Validation of diabetes medication adherence scale in the Lebanese population

Aim: To validate the Diabetes Medication Adherence Scale (DMAS-7), determine its concordance with another validated scales and to assess factors affecting medication adherence. Methods: A cross-sectional study was conducted on a sample of Lebanese patients with diabetes using a questionnaire. The level of adherence was measured using the DMAS-7 and the Lebanese Medication Adherence Scale (LMAS-14). Bivariate and multivariate analyses were conducted, and the scale was validated in terms of reliability, predictive ability, and construct validity using SPSS version 19. Results: Out of 300 eligible patients, the rate of adherence was 33.7%. Measures of validity showed good reliability (Cronbach alpha = 0.627), and good construct validity with LMAS-14 (Spearman's rho = 0.846; Cohen's kappa = 0.711). DMAS-7 was found to be both correlated with LMAS-14 (ICC average measure = 0.675; p-value <0.001) in addition to possessing a better predictive value. Thus, DMAS-7 showed to have good concordance and increased validity compared to LMAS-14. Having an optimal glycated hemoglobin (HbA1C) (OR = 0.779; p = 0.001) and performing regular physical activity (OR 2.328; p = 0.002) increased medication adherence. Conclusion: The DMAS-7 showed to be reliable and valid instrument superior to LMAS-14 in predicting adherence levels to oral anti-diabetic medications, and thus can be used to achieve better glycemic outcomes.