Factors that Affect Medication Adherence in Elderly Patients with Diabetes Mellitus

BACKGROUND This study was conducted to evaluate the factors affecting medication adherence in geriatric diabetic patients treated at private clinics and tertiary hospitals. We compared the factors affecting medication adherence between these two patient groups. METHODS We included 108 diabetic patients older than 65 years treated at one tertiary hospital and 157 patients older than 65 years treated at two private clinics. We conducted an interview survey based on the Health Belief Model, and used a questionnaire that included the self-efficacy variable. For the medication adherence, Morisky's self-report was used. RESULTS The medication adherence based on Morisky's self-report was significantly higher in tertiary hospital patients (61.1%) compared to private clinic patients (43.2%) (P < 0.01). The results showed that drug storage and self-efficacy were factors affecting adherence to medication in tertiary hospital patients (P < 0.05). The adherence was high in cases of proper drug storage (odds ratio [OR], 5.401) and in cases with high self-efficacy (OR, 13.114). In private clinic patients, financial level (P < 0.05), recognition of the seriousness of diabetes complications (P < 0.05) and self-efficacy (P < 0.01) were associated with medication adherence. The medication adherence was significantly lower in patients whose financial state were moderate than those with lower (OR, 0.410), and medication adherence was significantly higher in patients who had higher perceived severity (OR, 2.936) and in patients with higher self-efficacy (OR, 4.040). CONCLUSION Different strategies should be used to increase medication adherence in geriatric diabetic patients, depending on institutions whether they are treated.