PITCH: What adverse outcomes are associated with polypharmacy in later life? A systematic review of reviews.

Problem

Polypharmacy describes the situation where multiple medications are prescribed for an individual. There is no consensus on how polypharmacy should be defined, but it is believed to be common in older adults because they are often living with several medical conditions.

The many potential consequences of polypharmacy include cognitive impairment, adverse drug events, reduced adherence, mortality and increased healthcare utilisation. These have been explored in patients over 65 years of age, but the data is mixed and even less clearly defined in the very old (over 85 years), across a range of healthcare and residential settings.

This is problematic as the very old are the fastest growing section of the population in whom polypharmacy has great potential to generate adverse outcomes, especially when combined with functional decline, multimorbidity and frailty. Polypharmacy is also likely to remain a problem for older people due to disease-specific clinical guidelines and the dearth of information about deprescribing.

Thus, this review aims to summarise the spectrum of polypharmacy-related adverse effects in later life.

Approach

A systematic review of systematic reviews and/or meta-analyses of observational studies in humans will be conducted across eleven relevant databases, from 1990 to the present date. These will include DARE, CDSR, HTA, Epistemonikos, MEDLINE, EMBASE, CINAHL, PsycINFO, PubMed, Scopus and Web of Science. Subject headings and keywords for (i) adverse outcomes, (ii) polypharmacy (iii) older people and (iv) systematic reviews/meta-analyses will be combined to retrieve the relevant literature with sensitivity, assisted by search filters. In addition, relevant journals and reference lists of included reviews will be hand searched, and topic experts contacted. The gray literature will also be searched to maximise retrieval. This review will be documented following the PRISMA 2009 guidance.

Findings

The adverse outcomes from each included review will be tabulated with an accompanying narrative synthesis, ordered by the types of adverse outcomes reported.

It is likely that differences in populations, outcomes, study designs and aggregated risk factor magnitudes will limit a meta-analysis. However, results will be analysed by age (65+, 75+, 85+), degree of polypharmacy, comorbidities and setting if possible. Graphical representation of the effect size for each polypharmacy-related adverse outcome will also be presented if possible.

Consequences

If the spectrum of polypharmacy-related adverse effects were understood in older people, it may be possible to aid holistic patient care and advance our understanding of where future interventions are needed to optimise prescribing-related outcomes in later life.