Reliability analysis of MyMAAT-12 scale.

Background
Medication adherence is essential for managing chronic kidney disease (CKD) and preventing its progression. In Malaysia, adherence is commonly assessed using the 12-item Likert scale Malaysia Medication Adherence Assessment Tool (MyMAAT-12), but it has not been validated for CKD patients. Thus, this study aimed to validate and explore its potential for item reduction among non-dialysis CKD patients.
Methods and findings
A cross-sectional, multi-center study was conducted across eight health facilities in Pahang state from December 2023 to August 2024. Non-dialysis CKD patients aged 18 years and above, with or without diabetes, attending outpatient clinics, were given the 12-item self-administered MyMAAT-12 and items from the Beliefs about Medicines Questionnaire (BMQ). Patient demographics, HbA1c levels, and serum phosphate changes within three months preceding MyMAAT-12 completion were collected.
The dimensionality of the scale was explored through exploratory factor analysis (EFA), and its reliability and criterion validity were evaluated to ensure robust measurement properties. A simulation test was conducted to explore the feasibility of reducing MyMAAT-12 to a shorter version.
A total of 246 respondents participated, predominantly female (54.5%) and Malay (91.5%), with a mean age of 59.5 ± 12.5 years and an average CKD duration of 5.0 ± 5.4 years. The average medication adherence score was poor to moderate (<54/60). MyMAAT-12 demonstrated excellent internal consistency (Cronbach’s alpha = 0.90) and significant association with BMQ categories (χ²(2) = 16.8, p < 0.01). EFA identified a two-factor structure. MyMAAT-12 adherence categorization was significantly associated with HbA1c% (<8% vs. ≥ 8%) (χ2(2) = 4.7, p = 0.03) and phosphate level changes (χ2(2) = 5.48, p = 0.02). Results indicated that reducing MyMAAT-12 to a 7-item scale was feasible, while maintaining strong psychometric properties (Cronbach’s alpha = 0.87) and a significant association with HbA1c% (ρ = −0.22, p = 0.01).
Conclusion
MyMAAT-12 demonstrated strong reliability and validity, making it a valuable tool for clinicians to accurately assess medication adherence in non-dialysis CKD patients. The shortened MyMAAT-7 offers a streamlined alternative with strong psychometric properties, enhancing clinical practicality.