A vision ‘bolt-on’ increases the responsiveness of EQ-5D: preliminary evidence from a study of cataract surgery

(1) To evaluate the effect of adding a vision dimension (‘bolt-on’) to the 5-level EQ-5D (EQ-5D-5L) and 3-level EQ-5D (EQ-5D-3L) on their responsiveness, and (2) to compare the responsiveness of a vision ‘bolt-on’ EQ-5D-3L (EQ-5D-3L + V) with SF-6D and Health Utilities Index Mark 3 (HUI3) to the benefit of cataract surgery. Sixty-three patients were assessed before and after their cataract surgery using the EQ-5D-3L, EQ-5D-5L, SF-6D, HUI3, as well as a 3-level and a 5-level vision dimension. Preference-based indices were calculated using available value sets for EQ-5D-3L, EQ-5D-3L + V, EQ-5D-5L, SF-6D, and HUI3, and non-preference-based indices were calculated using the sum-score method for EQ-5D-5L and EQ-5D-5L + V (vision bolt-on EQ-5D-5L). Responsiveness was assessed using the standardized response mean (SRM) and F-statistic. Among preference-based indices, mean changes from pre to post-surgery in EQ-5D-3L + V and EQ-5D-3L indices were 0.031 and 0.018, respectively. The mean changes for EQ-5D-5L, SF-6D and HUI3 indices were 0.020, 0.012 and 0.105, respectively. The SRM (F-statistic) for EQ-5D-3L + V and EQ-5D-3L indices were 0.458 (13.2) and 0.098 (0.6), respectively. The responsiveness of EQ-5D-3L + V was better than EQ-5D-5L, SF-6D; the responsiveness of HUI3 was better than all other measures. Using non-preference-based indices, mean change for EQ-5D-5L + V and EQ-5D-5L were 0.067 and 0.017, respectively. The corresponding SRM (F-statistic) were 0.709 (31.7) and 0.295 (5.4). Preliminary evidence from our study suggests that a vision ‘bolt-on’ may increase the responsiveness of EQ-5D-3L and EQ-5D-5L to change in health outcomes experienced by patients undergoing cataract surgery. In absence of the preference-based vision bolt-on EQ-5D-5L index, HUI3 was the most responsive measure.