Psychometric Properties of the Persian Version of the Morisky Medication Adherence Scale-8

Background: Hypertension is a global public health crisis. Poorly controlled high blood pressure is one of the most important factors contributed to this crisis. Lack of medication adherence is often considered as the main reason for insufficient control of high blood pressure. Difficulty in measuring medication adherence is another problem in this field. To reduce this difficulty several medication adherence scales were developed. This study was performed to test reliability and validity of Morisky Medication Adherence Scale-8.

Materials and Methods: A cross-sectional study was conducted to validate the Persian version of MMAS-8. The Persian version of MMAS-8 was generated by using a modified forward/backward translation procedure. Two hundred and fifty hypertensive patients were participated in the study. Construct and known-groups validity, Cronbach’s alpha and test-retest reliability were used to assess psychometric properties of Persian scale.

Results: Data analysis showed that the scale did not have an acceptable internal consistency (Cronbach’s Alpha= 0.40) but had excellent stability (p= 0.89). The confirmatory factor analysis poorly fitted with one-dimensional model. Participants with controlled blood pressure had significantly higher MMAS-8 scores than uncontrolled blood pressure group.

Conclusion: Totally some of the psychometric properties of the Persian version of the MMAS-8 did not meet the requirements of the standard level so it is not recommended to use in general. More studies are needed to establish a more appropriate scale in order to be used in the mentioned population.