Validity and Reliability of the Medication Adherence Scale in Thais (MAST): Testing in Diabetes Patients
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Abstract
Objectives: To test validity and reliability of the Medication Adherence Scale in Thais (MAST) among patients with diabetes and determine the cut-off point indicating appropriate medication adherence level. Method: Participants were 251 patients with type 2 diabetes visiting Queen Savang Vadhana Memorial Hospital in Sriracha, Chonburi. All participants completed questionnaires consisting of the MAST, the Diabetes-39, the Thai Health Literacy Assessment using Word List and the Marlowe-Crowne Social Desirability Scale. Their medication adherence was also measured by pill counting. In addition, fasting plasma glucose (FPG) and glycated hemoglobin (HbA1C) 6 months after enrollment into the study were measured. Cut-off point was determined using receiver operating characteristic curve (ROC curve). Results: On criterion-related validity test, the MAST scores were associated with pill count (P < 0.001). Test of predictive validity showed scores from the MAST were associated with FPG and HbA1C levels measured 6 months later (P < 0.001). Regarding construct validity, scores from the MAST was associated with quality of life and health literacy (P < 0.001). The MAST could discriminate patients with good (HbA1C < 7%) or poor glycemic control (HbA1C ≥ 7%) (P < 0.001). The MAST showed no significant correlation with the MCSD. Two evaluation of the MAST’s reliability revealed Cronbach’s Alphas at 0.828 and 0.925. Test-retest reliability was satisfactory (r = 0.840). The cut-off point of the MAST was 34 with sensitivity of 85.8%, specificity of 89.7%, positive predictive value of 90.6% and negative predictive value of 84.7%. Conclusion: The MAST had a good validity and reliability. It also had a high level of sensitivity, specificity and predictive value. Accordingly, the MAST is an appropriate instrument for evaluating medication adherence among patients with diabetes.
Article Details
ผลการวิจัยและความคิดเห็นที่ปรากฏในบทความถือเป็นความคิดเห็นและอยู่ในความรับผิดชอบของผู้นิพนธ์ มิใช่ความเห็นหรือความรับผิดชอบของกองบรรณาธิการ หรือคณะเภสัชศาสตร์ มหาวิทยาลัยสงขลานครินทร์ ทั้งนี้ไม่รวมความผิดพลาดอันเกิดจากการพิมพ์ บทความที่ได้รับการเผยแพร่โดยวารสารเภสัชกรรมไทยถือเป็นสิทธิ์ของวารสารฯ
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