Association between polypharmacy and death: A systematic review and meta-analysis

Objective: Polypharmacy has been linked to a myriad of adverse consequences, and escalating rates of polypharmacy present an emerging concern, particularly among older adults. This systematic review and meta-analysis summarizes the existing literature concerning the association between polypharmacy and mortality.

Data sources: A systematic literature review was done by searching the EMBASE, PubMed, Scopus, and International Pharmaceutical Abstract databases to identify studies assessing the association between polypharmacy and death published until June 2016.

Study selection: Studies that investigated the association between polypharmacy and mortality were eligible for this systematic review and meta-analysis.

Data extraction: Data were extracted by the first and second authors independently using a data extraction form. Disagreement was resolved by consensus. A meta-analysis was performed using random effect models. Heterogeneity was assessed using the I² statistic.

Results: Forty-seven studies were included in this meta-analysis. The underlying populations were heterogeneous (I²= 91.5%). When defined as a discrete variable, pooled risk estimates demonstrated a significant association between polypharmacy and death (pooled-adjusted odds ratio [aOR] 1.08 [95% CI 1.04-1.12]). When defined categorically, a dose-response relationship was observed across escalating thresholds for defining polypharmacy. Categorical thresholds for polypharmacy using values of 1-4 medications, 5 medications, and 6-9 medications were significantly associated with death (P <0.05; aOR 1.24 [1.10-1.39], aOR 1.31 [1.17, 1.47], and aOR 1.59 [1.36-1.87], respectively). Excessive polypharmacy (ie, the use of 10 or more medications) was also associated with death (aOR 1.96 [1.42-2.71]).

Conclusions: Pooled risk estimates from this meta-analysis reveal that polypharmacy is associated with increased mortality risk, using both discrete and categorical definitions. The causality of this relationship remains unclear, but it emphasizes the need for approaches to health care delivery that achieve an optimal balance of risk and benefit in medication prescribing.