Validation of the Quality-of-Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO-26) in Korean population

Abstract

We aimed to evaluate the reliability and validity of the adapted Korean version of the Quality-of-Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO-26). Translation/retranslation of the English version of QUALEFFO was conducted, and all steps of the cross-cultural adaptation process were performed. The Korean version of the visual analog scale measure of pain, QUALEFFO-26 and the previously validated Short Form-36 (SF-36) were mailed to 162 consecutive patients with osteoporosis. Factor analysis and reliability assessment by kappa statistics of agreement for each item, the intraclass correlation coefficient and Cronbach's α were conducted. Construct validity was also evaluated by comparing the responses of QUALEFFO-26 with the responses of SF-36 using Pearson's correlation coefficient. Factor analysis extracted 3 factors. All items had a kappa statistics of agreement greater than 0.6. The QUALEFFO-26 showed good test/retest reliability (QUALEFFO-26: 0.8271). Internal consistency of Cronbach's α was found to be very good (QUALEFFO-26: 0.873). The Korean version of QUALEFFO-26 showed good significant correlation with SF-36 total score and with single SF-36 domains scores. The adapted Korean version of the QUALEFFO-26 was successfully translated and showed acceptable measurement properties and, as such, is considered suitable for outcome assessments in the Korean-speaking patients with osteoporosis.