Change in health status (EQ-5D) over 5 years among individuals with and without type 2 diabetes mellitus in the SHIELD longitudinal study

BACKGROUND Health-related quality of life studies among adults with type 2 diabetes mellitus, using the EQ-5D, have been short term and have not assessed change over years. This study assessed the change in health status and health-related quality of life over 5 years among individuals with and without diabetes. METHODS Respondents to the US Study to Help Improve Early evaluation and management of risk factors Leading to Diabetes (SHIELD) completed the EuroQol-5D (EQ-5D) at baseline (2004) and 5 years later (2009). Visual analog scale (VAS) score and health index score were computed at baseline and year 5, and the change over 5 years was measured for individuals with type 2 diabetes mellitus (T2DM) and those without diabetes, and T2DM adults with and without diabetic complications. Linear regression models were used to determine change in EQ-5D score, controlling for age, gender, race, education, household income, and body mass index (BMI). RESULTS There was significantly greater decline in the EQ-5D index score in the T2DM group (-0.031 [SD 0.158]), compared with those without diabetes (-0.016 [0.141], p = 0.001). Compared with respondents without diabetes, those with T2DM had a larger reduction in EQ-5D index score, after controlling for demographics (p = 0.001). EQ-5D VAS score declined over 5 years for both groups: -1.42 (18.1) for the T2DM group, and -0.63 (15.8) for the group without diabetes, but the between-group difference was not significant either before (p = 0.09) or after (p = 0.12), controlling for demographics. T2DM respondents with diabetic complications had a greater decline in EQ-5D scores than T2DM respondents without complications (p < 0.05). CONCLUSION Over a 5-year period, health status of respondents with T2DM declined significantly compared with those with no diabetes, indicating that the burden of the disease has a long-term detrimental impact. This decline in health status is likely to impact utility scores (fewer quality-adjusted life years) for economic evaluations.