Translation and cross-cultural adaptation of the Persian version of inflammatory bowel disease-fatigue (IBD-F) self-assessment questionnaire.

Background: This study appraises the psychometrics properties of the Inflammatory bowel disease-fatigue (IBD-F) Persian version questionnaire.

Methods: The original IBD-F questionnaire was translated into the Persian version in a standard forward-back manner. The validation was performed through the face, content, and construct validity. Fifteen experts scored each item's necessity on an ordinal Likert scale of three; then, the content validity ratio was calculated using the Lawshe formula. Eight judges from pre-defined panel rated each item on an ordinal 4-point Likert scale concerning its relevancy, clarity, and simplicity for individual-CVI calculation. The mean individual-CVI was considered as the Scale-CVI for each domain. Twenty lay experts (selected from the target population) were asked to express their opinion on each item's importance by scoring on a 5-point Likert scale; subsequently, face validity was determined by the impact score formula. The questions that had minimum values of CVR, CVI, and impact score were retained in the final version of the questionnaire for reliability evaluation. Construct validity was evaluated via Confirmatory Factor Analysis. Internal consistency and test-retest reliability were checked using Cronbach's α and intraclass correlation coefficients (ICC). Fifty-four patients recruited based on inclusion and exclusion criteria to participate in the reliability analysis.

Results: All the questions received the qualified values of CVR (exceeding 0.49 points) and impact score (more than 1.5 points) and were retained in the questionnaire; however, revisions were made for questions with a CVI 0.7-0.9 for clarity and simplicity. The result demonstrated relative goodness CFA and proper internal consistency, as Cronbach's α coefficient was 0.964 for the test (0.845 and 0.963 for the first and second part of the questionnaire, respectively (and 0.888 for the re-test (0.793 and 0.876 for the first and second section of the questionnaire, respectively). The ICC values between test and re-test for the first and second part and the whole questionnaire were obtained as 0.904, 0.922, and 0.921, respectively.

Conclusion: The Persian version of the IBD-F questionnaire was valid and reliable; thus, an appropriate scale was deemed to measure fatigue (severity, frequency, and impact on daily activities).