Systematic Review and Meta-Analysis on the Associations of Polypharmacy and Potentially Inappropriate Medication With Adverse Outcomes in Older Cancer Patients

Abstract

Background: Both polypharmacy and potentially inappropriate medication (PIM) intake are highly prevailing in older cancer patients. However, only studies on the association of polypharmacy and postoperative complications have been meta-analyzed previously.

Methods: A systematic review and a meta-analysis of prospective/retrospective observational studies reporting associations of polypharmacy or PIM with at least one out of five predefined adverse health outcomes in a population of older cancer patients (≥60 years) were carried out. PubMed and Web of Science were used to search for relevant studies published between January 1991 and March 2020. Data were pooled by adopting a random-effects model.

Results: Overall, 42 publications were included in the systematic review. Meta-analyses could be performed on 39 studies about polypharmacy and 13 studies about PIM. Polypharmacy was found to be statistically significantly associated with all-cause mortality (risk ratio [95% confidence interval]: 1.37 [1.25-1.50]), hospitalization (1.53 [1.37-1.71]), treatment-related toxicity (1.22 [1.01-1.47]), and postoperative complications (1.73 [1.36-2.20]). The association of polypharmacy with prolongation of hospitalization was not statistically significant at the p < .05 significance level (1.62 [0.98-2.66]). With respect to PIM, a statistically significant association with all-cause mortality (1.43 [1.08-1.88]) was observed but not with other adverse outcomes.

Conclusions: Polypharmacy was found to be associated with several adverse outcomes and PIM use with all-cause mortality in older cancer patients. However, these results should be interpreted with caution because about three-quarters of the studies identified did not adjust for comorbidity and are prone to confounding by indication.

Keywords: Adverse drug reaction; Geriatric oncology; Hospitalizations; Mortality; Postoperative complications.