Utility of EQ-5D to Assess Patients Undergoing Cataract Surgery

Abstract

To assess the construct validity and responsiveness of the EuroQoL-5D (EQ-5D) instrument in Asian patients undergoing cataract surgery in Singapore. In this prospective study, English- or Chinese-speaking patients (n = 216) completed the EQ-5D and the VF-14 questionnaires before and 3 months after they underwent cataract surgery. The impact of cataracts on patients was assessed using two standard gamble (SG) questions before surgery. Construct validity of the EQ-5D index and the visual analog scale (VAS) was assessed by examining their correlation with the VF-14 and SG scores. Responsiveness of the EQ-5D was compared with that of the VF-14 in terms of the magnitude of score change associated with cataract surgery. We found that the EQ-5D index correlated with VF-14, SG (death), and SG (blindness) (Pearson r = 0.30, 0.23 and 0.24, respectively; p < 0.01). In contrast, we found no correlation between the EQ-VAS, VF-14, and SG scores. The mean EQ-5D index (difference, 0.06; effect size, 0.35) and VF-14 score (difference, 1.75; effect size, 0.97) of patients improved after cataract surgery (p < 0.0001). Our study demonstrated that the EQ-5D utility index is a valid and responsive outcome measure for evaluating the impact of cataract surgery in our Asian population. However, the implications of using the generic EQ-5D instrument to assess the cost-effectiveness of surgical interventions for visual impairment require further investigation.