Psychometric properties of the Belief about Medicines Questionnaire (BMQ) in the Maltese language.

BACKGROUND: Investigating beliefs about medicines has been of interest over the past years, with studies aiming to better understand theoretical reasons behind development of such beliefs. OBJECTIVE: This study aimed to produce a culturally and contextually appropriate version of the Beliefs about Medicines Questionnaire (BMQ) in the Maltese language and to assess its psychometric properties. METHODS: Medication beliefs were evaluated using the BMQ which is divided into two sections: BMQ-General (sub-scales: Overuse and Harm, 4 items per sub-scale) and BMQ-Specific (sub-scales: Necessity and Concerns, 5 items per sub-scale). Following translation/back translation, the Maltese version of the BMQ was applied to patients having asthma, diabetes, cardiovascular disease or depression who attended out-patients' clinics at the main state general hospital in Malta between June and September 2013. Cronbach's alpha coefficient, alpha, was used to determine internal consistency of the BMQ and Principal Component Analysis using Varimax rotation with Kaiser normalisation was carried out to analyse component loading of the items on the respective sub-scales. RESULTS: The Maltese version of the BMQ showed acceptable internal consistency for the harm scale (alpha=0.56), the necessity scale (alpha=0.73) and the concerns scale (alpha=0.66), however the overuse scale gave poor internal consistency (alpha=0.48) due to the item on natural remedies which posed some difficulty in the Maltese sample. The final solution for Principal Component Analysis yielded a four-factor structure representing the 4 sub-scales of the BMQ, with results being comparable to previous studies out in different languages. CONCLUSION: The Maltese version of the BMQ was found to have acceptable psychometric properties for the beliefs about medicines in the Maltese population.