Abstract

Background: Adherence to medication is an essential part of achieving health outcomes in the elderly. However, there is a paucity of data regarding medication adherence and associated factors in Thailand, especially in tertiary settings where patients have more complicated medication regimens.

Methods: This was a cross-sectional study conducted from May 2019 to May 2020.We examined older patients at the outpatient clinic of an internal medicine department at a tertiary care hospital in Thailand. Eligible patients included age ≥ 60 years, had at least one chronic disease that requires long-term medication, and had to follow-up regularly for at least three months before participating in this study. Exclusion criteria were patients with mental, visual, aural, or severe limb impairment that interfered with communication or self-management of medication. Demographic characteristics were collected, and the 8-item Morisky Medication Adherence Scale (MMAS-8) was used to measure medication adherence.

Results: A total of 250 participants were included, of whom 24.2%, 39.2%, and 36.4% practiced good, moderate, and poor medication adherence, respectively. Multivariate regression analysis showed poor medication adherence was associated with adverse drug reactions (ADR, adjusted odds ratio [AOR] 4.8), concurrent use of over-the-counter (OTC) drugs (AOR 2.02), and high Thai Geriatric Depression Scale (TGDS) scores (AOR 1.44).

Conclusion: Self-reported nonadherence to medication is prevalent in geriatric outpatients with chronic diseases. Factors associated with poor medication adherence were identified. Targeted intervention is recommended to improve compliance included thoroughly taking history of ADR, review all current prescriptions and OTC drugs, and depression screening.