PURPOSE: Medication non-adherence represents a socially relevant challenge, particularly when interlinked to multiple chronic diseases and polypharmacy. Non-adherence rates affect treatment efficacy and increase health care costs. The aim of the study was to identify factors influencing medication adherence in the older adults through a systematic review of qualitative studies on patients' experience.
METHODS: Two electronic databases were searched for qualitative studies on medication adherence in chronic diseases (hypertension, heart disease, COPD, asthma) involving people aged 65 + . The systematic review was performed according to the PRISMA statement guidelines, employing theoretical frameworks of the ABC Taxonomy of patient adherence and Three Factor model of determinants of behaviour.
RESULTS: The initial database search identified 1234 records, of which 39 studies were considered eligible. Most of the studies focused on hypertension and were conducted in English-speaking countries. According to the ABC Taxonomy, Persistence and Implementation were the most often considered phases. Considering the Three Factor model, the most often reported themes were Information and Strategies upon being adherent. Stemming from the review findings and the patients' narratives, a new integrated model was proposed. It reports the patient's decisional flowchart describing barriers and facilitators (personal, social and environmental) to adherence.
CONCLUSION: Medication adherence is a complex and multifaceted process. The implementation of theoretical frameworks along with a patient-centred perspective may provide clinicians with useful suggestions for clinical practice, enhancing the patient's ability to adhere.