Association Between Characteristics of National Association of Epilepsy Centers and Reported Utilization of Specific Surgical Techniques

Abstract

Background and objective: Nearly one-third of persons with epilepsy will continue having seizures despite trialing multiple antiseizure medications. Epilepsy surgery may be beneficial in these cases, and evaluation at a comprehensive epilepsy center is recommended. Numerous palliative and potentially curative approaches exist, and types of surgery performed may be influenced by center characteristics. This article describes epilepsy center characteristics associated with epilepsy surgery access and volumes in the United States.

Methods: We analyzed National Association of Epilepsy Centers 2019 annual report and supplemental survey data obtained with responses from 206 adult epilepsy center directors and 136 pediatric epilepsy center directors in the United States. Surgical treatment volumes were compiled with center characteristics, including US Census region. We used multivariable modeling with zero-inflated Poisson regression models to present ORs and incidence rate ratios of receiving a given surgery type based on center characteristics.

Results: The response rate was 100% with individual element missingness less than 4% across 352 observations undergoing univariate analysis. Multivariable models included 319 complete observations. Significant regional differences were present. The rates of laser interstitial thermal therapy (LITT) were lower at centers in the Midwest (incidence rate ratio [IRR] 0.74, 95% CI 0.59-0.92; p = 0.006) and Northeast (IRR 0.77, 95% CI 0.61-0.96; p = 0.022) compared with those in the South. Conversely, responsive neurostimulation implantation rates were higher in the Midwest (IRR 1.45, 95% CI 1.1-1.91; p = 0.008) and West (IRR 1.91, 95% CI 1.49-2.44; p < 0.001) compared with the South. Center accreditation level, institution type, demographics, and resources were also associated with variations in access and rates of potentially curative and palliative surgical interventions.

Discussion: Epilepsy surgery procedure volumes are influenced by US epilepsy center region and other characteristics. These variations may affect access to specific surgical treatments for persons with drug resistant epilepsy across the United States.

Figure 1. Forest Plot for OR (Zero-Inflated Component) of Potentially Curative Treatment Models

Several independent variables were excluded by the model selection process using the AIC criteria, and some were manually removed because of imbalance between categories (see Supplementary Tables, links.lww.com/WNL/C466). Box indicates a statistically significant value (p ≤ 0.05). Abbreviation: AIC = Akaike information criterion.

Figure 2. Forest Plot for Incidence Rate Ratio (Count Component) of Potentially Curative Treatment Models

Several independent variables were excluded by the model selection process using the AIC criteria, and some were manually removed because of imbalance between categories (see eTables 1–4, links.lww.com/WNL/C466). Box indicates a statistically significant value (p ≤ 0.05). Abbreviation: AIC = Akaike information criterion.

Figure 3. Forest Plot for OR (Zero-Inflated Component) of Palliative Treatment Models

Several independent variables were excluded by the model selection process using the AIC criteria, and some were manually removed because of imbalance between categories (see eTables 1–4, links.lww.com/WNL/C466). Box indicates a statistically significant value (p ≤ 0.05). Abbreviation: AIC = Akaike information criterion.

Figure 4. Forest Plot for Incidence Rate Ratio (Count Component) of Palliative Treatment Models

Several independent variables were excluded by the model selection process using the AIC criteria, and some were manually removed because of imbalance between categories (see eTables 1–4, links.lww.com/WNL/C466). Box indicates a statistically significant value (p ≤ 0.05). Abbreviation: AIC = Akaike information criterion.