Use of Recommended Neurodiagnostic Evaluation among Patients with Drug Resistant Epilepsy in the US: A Common Data Model Study of Multiple Large Databases

Introduction: Interdisciplinary practice parameters recommend that patients with drug-resistant epilepsy (DRE) undergo comprehensive neurodiagnostic evaluation, including presurgical assessment. Specialized centers have reported delays in referrals and underutilization of surgery; however, data are limited in more diverse populations. We aimed to determine the rate and predictors of neurodiagnostic studies and comprehensive evaluation among patients with DRE within 3 US cohorts.

Methods: This was a retrospective cross-sectional study using the Observational Medical Outcomes Partnership (OMOP) Common Data Model. We examined US multi-state Medicaid, commercial claims, and academic medical center (AMC) electronic health record-derived data. Participants included patients meeting a previously validated computable phenotype for DRE, at or prior to a clinical encounter between 2015 and 2020. The primary outcome was the proportion of patients receiving a composite proxy for comprehensive neurodiagnostic evaluation, including: (1) magnetic resonance or other advanced brain imaging, (2) video electroencephalogram (EEG), and (3) neuropsychological evaluation within 2 years of meeting the inclusion criteria.

Results: In the Medicaid cohort, 4.5% (1,520/11,955) met the comprehensive evaluation criteria within 2 years, compared to 8.0% (1,796/9,773) in the commercial insurance cohort, and 14.3% (393/1,443) in the AMC cohort. Video EEG (24.9% Medicaid, 28.4% Commercial, 63.2% AMC) and MRI brain (35.6% Medicaid, 43.4% Commercial, 52.6% AMC) were performed more frequently than neuropsychological evaluation (13.0% Medicaid, 16.6% Commercial, 19.2% AMC) or advanced imaging (3.2% Medicaid, 5.4% Commercial, 13.1% AMC). Factors associated with higher odds of evaluation included inpatient and outpatient non-emergency visit frequency and focal rather than generalized epilepsy.

Conclusion : There is a significant gap in the use of diagnostic studies to evaluate patients with drug resistant epilepsy. Care setting, insurance type, frequency of non-emergency visits, and epilepsy type are all associated with evaluation. A common data model can be used to measure adherence with best practices across a variety of observational data sources.