Abstract
PURPOSE: We examined the association between polypharmacy-an established risk factor for nonadherence in the elderly-and medication fill nonadherence in a large national sample of adolescent and young adult cancer survivors (AYAs) in the USA. METHODS: We pooled data (2008-2017) from the Medical Expenditure Panel Survey. We defined polypharmacy as ≥ 3 unique medications prescribed, based on self-report and pharmacy data, and medication fill nonadherence as self-reported delay or inability to obtain a necessary medication. We estimated prevalence of medication fill nonadherence among AYAs (age 18-39 years with a cancer history). We used logistic regression to estimate the association between (1) polypharmacy and medication fill nonadherence in AYAs, and (2) total number of medications prescribed and medication fill nonadherence, controlling for sex, number of chronic conditions, disability, and survey year. RESULTS: AYAs (n = 598) were predominantly female (76.2%), age 30-39 years (64.9%), and non-Hispanic White (72.1%). Nearly half were poor (19.0%) or near-poor/low income (21.6%). One in ten AYAs reported medication fill nonadherence (9.75%). Of these, more than 70% cited cost-related barriers as the reason. AYAs with polypharmacy had 2.49 times higher odds of medication fill nonadherence (95%CI 1.11-5.59), compared to those without polypharmacy. Odds of medication fill nonadherence increased by 16% with each additional medication prescribed (AOR 1.16, 95% CI 1.07-1.25). CONCLUSIONS: Polypharmacy may be an important risk factor for medication fill nonadherence in AYAs in the USA. IMPLICATIONS FOR CANCER SURVIVORS: Improving AYAs' medication adherence requires eliminating cost-related barriers, particularly for those with polypharmacy.