To compare the discriminative power of the five-level version of the EuroQol five-dimensional questionnaire (EQ-5D-5L [5L]) and its three-level version (EQ-5D-3L [3L]) in patients with diabetes in Singapore.
Methods
A consecutive sample of patients with type 2 diabetes mellitus (T2DM) self-completed the two versions of the EQ-5D in the clinic. The 3L index score was calculated from the Singapore 3L value set, whereas the 5L index score was mapped from the 5L index score using an interim scoring. The discriminative power of the two EQ-5D indices was assessed in terms of their relative efficiency (RE) in differentiating patients with T2DM with and without one of eight clinical conditions. The efficiency of the two EQ-5D classification systems was evaluated using the Shannon’s index (H׳) and in terms of ceiling effects.
Results
A total of 121 patients with T2DM provided data for this study. The 3L score was systematically higher than the 5L score for patients with T2DM with a condition and systematically lower for the patients without a condition, with the mean differences being 0.005 and −0.011, respectively. The 5L index score showed higher RE in seven of eight clinical conditions (mean RE 1.87). The 5L classification system had higher H׳ in all dimensions: mobility (1.17 vs. 0.70), self-care (0.57 vs. 0.41), usual activities (1.01 vs. 0.72), pain/discomfort (1.47 vs. 1.02), and anxiety/depression (1.36 vs. 1.10). The overall ceiling effects decreased from 47.9% (3L) to 38.8% (5L).
Conclusions
The EQ-5D-5L is more discriminative than the EQ-5D-3L in patients with T2DM in Singapore, supporting the use of EQ-5D-5L in the population.
