Polypharmacy and out-of-pocket medication costs in the last month of life among commercially insured patients with advanced cancer: Insights from linking a regional cancer registry and insurance claims.

79Background: Polypharmacy, defined as the concurrent use of multiple medications, may expose patients to drug-drug interactions and excessive medication costs. Patients with advanced cancer may benefit from medication discontinuation when faced with life-limiting illness. While polypharmacy prevalence has been explored in older patients, there are limited data for younger patients with advanced malignancy. To better understand medication use in this population, we characterized medication use and associated out-of-pocket (OOP) costs in the last month of life among commercially insured subjects under age 65 who did not enroll in hospice. Methods: We linked enrollment and claims records from two regional commercial insurers to Surveillance, Epidemiology, and End Results (SEER) Cancer Surveillance System and Washington State Cancer Registry records for patients diagnosed with a stage IV solid tumor malignancy in Washington state between January 1, 2007-December 31, 2016. We excluded patients who did not inc...