Factors affecting medication adherence in elderly people

Background: Little is known about the functional health literacy (FHL) associated with medication adherence in elderly patients. The aim of this study was to examine the FHL among older adults and identify influencing factors that can predict medication adherence. Methods: This was a cross-sectional survey. Participants (n=160) aged 65 years and older were selected from outpatient clinics of 3 tertiary care hospitals, 6 community pharmacies, and 2 senior centers between November 1 and 30, 2014. The participants' FHL was measured using the Korean Functional Health Literacy Test, which consists of 15 items including 8 numeracy and 7 reading comprehension items. Medication adherence was measured by the Adherence to Refills and Medication Scale. Descriptive statistics, chi-square or Fisher's exact test, and multiple regression analyses were used to analyze the data. Results: The mean score of the total FHL was 7.72 +/- 3.51 (range 0-15). The percentage of the total number of correct answers for the reading comprehension subtest and numeracy subtest were 48.1% and 54.4%, respectively. Among 160 participants, 52.5% showed low adherence to medication. The factors affecting medication adherence included the patient's degree of satisfaction with the service (beta=-0.215, P=0.022), sufficient explanation of medication counseling (beta=-0.335, P=0.000), education level (beta=-0.153, P=0.045), health-related problems (beta=-0.239, P=0.004), and dosing frequency (beta=0.189, P=0.018). Conclusion: In this study, we found medication adherence of elderly patients was associated with education level, health-related problems, dosing frequency, satisfaction with patient counseling, and explanation of medication, but no association was found with FHL. Pharmacists should consider elderly patients' individual characteristics such as educational background and specific patient-related health problems, provide sufficient information and explanation of medication, and ensure patient satisfaction with the counseling.