Effectiveness of Culture-Based Group Activity Therapy on Medication Adherence and Clinical Outcomes Among Patients with Type 2 Diabetes Mellitus: A Quasi-Experimental Study

Background: Culturally adapted interventions may strengthen medication adherence and diabetes self-management. This study evaluated Culture-Based Group Activity Therapy (CB-GAT) incorporating Acehnese cultural values and Islamic principles among patients with type 2 diabetes mellitus. Methods: A nonrandomized quasi-experimental study with a pretest–posttest control group design was conducted at four community health centers in Lhokseumawe, Indonesia, between May and August 2026. The analysis included 100 participants, with 50 in each group. Participants from two centers received eight weekly CB-GAT sessions lasting approximately 90 minutes each, while participants from the other two centers received routine diabetes care. The primary outcome was medication adherence measured using the eight-item Morisky Medication Adherence Scale (MMAS-8). Secondary outcomes included glycated hemoglobin (HbA1c), fasting blood glucose, blood pressure, and body mass index. Outcomes were assessed at baseline and eight weeks and analyzed using repeated-measures analysis of covariance. Results: Mean MMAS-8 scores increased from 5.02 ± 1.14 to 7.41 ± 0.88 in the intervention group and from 5.08 ± 1.09 to 5.46 ± 1.06 in the control group. The reported adjusted estimate for medication adherence favored CB-GAT by 1.98 points (95% CI 1.46–2.49; p < 0.001). Reported adjusted estimates also favored the intervention for HbA1c (−1.02 percentage points; 95% CI −1.34 to −0.71) and fasting blood glucose (−28.44 mg/dL; 95% CI −37.16 to −19.73), both p < 0.001. Favorable changes were also reported for systolic and diastolic blood pressure and body mass index. Conclusions: CB-GAT was associated with short-term improvements in medication adherence and clinical outcomes. However, nonrandomized facility-based allocation and uncertainty regarding adjustment for clustering limit causal interpretation. Randomized studies with adequate facility representation and longer follow-up are needed to confirm these findings.