Validation of the SF-12 among adult Kashin-Beck disease patients in Aba Tibetan autonomous area in China.

To validated the 12-item Health Status Survey (SF-12) of Chinese version for evaluating health-related quality of life (HRQL) of Kashin-Beck disease (KBD) patients in Aba Tibetan autonomous area, China. 338 adult KBD patients in Rangtang County of Aba area were investigated with SF-12. Principal component analysis with varimax rotation was used to test the original factor pattern. Internal consistency reliability was assessed by using Cronbach's alpha. "Known groups" construct validity was assessed by comparing SF-12 component scores between respondents hypothesized to differ in health-related variables. Two latent factors were extracted explaining 69.4 % of the variance of the questionnaire. The factor loadings were mostly according with the principle concept, except for "vitality" (VT) and "social functioning" (SF) scales that loaded heavier on physical component. The Cronbach's alpha coefficient was 0.909 for the physical health domain, 0.900 for the mental health domain, and 0.914 for the whole scale. The SF-12 had satisfactory "known group" validity and could well discriminate the differences between patients and healthy controls and between subgroups divided by age, duration of suffering or number of affected joints. The SF-12 could be used to evaluate the HRQL of adult KBD patients in Aba Tibetan autonomous area in China and with good feasibility, reliability and validity.