The eight-item Morisky Medication Adherence Scale MMAS: Translation and validation of the Malaysian version

Abstract

Aims To translate and examine the psychometric properties of the Malaysian version of the Morisky Medication Adherence Scale (MMAS) among patients with type 2 diabetes. Methods A standard “forward–backward” procedure was used to translate MMAS into Malay language. It was later validated on a convenience sample of 223 type 2 diabetes outpatients between May and September 2009. Reliability was tested for internal consistency. Validity was confirmed using convergent and known group validity. Results Employing the recommended scoring method, the mean ± SD of MMAS scores was 6.13 ± 1.72. Moderate internal consistency was found (Cronbach's α = 0.675), the test–retest reliability value was 0.816 ( p < 0.001). A positive correlation between the eight- and four-item MMAS was found ( r = 0.792; p < 0.01). A significant relationship between MMAS categories and HbA1c categories ( χ 2 = 20.261; p ≥ 0.001) was found. The MMAS sensitivity and specificity, with positive and negative predictive values were 77.61%, 45.37%, 46.84% and 76.56%, respectively. Conclusions The findings of this validation study indicate that the Malaysian version of the MMAS is a reliable and valid measure of medication adherence which can now be used.