Association of inappropriate polypharmacy with emergency department visits in older patients receiving anti-neoplastic therapy: a population-based study.

We aimed to investigate the prevalence and predicting factors of inappropriate polypharmacy including potentially inappropriate medications (PIMs) and drug-drug interactions (DDIs) and their associations with emergency department (ED) visits in older Korean patients receiving anti-neoplastic therapy.
We identified older patients receiving anti-neoplastic therapy in 2016 from the National Health Claims database. We investigated the prevalence of inappropriate polypharmacy comprising PIMs and DDIs in geriatric patients according to the 2019 American Geriatrics Society Beers Criteria and chemotherapeutic DDIs using Lexicomp Online and Micromedex. A nested case-control study was conducted to evaluate the associations between inappropriate polypharmacy and ED visits during anti-neoplastic therapy. Multivariate logistic regressions were performed after adjusting for age, sex, cancer diagnosis, prior ED visits, Charlson Comorbidity Index, and type of anti-neoplastic therapy.
Inappropriate polypharmacy, its subtype PIMs, geriatric, and chemotherapeutic DDIs were observed in 85.4%, 80.4%, 17.3%, and 37.9% of the 21,956 patients receiving anti-neoplastic therapy, respectively. After adjusting for confounding factors, the presence of inappropriate polypharmacy (adjusted odds ratio (aOR) 2.15, 95% confidence interval (CI) 1.97-2.35), 2 or more PIMs (aOR 1.85, 95% CI 1.68-2.02), 2 or more chemotherapeutic DDIs (aOR 2.88, 95% CI 2.54-3.28), and geriatric DDIs (aOR 1.61, 95% CI 1.43-1.80) increased the likelihood of ED visits during anti-neoplastic therapy.
This nationwide study showed that inappropriate polypharmacy was prevalent and increased the risk of ED visits in older patients receiving anti-neoplastic therapy. Study findings suggested a need to implement deprescribing strategies in this population.