Scoping Review of Studies Evaluating Frailty and Its Association with Medication Harm

Frailty is associated with an increased risk of death and morbid events. Frail individuals are known to have multiple comorbidities which are often associated with polypharmacy. Whilst a relationship between polypharmacy and frailty has been demonstrated, it is not clear if there is an independent relationship between frailty and medication harm.

This scoping review aimed to identify and critically appraise studies evaluating medication harm in patients with frailty.

PubMed, EMBASE, CINAHL and Cochrane databases were searched from inception until 1 February 2021 using key search terms that are synonymous with frailty (such as frail and frail elderly) and medication harm (such as adverse drug events and adverse drug reactions). To be included, studies must have identified medication harm as a primary or secondary outcome measure, and used a frailty assessment tool to determine frailty, or clearly defined how frailty was assessed. Data were narratively synthesised and presented in tables. The checklist from the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies from the National Heart, Lung, and Blood Institute was used to assess the quality and risk of bias of studies that met the inclusion criteria.

Of 2685 retrieved abstracts, 24 underwent full-text review and nine studies met the inclusion criteria. Three studies were retrospective cohort studies, and six were prospective observational studies. Six studies comprised two distinct groups of frail and non-frail individuals, and the remaining three studies evaluated medication harm in an entirely frail population. Seven studies used validated frailty tools such as the Clinical Frailty Scale, Fried Frailty Index, and Fried Frailty Phenotype. Two studies measured frailty using self-defined criteria. Overall, frail individuals were at risk of medication harm with rates ranging between 18.7 and 77% across the nine studies. However, whether frailty is an independent predictor of medication harm remains uncertain, as this was only evaluated in one study. The risk of bias assessment identified limitations in methods and reporting with all nine studies.

This scoping review identified nine studies evaluating medication harm in frail patients. However, all were limited by the methodological quality and inadequate reporting of study factors. There are few high-quality studies that described a relationship between medication harm and frailty. More robust studies are required that examine the independent relationship between frailty and medication harm, after adjusting for all possible confounders and in particular polypharmacy.