Analysis of Determinants of Medication Adherence among Older Adults with Hypertension and Diabetes using the WHO Multidimensional Model: A Study Based on Korean Medical Panel Data (KHP)

Purpose: This study aimed to comprehensively analyze the multidimensional determinants of medication adherence among older adults in Korea using the World Health Organization (WHO) multidimensional model, which incorporates socioeconomic, health care system, condition-related, treatment-related, and patient-related dimensions, based on data from the Korea Medical Panel (KHP).Methods: A total of 2,888 community-dwelling older adults aged 65 years and older were analyzed using the 2021 KHP dataset. Medication adherence was classified into adherence and non-adherence groups. Block-entry logistic regression analysis was conducted according to the WHO multidimensional model, and model fit was evaluated using the Hosmer-Lemeshow test and Nagelkerke R<sup>2</sup>.Results: Among the participants, 69.4% were classified as adherent and 30.6% as non-adherent. Of the five dimensions, patient-related factors contributed most strongly to the final model (Nagelkerke R<sup>2</sup>=.045), including perceived stress, health literacy, and health-related quality of life. Condition-related factors, such as the number of chronic diseases, bedridden status, and need for care, also showed significant associations with medication adherence. Treatment-related factors, including medication side effects, and health system factors, such as unmet medical needs, were identified as additional predictors. Socioeconomic factors, including living alone and male sex, contributed modestly. Overall, the block-entry model demonstrated incremental improvements in explanatory power as each dimension was sequentially added.Conclusion: Medication adherence among older adults is influenced by multidimensional determinants across the five WHO domains. Patient-related and condition-related factors exerted the strongest effects, followed by treatment-related, health care system, and socioeconomic factors. These findings underscore the need for comprehensive, multidimensional nursing interventions tailored to older adults to effectively improve medication adherence.