ASPO Abstracts
Polypharmacy and patterns of prescription medication use among cancer survivors
Category: Survivorship & Health Outcomes/Comparative Effectiveness Research, Lifestyles Behavior, Energy Balance & Chemoprevention
Conference Year: 2018
Abstract Body:
Background: The population of cancer survivors is rapidly growing in the U.S. Long-term and late effects of cancer, combined with ongoing management of other chronic conditions, make survivors particularly vulnerable to polypharmacy and its adverse effects. We examined patterns of prescription medication use and polypharmacy in a population-based sample of cancer survivors and adults without cancer. Methods: Using data from the Medical Expenditures Panel Survey (MEPS), we matched cancer survivors (n=5,216) to non-cancer controls (n=19,588) by age, sex, and survey year. We defined polypharmacy as using five or more unique medications. We examined the proportion of respondents prescribed specific medications within first-, second-, and third-level therapeutic classes and compared these proportions by time since diagnosis. We also estimated total annual expenditures from prescription medications, including both out-of- pocket payments and payments made by insurance. Results: A higher proportion of cancer survivors were prescribed five or more unique medications (64.0%, 95% CI 62.3 — 65.8%) compared to non-cancer controls (51.5%, 95% CI 50.4 — 52.6%), including drugs with abuse potential. Across all therapeutic classes, a higher proportion of newly (‰¤1 year since diagnosis) and previously (>1 year since diagnosis) diagnosed survivors were prescribed medications compared to controls, with large differences in central nervous system agents (65.8% vs. 57.4% vs. 46.2%), psychotherapeutic agents (25.4% vs. 26.8% vs. 18.3%), cardiovascular agents (62.2% vs. 59.1% vs. 52.4%), and gastrointestinal agents (31.9% vs. 29.6% vs. 22.0%). Specifically, nearly 10% of survivors were prescribed benzodiazepines and/or opioids compared to about 5% of controls. Survivors also had more than double prescription expenditures (median $1,633 vs. $784 among non-cancer controls). These findings persisted similarly across categories of age and comorbidity. Conclusion: Cancer survivors were prescribed a higher number of unique medications and inappropriate medications or drugs with abuse potential, increasing risk of adverse drug events, financial toxicity, poor adherence, and drug-drug interactions. Adolescent and young adult survivors appear at increased risk of polypharmacy.
Keywords: Survivorship, population- based, prescription drugs