Translation, cultural adaptation and validation of the English “Short form SF 12v2” into Bengali in rheumatoid arthritis patients

BACKGROUND To develop a culturally adapted and validated Bengali Short Form SF 12v2 among Rheumatoid arthritis (RA) patients. METHODS The English SF 12v2 was translated, adapted and back translated into and from Bengali, pre-tested by 60 patients. The Bengali SF 12v2 was administered twice with 14 days interval to 130 Bangladeshi RA patients. The psychometric properties of the Bengali SF 12v2 were assessed. Test-retest reliability was assessed by intra-class correlation coefficient (ICC) and Spearman's rank correlation coefficient and internal consistency by Cronbach's alpha. Content validity was assessed by index for content validity (ICV) and floor and ceiling effects. To determine convergent and discriminant validity a Bengali Health Assessment Questionnaire (B-HAQ) was used. Factor analysis was done. RESULTS The Bengali SF 12v2 was well accepted by the patients in the pre-test and showed good reliability. Internal consistency for both physical and mental component was satisfactory; Cronbach's alpha was 0.9. ICC exceeded 0.9 in all domains. Spearman's rho for all domains exceeded 0.8. The physical health component of Bengali SF 12v2 had convergent validity to the B-HAQ. Its mental health component had discriminant validity to the B-HAQ. The ICV of content validity was 1 for all items. Factor analysis revealed two factors a physical and a mental component. CONCLUSIONS The interviewer-administered Bengali SF 12v2 appears to be an acceptable, reliable, and valid instrument for measuring health-related quality of life in Bengali speaking RA patients. Further evaluation in the general population and in different medical conditions should be done.