Reliability, validity, and clinical utility of the Migraine-ACT questionnaire.Headache. 2006 Apr; 46(4):553-62.H
The 4-item Migraine-ACT questionnaire is an assessment tool for use by primary care physicians to identify patients who require a change in their current acute migraine treatment. It has been shown to be easy to use, and to be reliable and accurate in its assessments.
To further analyze the Migraine-ACT study database, providing additional information on the reliability, validity, and potential clinical utility of the questionnaire.
Reliability was assessed by recording the distribution of Migraine-ACT scores recorded at baseline and 1 week later (test-retest reliability). Analyses of consistency of Migraine-ACT scores were conducted on the total sample of patients and for the separate centers, using Pearson and Spearman correlations. Validity was assessed by comparing the t-discrimination values for clinically relevant questions within domains of the original 27-item questionnaire. Reliability and validity were also assessed by constructing an "alternative" (Form B) Migraine-ACT questionnaire, derived from an analysis of the second-best items in each domain in the original study data. Clinical utility was assessed using Pearson pairwise correlations to compare Migraine-ACT scores with clinically defined criteria as analyzed by the SF-36 Quality of Life questionnaire, the Migraine Disability Assessment (MIDAS) questionnaire, and the Migraine Therapy Assessment (MTAQ) questionnaire.
The distribution of Migraine-ACT scores between the 2 completions of the questionnaire was consistent for the total sample (test-retest reliability, r= .81) and between the individual countries (r= .61 to .92). In this study, the validity (assessed as t-discrimination) of the Migraine-ACT "impact" and "global assessment of relief" questions were markedly higher than those of other endpoints used in migraine clinical studies. The Form B Migraine-ACT questionnaire was almost as reliable and accurate as the original Form A questionnaire. The distribution of Migraine-ACT scores was: 0 = 12.6%, 1 = 13.7%, 2 = 14.7%, 3 = 20.5%, and 4 = 38.4%. The change in Migraine-ACT score correlated with, and had a linear relationship with changes in SF-36, MIDAS, and MTAQ scores, and indicated that a Migraine-ACT score of <or=2 corresponded with a need to consider changing the patient's acute medication. About 40% of the migraine patients in the study scored <or=2 and may have had significant unmet treatment needs.
These data confirm the excellent reliability and validity of the Migraine-ACT questionnaire and provide further evidence for its utility in clinical practice.