Impact of Medication Adherence and Quality of Life in Adults With a Single Chronic Condition or Multimorbidity: A Narrative Review

Introduction. Medication adherence plays a critical role in the clinical management of chronic conditions and may significantly influence patients' quality of life (QoL). Understanding this relationship is particularly important in populations with multimorbidity. Focusing on the problem of chronic conditions and multimorbidity in young adults is crucial because they represent the active part of society and chronicity is now public health concern due to the high number of incidence and mortality among this group population. Methods. An extensive literature search was conducted in the PubMed/MEDLINE, Scopus, and Web of Science databases for the period 2014–2024. The search strategy used both Medical Subject Headings (MeSH) and keywords related to medication adherence, quality of life, chronic conditions, and adult populations. Original, full-text articles published in English between 2014 and 2024 were included if they involved adults aged 18–65 with one or more chronic conditions (e.g., diabetes, hypertension, COPD), living in community settings. Eligible studies employed RCTs, cohort, cross-sectional, case-control, qualitative, or mixed-methods designs and reported on both medication adherence and quality of life. Studies were excluded if they focused on psychiatric, oncologic, surgical, transplant, or dialysis populations, hospital-based settings, or lacked relevant adherence and quality of life outcomes. This review is in PROSPERO with code CRD42025641905 Results. Eleven studies were included, cross-sectional, randomized control trial, mixed methods, semi directive interview. Most studies demonstrated a positive association between medication adherence and quality of life, with higher adherence linked to better physical, psychological, and social well-being. Pharmacist-led interventions and digital tools emerged as effective strategies for improving adherence. However, heterogeneity in measurement tools and study populations limited comparability. Discussion. Medication adherence is a key modifiable factor influencing quality of life among individuals with chronic conditions and multimorbidity. Multidimensional adherence-enhancing strategies—including education, patient empowerment, and system-level changes—are essential. Future research should adopt robust methodologies and standardized outcome measures to better inform clinical practice and policy.