Predictors of referral for long‐term EEG monitoring for Medicare beneficiaries with drug‐resistant epilepsy

OBJECTIVE: For people with drug‐resistant epilepsy, the use of epilepsy surgery is low despite favorable odds of seizure freedom. To better understand surgery utilization, we explored factors associated with inpatient long‐term EEG monitoring (LTM), the first step of the presurgical pathway. METHODS: Using 2001–2018 Medicare files, we identified patients with incident drug‐resistant epilepsy using validated criteria of ≥2 distinct antiseizure medication (ASM) prescriptions and ≥1 drug‐resistant epilepsy encounter among patients with ≥2 years pre‐ and ≥1 year post‐diagnosis Medicare enrollment. We used multilevel logistic regression to evaluate associations between LTM and patient, provider, and geographic factors. We then analyzed neurologist‐diagnosed patients to further evaluate provider/environmental characteristics. RESULTS: Of 12 044 patients with incident drug‐resistant epilepsy diagnosis identified, 2% underwent surgery. Most (68%) were diagnosed by a neurologist. In total, 19% underwent LTM near/after drug‐resistant epilepsy diagnosis; another 4% only underwent LTM much prior to diagnosis. Patient factors most strongly predicting LTM were age <65 (adjusted odds ratio 1.5 [95% confidence interval 1.3–1.8]), focal epilepsy (1.6 [1.4–1.9]), psychogenic non‐epileptic spells diagnosis (1.6 [1.1–2.5]) prior hospitalization (1.7, [1.5–2]), and epilepsy center proximity (1.6 [1.3–1.9]). Additional predictors included female gender, Medicare/Medicaid non‐dual eligibility, certain comorbidities, physician specialties, regional neurologist density, and prior LTM. Among neurologist‐diagnosed patients, neurologist <10 years from graduation, near an epilepsy center, or epilepsy‐specialized increased LTM likelihood (1.5 [1.3–1.9], 2.1 [1.8–2.5], 2.6 [2.1–3.1], respectively). In this model, 37% of variation in LTM completion near/after diagnosis was explained by individual neurologist practice and/or environment rather than measurable patient factors (intraclass correlation coefficient 0.37). SIGNIFICANCE: A small proportion of Medicare beneficiaries with drug‐resistant epilepsy completed LTM, a proxy for epilepsy surgery referral. While some patient factors and access measures predicted LTM, non‐patient factors explained a sizable proportion of variance in LTM completion. To increase surgery utilization, these data suggest initiatives targeting better support of neurologist referral.