The psychometric testing of the Thai version of the Health Utilities Index in patients with ischemic heart disease.

The HEALTH UTILITIES INDEX(®) (HUI(®)) is a family of systems designed to measure utility scores of health-related quality of life for comprehensive health states. There are two current HUI systems: HUI2 and HUI3. Since no Thai version of self-administered HUI was available, the study objective was to translate and test the psychometric properties of the HUI self-complete Thai-language questionnaire in terms of practicality, reliability, validity and responsiveness. A convenience sample of 216 outpatients with ischemic heart disease (IHD) was selected. Mean age was 60.3 ± 7.2 (range 37-77) and 37.2% were males. The floor and ceiling effects of the total scores for both HUI were <15%. The intraclass correlation coefficients were from moderate to high for all attributes and total scores. The correlations of HUI2 and HUI3 when compared with the EQ-5D and MacNew global scores were high (Spearman's rho > 0.5, P < 0.001). Discriminant validity was proved among three groups of different specific activity scale classes (P < 0.001). The effect size was the highest (0.92) in the patients reporting worsened health status assessed by the HUI2. In conclusion, both of the HUIs demonstrated conditionally satisfactory psychometric properties in the patients with IHD.