Development and validation of CF-Medication Beliefs Questionnaire: A mixed-methods approach

Background Beliefs about medication have been associated with adherence in other diseases but there are no existing disease-specific medication beliefs questionnaires for CF. This mixed-methods validated the Cystic Fibrosis Medication Belief Questionnaire (CF-MBQ), based on social cognitive theory. Methods Based on previous research, items were developed for five domains: motivation, self-efficacy, perceived importance, and decisional balance to take or miss medications. Cognitive interviews were conducted with 15 adult patients with CF to refine item development. 128 patients with CF completed an online survey and objective medication adherence was measured using pharmacy refill data. Results The five subscales demonstrated strong psychometric properties, with adequate-to-good internal consistency scores. More importantly, each domain demonstrated construct validity with adherence. Conclusions These theoretically-derived measures may be important for clinical purposes to provide guidance on appropriate interventions to improve adherence and for research to provide enhanced understanding on patient determinants of medication adherence.