Medication Adherence Assessed By MMAS-8 Among Outpatients With Chronic Cardiometabolic Diseases In Northern Vietnam: A Multicenter Cross-Sectional Study

Background: Medication adherence is essential for long-term control of hypertension and type 2 diabetes mellitus, yet data from multicenter outpatient populations in Vietnam remain limited. This study described medication adherence using the 8-item Morisky Medication Adherence Scale (MMAS-8) and identified factors associated with adequate adherence among outpatients with chronic cardiometabolic diseases. Methods: This multicenter cross-sectional study used harmonized outpatient datasets from Saint Paul Hospital, Phu Tho Provincial General Hospital, and 108 Military Central Hospital in northern Vietnam. A total of 819 adults with hypertension, type 2 diabetes mellitus, or both were included. MMAS-8 scores were recalculated from item-level responses and categorized as high adherence (score 8), medium adherence (score 6 to <8), and low adherence (score <6). Adequate adherence was defined as an MMAS-8 score ≥6. Bivariable analyses and multivariable logistic regression were used to identify factors associated with adequate adherence. Results: The mean age was 70.8 ± 8.5 years, and 66.4% were male. Among 819 patients with complete MMAS-8 data, adequate adherence was observed in 598 patients (73.0%), including high adherence in 226 (27.6%) and medium adherence in 372 (45.4%); 221 patients (27.0%) had low adherence. Adequate adherence was highest at 108 Military Central Hospital (82.7%) and lowest at Phu Tho Provincial General Hospital (62.9%). After adjustment, dietary adherence (adjusted OR 3.75, 95% CI 2.60-5.42) and exercise adherence (adjusted OR 4.43, 95% CI 2.87-6.82) remained strongly associated with adequate medication adherence. Patients at Phu Tho Provincial General Hospital also had lower adjusted odds of adequate adherence than those at Saint Paul Hospital (adjusted OR 0.61, 95% CI 0.39-0.97). Item-level analysis showed that Q1 was the most frequent non-adherent response overall, reported by 457/819 patients (55.8%). Conclusions: Approximately three-quarters of outpatients achieved adequate medication adherence, but only about one-quarter achieved high adherence. The strong associations between medication adherence and lifestyle adherence suggest that medication-taking behavior is part of a broader self-management pattern. Integrated interventions combining medication counseling, lifestyle support, reminder strategies, and site-specific quality improvement are warranted.