Key drivers of medication adherence in patients with comorbid diabetes mellitus and depression: a scoping review

Background: In patients with diabetes mellitus, depression is one of the most common mental health conditions, significantly contributing to poor health outcomes. Medication adherence plays a critical role in improving their health outcomes. While factors influencing medication adherence have been studied, a comprehensive review applying the World Health Organization Multidimensional Adherence Model (WHO-MAM) framework in patients with comorbid diabetes and depression has not been conducted. Aim: To conduct a scoping review on factors affecting medication adherence using the WHO-MAM and interventions aimed at improving adherence among patients with comorbid diabetes and depression. Design: A systematic literature search was conducted in the following databases: Scopus, MEDLINE, and Web of Science. One search engine, Google Scholar, was included. The Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines were followed for this review. A total of 2234 unique studies were identified. Only peer reviewed research focusing on patients with comorbid diabetes and depression was considered. Additionally, studies had to be published in English and provide explicit assessments of medication adherence. Based on these criteria, a total of 19 studies were selected for analysis. Results: Principal factors and interventions affecting adherence comprised polypharmacy (p < 0.001), glycaemic control (HbA1c) (p < 0.001), sertraline administration (p < 0.0001), integrated care models (p = 0.04), and cognitive-behavioural therapy interventions (p < 0.02). An adherence rate of 20.7%–95.8% was observed using both self-reported and objective measures. Conclusion: Patients taking sertraline, integrated care approaches, and customised interventions show potential in enhancing adherence. Future research should investigate racial disparities and evaluate the long-term impacts of interventions aimed at improving patient-centred care.