Validity evidence of adapted hausa version of 8-item Morisky medication adherence scale in patients with hypertension in North-Western Nigeria

Abstract

Adherence to antihypertensive medication is the cornerstone for achieving hypertension control. Morisky Medication Adherence Scale (MMAS-8) is one of the most widely used self reported medication adherence measures. The aim of this study was to examine the evidence of the validity of adapted Hausa MMAS-8 in assessing adherence among hypertensive patients in North-western Nigeria. In a longitudinal interventional study of individuals with hypertension, self-reported adherence to the antihypertensive drug treatment was measured using the Morisky Medication Adherence Scale-8. The internal consistency of the Morisky Medication Adherence Scale-8 with Cronbach’s alpha, and factorial validity was assessed by identifying the underlying components using principal component analyses (PCA). A total of 130 individuals completed the study. Cronbach’s alpha was 0.79. Two components were identified. One component comprised six items: stopping medication when hypertension is under control, stopping when feeling hassled about sticking to the prescription. The second component comprised two other items that were all related to forgetfulness. A significant relationship between MMAS and diastolic blood pressure control (t = 2.2; p = .030), (χ² = 6.6; p = .036) was found. The MMAS sensitivity and specificity, with positive and negative predictive values were 36%, 77%, 64%, and 52% respectively. The results suggest that the adapted Hausa Morisky Medication Adherence Scale-8 is a two-dimensional scale assessing intentional (first component) and unintentional (second component) non-adherence to the antihypertensive drug treatment. The findings of this validation study indicate that the Hausa version of the MMAS is a reliable and valid measure of medication adherence among hypertensive patients in North-western Nigeria.

Keywords: Adherence; Hypertension; MMAS-8; Validation.