Assessment of Factors Influencing Medication Adherence in Patients with Type 2 Diabetes Mellitus in Bengaluru: A Structural Equation Modelling Study

Aims This study examined psychosocial, clinical, and healthcare system-related factors associated with medication adherence among patients with Type 2 Diabetes Mellitus (T2DM) in Bengaluru, India, using Structural Equation Modelling (SEM). Methods A cross-sectional study was conducted at a tertiary care hospital in Bengaluru between March and May 2025, enrolling 600 adult T2DM patients through purposive sampling. Validated instruments measured medication adherence (MMAS-8), self-efficacy, perceived social support, neuroticism, health literacy, and health-related quality of life (HRQoL). SEM was applied to assess direct and indirect pathways influencing adherence. Results Self-efficacy (β = 0.425, p < 0.05) was the strongest direct predictor of adherence. While perceived social support did not directly influence adherence (β = 0.027, p = 0.494), it showed a significant positive association with self-efficacy (β = 0.473, p < 0.05), exerting an indirect effect on adherence via enhanced confidence in diabetes self-management. HRQoL had a modest, significant positive effect (β = 0.171, p < 0.05). Health system factors (β = -0.017, p = 0.785) and medication complexity (β = -0.049, p = 0.335) did not show significant direct associations. The final model accounted for 28.4% of the variance in adherence (R² = 0.284), highlighting the mediating role of self-efficacy. Conclusions The findings underscore the pivotal role of self-efficacy and social support in promoting adherence among Indian patients with type 2 diabetes mellitus (T2DM). Interventions that strengthen psychological resources and social networks could enhance adherence and clinical outcomes.