate measure. Both instruments can be used to illuminate the experience and behavior of patients living with and caring for NIDDM.