Thai-version Migraine Disability Assessment (MIDAS) questionnaire: concurrent validity, test-retest reliability, internal consistency, and factors predictive for migraine-related disability

Background: A Thai-version of the Migraine Specific Quality of Life Questionnaire (MSQ 2.1) is available, but a qualified questionnaire used specifically for disability assessment was not available. The most relevant practical disability assessment tested during this study was the Migraine Disability Assessment (MIDAS) Questionnaire. Objectives: To test the concurrent validity, test-retest reliability, and internal consistency of a Thai-version MIDAS questionnaire, and factors to predict disability in people with migraine. Methods: We conducted the present prospective study at a tertiary care teaching hospital in Bangkok. The original English MIDAS Questionnaire was translated into Thai with back-translation into English and the language equivalence was assessed. The Thai-version MIDAS Questionnaire was tested for concurrent validity, test-retest reliability, and internal consistency, and factors including duration of migraine history, migraine characteristics, and comorbidity were assessed for the ability to predict migraine-related disability of migraineurs. Results: Of the 58 participants, 31 were eligible to be included. The validity of the Thai-version questionnaire between the MIDAS total score and the mean headache severity (question B), the mean pain duration per attack, and the mean pain numerical rating scale (NRS) score were moderately correlated with a Spearman correlation coefficient range 0.42-0.58. The test-retest reliability of MIDAS grade had a weighted kappa of 0.66, and for individual questions of the MIDAS total score, questions A and B assessed by intraclass correlation coefficients ranged 0.89-0.98. The internal consistency had a Cronbach alpha of 0.98. The mean pain NRS score in the past 3 months was an independent predictive factor for migraine-related disability. Conclusion: The Thai-version MIDAS Questionnaire has moderate concurrent validity, acceptable internal consistency, and excellent test-retest reliability. It would be helpful to assess clinical outcomes. Future study with a standardized translation process for the Thai-version questionnaire and a larger sample size is warranted to confirm internal consistency and determine all probable predictive factors for migraine-related disability.