Abstract
The objective of this study was to examine whether depressive symptoms and social vulnerability factors-including living alone, Basic Livelihood Security Program recipient status, and lack of private health insurance-are associated with non-adherence to antihypertensive medication among Korean adults. This cross-sectional analysis used nationally representative data from the Korea National Health and Nutrition Examination Survey (KNHANES), specifically the 2014 (6th cycle-2nd year), 2016 (7th-1st year), 2018 (7th-3rd year), and 2020 (8th-2nd year) cycles, the only survey years that included both depressive symptoms data and antihypertensive medication use information. Non-adherence was defined as taking prescribed medication on fewer than 20 days during the previous month. Depressive symptoms were assessed using the Patient Health Questionnaire-9. Complex survey logistic regression models were used to evaluate associations between psychosocial factors and non-adherence. Two analytic models were applied: individual models for each psychosocial variable and a combined model adjusting for age, sex, obesity, smoking, alcohol use, physical activity, diabetes, and dyslipidemia. Subgroup analyses were performed by age (<70 and ≥70 years). Among adults aged 40 years or older taking antihypertensive medication, approximately one in ten reported non-adherence. In the fully adjusted model, none of the psychosocial factors-including depressive symptoms, living alone, Basic Livelihood Security Program recipient status, or lack of private insurance-were significantly associated with non-adherence in the overall population. However, depressive symptoms were significantly associated with non-adherence among adults aged 70 years or older, whereas no significant associations were observed in younger adults or sex-specific subgroups. These findings suggest that depressive symptoms do not uniformly influence antihypertensive medication adherence across the adult population but may play a more important role in older adults. Incorporating routine screening for depressive symptoms into hypertension management for older individuals may support more effective adherence and improved clinical outcomes.