Charting the path to better diabetes outcomes: Revealing psychosocial influences on medication adherence through the information-motivation-behavioral skills model among adults with type 2 diabetes

Background Psychosocial factors like beliefs, distress, and behavioral skills affect medication adherence. The Information-Motivation-Behavioral Skills (IMB) model addresses these through integrated knowledge, motivation, and skills to support adherence. Objective This study applied the IMB model to identify salient factors associated with medication adherence and glycemic control among adults with type 2 diabetes (T2D), aiming to clarify mechanisms underlying non-adherence. Methods A cross-sectional survey was conducted from June 2023 to May 2024 at five community pharmacies in Taiwan using convenience sampling. Eligible participants were adults diagnosed with T2D, currently prescribed at least one oral diabetes medication, and able to read Traditional Chinese. Data were collected via a structured questionnaire covering demographics, clinical characteristics, and four IMB-based constructs. Specifically, eHealth literacy represented the information component; medication-related beliefs (i.e., perceived concerns and necessity of medications) reflected the motivation construct; and self-efficacy captured behavioral skills. Medication adherence was assessed in two domains: medication-taking and medication refill behaviors. Path analysis was used to examine relationships among psychosocial variables, adherence behaviors, and glycemic control. Results A total of 273 participants completed the questionnaire. Higher self-reported medication-taking behavior was significantly associated with better glycemic control (β = 0.198, p < 0.001). This behavior was positively influenced by stronger eHealth literacy (β = 0.177, p = 0.002), fewer medication-related concerns (β = 0.307, p < 0.001), and greater perceived necessity of medications (β = 0.124, p = 0.027), with self-efficacy serving as a key mediator (β = 0.257, p < 0.001). Refill adherence was also linked to improved A1C levels (β = 0.120, p = 0.028), though no psychosocial predictors were identified for this domain. Conclusions The IMB model offers a useful framework for understanding adherence behaviors in T2D. Self-efficacy emerged as a central influence, mediating the effects of eHealth literacy and beliefs about medicines.