Polypharmacy composition and patient- and provider-related variation in patients with epilepsy
Highlights
- •
We performed a retrospective analysis of patients with epilepsy in Medicare.
- •
Polypharmacy was common (median 12 medications, 60% CNS polypharmacy).
- •
Hydrocodone/acetaminophen was the second most common medication.
- •
Provider differences explained more variation than patient differences in fills.
- •
Future work should study drivers of high-prescribing practices.
Abstract
Objective
To describe polypharmacy composition, and the degree to which patients versus providers contribute to variation in medication fills, in people with epilepsy.
Methods
We performed a retrospective study of Medicare beneficiaries with epilepsy (antiseizure medication plus diagnostic codes) in 2014 (N = 78,048). We described total number of medications and prescribers, and specific medications. Multilevel models evaluated the percentage of variation in two outcomes (1. number of medications per patient-provider dyad, and 2. whether a medication was filled within thirty days of a visit) due to patient-to-patient differences versus provider-to-provider differences.
Results
Patients filled a median of 12 (interquartile range [IQR] 8–17) medications, from median of 5 (IQR 3–7) prescribers. Twenty-two percent filled an opioid, and 61% filled at least three central nervous system medications. Levetiracetam was the most common medication (40%), followed by hydrocodone/acetaminophen (27%). The strongest predictor of medications per patient was Charlson comorbidity index (7.5 [95% confidence interval (CI) 7.2–7.8] additional medications for index 8+ versus 0). Provider-to-provider variation explained 36% of variation in number of medications per patient, whereas patient-to-patient variation explained only 2% of variation. Provider-to-provider variation explained 57% of variation in whether a patient filled a medication within 30 days of a visit, whereas patient-to-patient variation explained only 30% of variation.
Conclusion
Patients with epilepsy fill a large number of medications from a large number of providers, including high-risk medications. Variation in medication fills was substantially more related to provider-to-provider rather than patient-to-patient variation. The better understanding of drivers of high-prescribing practices may reduce avoidable medication-related harms.