Reliability, validity and sensitivity of the Chinese (simple) Short Form 36 Health Survey version 2 (SF-36v2) in patients with chronic hepatitis B

The purpose of the study was to evaluate reliability, validity and sensitivity of the Chinese (simple) SF-36v2 in patients with chronic hepatitis B (CHB). Four hundred and sixty patients were recruited and allocated to CHB (CHB without cirrhosis) (n = 323) and CHB-related cirrhosis (n = 137) groups. Internal consistency reliability was estimated with Cronbach's α-coefficient. Convergent and discriminant validity were assessed by item-scale-component correlation. Factorial validity was explored by principal component factor analysis with varimax rotation. Sensitivity was measured with Cohen's effect size (ES), and independent sample t-test between the CHB and CHB-related cirrhosis groups and between alanine aminotransferase (ALT) normal and abnormal groups after stratifying illness stages. The results showed that Cronbach's α of the total SF-36v2 was 0.92, with the range from 0.72 to 0.87 in the eight scales and 0.76 to 0.77 in the two summary components. Most of the hypothesized item-scale-component correlations were 0.40 or over, and all of such hypothesized correlations were higher than the alternative ones, indicating satisfactory convergent and discriminant validity. Two and seven factors were extracted after varimax rotation at the scale level and item level. The eligible ES with statistically significant independent sample t-test was found in the physical component summary (PCS) and physical function (PF), role-physical (RP), general health (GH), vitality (VT), social functioning (SF) scales by comparison between CHB and CHB-related cirrhosis groups, and in the PCS and PF, GH, SF scales by comparison between the ALT normal and abnormal groups in the stratification of patients with CHB. In conclusion, the Chinese (simple) SF-36v2 has acceptable reliability, validity and sensitivity in patients with CHB.