OBJECTIVES: Medication non-adherence in the older aged population is multi-faceted, related to a combination of drug-related and patient-physician factors. Most of the literature focuses on the association between adherence within particular medication classes and disease-specific surrogate outcomes. This systematic review aims to determine the association between medication adherence and health outcomes such as healthcare utilisation and quality of life in ageing adults (≥50 years).

METHODS: We searched PubMed, EMBASE, PsycINFO, CINAHL, WebOfScience, Scopus and the Cochrane Library for prospective and retrospective studies (cohort, case-control and cross-sectional) that report the association between medication adherence and health outcomes. Studies that measured implementation adherence, as per the ABC taxonomy, using pharmacy data, electronic monitoring devices such as MEMs^©, pill count, or validated self-report questionnaires were included. Healthcare utilisation outcomes included hospitalisation, ED visits, outpatient visits and GP visits (generic and disease-specific). Disease-specific endpoints that require intervention or impact on quality of life were included; falls, MI, stroke, fracture etc. General or health related quality of life was measured using validated instruments. See PROSPERO (reference: CRD42017077264).

RESULTS: In total, 5579 abstracts were screened. A second reviewer screened a random 50% of abstracts. 28 full-text articles were included from abstract screening, and two additional from reference screening (n=30). Most of the studies included were in elderly people (≥ 65 years), measured adherence using pharmacy data and focused on a wide range of conditions, the most common being cardiovascular diseases. Data extraction is ongoing, but initial crude results indicate that there is an overall significant association between medication non-adherence and increased hospitalisations, falls, fractures (for osteoporosis medications) and death. Studies examining the association between adherence and quality of life are generally of poor quality and indicate mixed results.

CONCLUSIONS: Medication non-adherence in older people appears to be associated with increased healthcare utilisation and an increased risk of death.