Health outcomes associated with polypharmacy in community-dwelling older adults: a systematic review

Objectives: To summarize evidence regarding the health outcomes associated with polypharmacy, defined as number of prescribed medications, in older community-dwelling persons.

Design: Systematic review of MEDLINE (OvidSP 1946 to May, Week 3, 2014).

Setting: Community.

Participants: Observational studies examining health outcomes according to number of prescription medications taken.

Measurements: Association between number of medications and health outcomes. Because of the importance of comorbidity as a potential confounder of the relationship between polypharmacy and health outcomes, articles were assessed regarding the quality of their adjustment for confounding.

Results: Of the 50 studies identified, the majority that were rated good in terms of their adjustment for comorbidity demonstrated relationships between polypharmacy and a range of outcomes, including falls, fall outcomes, fall risk factors, adverse drug events, hospitalization, mortality, and measures of function and cognition. However, a number of these studies failed to demonstrate associations, as did a substantial proportion of studies rated fair or poor.

Conclusion: Data are mixed regarding the relationship between polypharmacy, considered in terms of number of medications, and adverse outcomes in community-dwelling older persons. Because of the challenge of confounding, randomized controlled trials of medication discontinuation may provide more-definitive evidence regarding this relationship than observational studies can provide.