Objective: Our objective was to compare the time trade-off (TTO) values of EQ-5D-3L health states elicited from Singaporeans with and without type 2 diabetes mellitus (T2DM) and T2DM patients with and without complications.
Methods: The TTO values of ten EQ-5D-3L health states were elicited from a consecutive sample of T2DM patients and a general Singaporean population sample using similar valuation protocols. In face-to-face interviews, T2DM patients and members of the general population were asked to value five and ten health states, respectively. The difference in TTO values between the two samples and between T2DM patients with and without complications was examined using multiple linear regression models.
Results: A total of 109 T2DM patients and 46 individuals without T2DM provided data. All ten health states considered, the mean TTO value was -0.02 for the general population sample and -0.04 for T2DM patients, with the unadjusted and adjusted difference being -0.06 (95 % confidence interval [CI] -0.16, 0.03) and 0.02 (95 % CI -0.12, 0.15). The general population sample had systematically lower TTO values for mild health states, with the adjusted difference being -0.13 (95 % CI -0.25, -0.02); while the two samples had similar TTO values for severe health states, with the adjusted difference being 0.02 (95 % CI -0.16, 0.19). T2DM patients without complications had systematically lower TTO values than those with complications, with the adjusted difference being -0.10 (95 % CI -0.23, 0.03).
Conclusions: It appears that diabetes and its complications affect patients' valuation of health states. Hence, the EQ-5D-3L health-state values based on the general population may underestimate the utility of health interventions for T2DM.