Association between polypharmacy and dementia – A systematic review and metaanalysis

Objective: The association between polypharmacy and dementia is controversial. This systematic review and meta-analysis aims to summarize existing literature concerning the association between polypharmacy and dementia.Methods: A systematic literature review was performed by searching the EMBASE, PubMed, Scopus and International Pharmaceutical Abstract databases using terms related to polypharmacy and dementia. A meta-analysis was performed using random effect models.Results: Seven studies were included in this meta-analysis. The included studies were of medium to high quality with a potential for publication bias. A strong association between polypharmacy and dementia was found (pooled adjusted risk ratio (aRR) = 1.30 (95% CI: 1.16–1.46), I2 = 68%). Excessive polypharmacy was also strongly associated with dementia (pooled aRR = 1.52 (95% CI: 1.39–1.67), I2 = 24%).Conclusion: Pooled risk estimates from this meta-analysis showed that polypharmacy was associated with dementia. Although the causality of the relationship cannot be concluded from this analysis, the finding encourages the use of multidimensional assessment tools for dementia that includes the number of medications as a component.