title: Reliability, validity, and clinical utility of the Migraine-ACT questionnaire.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  To further analyze the Migraine-ACT study database, providing additional information on the reliability, validity, and potential clinical utility of the questionnaire.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  These data confirm the excellent reliability and validity of the Migraine-ACT questionnaire and provide further evidence for its utility in clinical practice.
authors.affiliation: Institute of Naval Medicine, Alverstoke, Hampshire, UK.
authors.forename: Shaun G
authors.initials: SG
authors.lastname: Kilminster
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Dowson
authors.forename: Stewart J
authors.initials: SJ
authors.lastname: Tepper
authors.forename: Vicente
authors.initials: V
authors.lastname: Baos
authors.forename: Francis
authors.initials: F
authors.lastname: Baudet
authors.forename: Domenico
authors.initials: D
authors.lastname: D'Amico
mesh_terms: D000208:Acute Disease; D006801:Humans; D008487:Medical History Taking; D008881:Migraine Disorders / Q000188:drug therapy*; D017063:Outcome Assessment, Health Care / Q000379:methods*; D020127:Recovery of Function; D012720:Severity of Illness Index; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires / Q000592:standards*