Cultural Adaptation,Translation and Validation of Tuberculosis Specific Health Related Quality of Life Measuring Functional Assessment of Chronic Illness Therapy Tuberculosis (FACIT-TB) Scale in Sri Lanka

The aim of the present study was to culturally adapt, translate and validate the functional assessment of chronic illness therapy tuberculosis (FACIT-TB) scale with a view to assess health related quality of life among pulmonary tuberculosis patients in Sri Lanka. The cultural adaptation was performed by Delphi method. The translation into Sinhala (the local Sri Lankan dialect) was carried out through forward–backward translation method by five translators. A multidisciplinary team of experts assessed the Sinhala FACIT-TB scale for its content validity. The construct validity, the reliability and the acceptability of the scale were determined by conducting a validation study among 225 pulmonary tuberculosis patients. The confirmatory factor analysis technique was used to assess the construct validity. The reliability was assessed through internal consistency by Cronbach’s alpha and test re- test reliability by intraclass correlation coefficient after one week of assessment. The FACIT-TB showed adequate content validity. The confirmatory factor analysis yielded high fit indices with the original five factor model of FACIT-TB: Root Mean Square Error of Approximation (RMSEA) =0.05, Standardized Root Mean Square Residual (SRMSR) =0.07, Comparative Fit Index (CFI) =0.94 and Non –Normal Fit Index (NNFI) =0.94. Reliability showed high internal consistency with Cronbach’s alpha values exceeding the Nunnally’s criteria of 0.7 and all factors of the scale showed high test-retest reliability with intra-class correlation coefficient exceeding 0.7. Overall the FACIT-TB Sinhala version showed adequate validity to assess health related quality of life among pulmonary tuberculosis patients in Sri Lanka.