Methodological features of quantitative studies on medication adherence in older patients with chronic morbidity: A systematic review

Objectives: The growing number of chronic, multimorbid older adults encourages healthcare systems to cope with polypharmacy and non-adherence. However, methodology on how to provide effective interventions to enhance medication adherence is still object of debate. Methods: To describe methodological features of quantitative studies concerning older adults' medication adherence, by means of a PRISMA systematic review (Scopus, PubMed, Medline). A specific focus was devoted to theoretical models and to the ABC Taxonomy model, as stated by the EMERGE guidelines. Results: 55 papers were included. Most of the studies were conducted using randomized control trials (63.6%) and focused on a single disease only (72.7%). Most of the interventions were provided by a single professional figure (70.9%). Medication adherence was mainly evaluated by means of questionnaires (61.8%) and by clinical records (30.9%). Sixteen studies considered a theoretical model in the intervention framework. The Initiation phase (ABC Taxonomy) was the most neglected. Conclusions: Future studies upon medication adherence should account real-life challenges such as multimorbidity, polypharmacy and interdisciplinarity, analyzing adherence as a complex, holistic process. Practice implications: Theoretical models may be useful to enhance the soundness of the results, to ease their comparability, to calibrate tailored strategies and to plan patient-centered interventions. (C) 2020 Published by Elsevier B.V.