Psychometric testing of the health-related quality of life measurement, SF-36v2, in the general population of Thailand

Abstract

ABSTRACT Background: The SF-36v2 is commonly used instrument worldwide. Nevertheless, it lacks the evidence of psychometric testing and health-related quality of life (HRQoL) level among the general Thai population. Therefore, this study aimed to investigate the psychometric performance and to evaluate the HRQoL level and the factors associated with it in the general Thai population. Methods: Cross-sectional research was conducted with 600 Thai subjects. Various psychometric properties were investigated including ceiling/floor effects, item-scale and scale levels validity using correlations, principal component analysis (PCA), and internal consistency. Multiple regression was used to assess the impact of demographic factors on the HRQoL level. Results: Cronbach’s alpha ranged from 0.703 to 0.858. These eight SF-36v2 scales had a high ceiling effect while no floor effects were observed except for Bodily pain and General health. Correlations between the eight scales and two summary components, and item-scale correlations supported the hypotheses. Physical and Mental Health components were identified by PCA. Multiple regression revealed that having chronic diseases diminished HRQoL level. Conclusions: These preliminary results confirmed that the Thai SF-36v2 was a valid and reliable instrument. Having chronic diseases diminished the HRQoL level. Further study investigating subjects in different severity and impact of other factors on HRQoL level is encouraged.