Psychometric evaluation of a K orean version of the 8‐item Medication Adherence Scale in rural older adults with hypertension

Objective To examine the psychometric properties of a structured self‐reported 8‐item K orean‐version Morisky Medication Adherence Scale ( MMAS ‐ K ) among rural older adults with hypertension. Design Cross‐sectional descriptive survey. Setting A rural community comprising three primary health care posts in G angwon Province, S outh K orea. Participants Ninety‐two older adults with hypertension who received treatment at primary health care posts. Main outcome measures Participants completed an 8‐item MMAS ‐ K questionnaire, and the community health practitioners manually measured blood pressure. Factor analysis and correlation coefficient for validity and the K uder– R ichardson alpha coefficient for reliability of the MMAS ‐ K were used, while the association between medication adherence and blood pressure control was determined using F isher's exact test. Results Internal consistency reliability was acceptable with a coefficient alpha of 0.71. The factor analysis of construct validity identified two dimensions of the 8‐item MMAS ‐ K , explaining 52.22% of the total variance. There was a high correlation between the 8‐item MMAS ‐ K and the original 4‐item MMAS ( r   =  0.874), indicating that these scales measure theoretically related constructs for convergent validity. There was a significant association between the 8‐item MMAS ‐ K score and blood pressure control ( P   <  0.05), indicating that, for the known‐groups validity, the controlled blood pressure group was more likely to have higher rate of medication adherence than the poor‐control group. Conclusions The findings indicate a positive association between medication adherence and blood pressure control. The 8‐item MMAS ‐ K possesses adequate validity and reliability among rural older adults with hypertension.