Polypharmacy burden and incident epilepsy among older adults in the United States

OBJECTIVES: To estimate the prevalence of polypharmacy among older adults with incident epilepsy and to describe the most common combinations of drug classes filled prior to epilepsy diagnosis. Polypharmacy-the concurrent use of multiple medications-is common in older adults with epilepsy, but little is known about its burden and specific patterns at the time of diagnosis. METHODS: This retrospective longitudinal cohort study included 2 768 656 US Medicare beneficiaries aged 67 and older with Part D coverage. Beneficiaries were epilepsy-free from 2016 to 2018; 13 819 (0.5%) were newly diagnosed with epilepsy in 2019. The prevalence of polypharmacy and combinations of therapeutic drug classes filled in 2018 were compared between those with and without incident epilepsy using frequent itemset mining and regression models to estimate adjusted rate ratios. RESULTS: Beneficiaries with incident epilepsy filled prescriptions for a greater number of therapeutic drug classes in the year prior to diagnosis compared with those without epilepsy (median 9 [IQR 5-12] vs. 6 [IQR 3-9]) and were more likely to have filled prescriptions for five or more distinct drug classes (81.4% vs. 63.3%). Antidepressants, gastric medications, and loop diuretics were more prevalent among beneficiaries with incident epilepsy. The combination of calcium channel blockers and antihypertensives was most strongly associated with incident epilepsy after adjustment (adjusted rate ratio 1.54 [99% CI, 1.38-1.71]). SIGNIFICANCE: Older adults with incident epilepsy experience a high burden of polypharmacy at the time of diagnosis, with nearly 90% prescribed five or more drug classes. Certain drug class combinations, such as antipsychotics and antidepressants, were more frequently observed among those with incident epilepsy. These findings underscore the importance of considering overall polypharmacy burden and specific drug class combinations when initiating epilepsy therapy in older adults. PLAIN LANGUAGE SUMMARY: Older adults who develop epilepsy often take many medications for other health conditions. In this study of US Medicare beneficiaries, people who were later diagnosed with epilepsy were taking about nine different types of drug classes in the year before diagnosis, compared with about six drug classes among those who did not develop epilepsy. Certain combinations of drug classes-especially those affecting the brain and nervous system-were more common among people who developed epilepsy. These findings show that many older adults have complex medication regimens when epilepsy is first diagnosed.