Development and Evaluation of a Medication Adherence Measure for Inhaler Use Among Patients with Asthma.

Background: Limited scales exist for assessing adherence among inhaler users, and information on validity and diagnostic characteristics is lacking. This study aimed to develop a Medication Adherence Measure for Inhaler Users (MAM-I) and assess its reliability, validity, and cutoff score for determining nonadherence in patients with asthma. Methods: A cross-sectional study, which included 145 patients with asthma, was conducted. The participants completed the Mini Asthma Quality of Life Questionnaire (MiniAQLQ), the Marlowe-Crowne Social Desirability Scale (MCSDS), and the 7-item MAM-I. The reliability of the scale was determined using Cronbach's alpha, and its validity was examined in terms of criterion, concurrent, predictive, and construct validity. The diagnostic characteristics and cutoff point for nonadherence to inhaler use were also evaluated using the receiver operating characteristic (ROC) curve, with asthma control at month 6 as the gold standard. Results: The MAM-I showed a Cronbach's alpha value of 0.784 at baseline and 0.749 at month 6. Significant correlations were found between the MAM-I scores and adherence scores (P < 0.001), asthma control levels (P < 0.001), and quality of life scores (P < 0.001). The cutoff point for nonadherence was < 15, with a sensitivity of 78.95%, specificity of 98.13%, positive predictive value (PPV) of 93.75%, negative predictive value (NPV) of 92.92%, and accuracy of 93.10%. Conclusion: The MAM-I shows satisfactory reliability and validity, with good diagnostic properties and a cutoff score of less than 15. This scale can be a helpful tool for identifying inhaler nonadherence in asthma management.