Aims: To characterize and compare health-related utility in a large cohort of patients treated in hospital with diabetes and with single and multiple comorbidities.
Methods: The study was conducted in Cardiff and the Vale of Glamorgan, UK. Health-related utility was measured using the EQ5D(index), a standardized instrument for measuring health outcome. Patients from the Health Outcomes Data Repository (HODaR) were surveyed by postal questionnaire 6 weeks post discharge for in-patients and during clinics for patients attending as out-patients between January 2002 and July 2005. Patients with diabetes were identified by a previous history of in-patient admission with diabetes or as an out-patient with diabetes recorded as a coexisting diagnosis.
Results: We identified 4502 patients with diabetes. Mean ages were 65.4 and 64.2 years for males and females, respectively. Of these, 2003 (45%) had no recorded vascular complication. Overall, the EQ5D(index) was 0.584 (sd 0.325) for males and 0.533 (sd 0.351) for females. For those without any vascular complications the mean EQ5D(index) was 0.735 (sd 0.288). In a general linear model, the presence of single and multiple complications had a detrimental impact on the EQ5D(index).
Conclusion: The results of this study provide an indication of the true impact of diabetes in terms of health-related utility. There was a decrease in the mean EQ5D(index) for those with vascular complications. Economic models of diabetes that have used additive or multiplicative methods to assess utility in individuals with several complications may be unreliable, and direct measurements, such as this, are recommended.