Vagus nerve stimulation for drug-resistant epilepsy and predictors for seizure freedom: A nationwide multicenter cohort study in Mexico.

OBJECTIVE

To evaluate clinical outcomes, treatment response and predictors of seizure freedom after vagus nerve stimulation in patients with drug-resistant epilepsy in a Mexican cohort.

METHODS

We conducted a retrospective multicenter cohort across 13 epilepsy centers in Mexico (2003-2024) including patients aged ≥4 years with drug-resistant epilepsy or epileptic encephalopathy. Treatment response was defined as at least 50% seizure reduction and Engel outcomes. Logistic regression identified predictors of seizure freedom. Model performance was assessed with receiver operating characteristic analysis, area under the curve, Hosmer-Lemeshow test, and a confusion matrix.

RESULTS

Ninety-three patients (51 children, 42 adults) were included. At 1 year, median monthly seizure frequency decreased by 82.5% (40-7; p < .001). The incidence of status epilepticus declined by 92.8%, acute prolonged seizures by 80.9%, the burden of antiseizure medications by 25%, and epilepsy-related hospitalizations by 100% (all p < .001). Overall, 68.8% achieved ≥50% reduction and 11.8% became seizure-free. On univariate analysis, comorbidities, multiple seizure types, higher baseline seizure frequency, greater number of antiseizure medications, and magnet use were inversely related to seizure freedom, while normal brain MRI showed a direct relationship. On multivariable analysis, only baseline seizure frequency ≥30/month independently predicted seizure freedom (p = .047), corresponding to 97.7% lower odds. A predictive model incorporating comorbidities and number of antiseizure medications improved discrimination (p < .001) with 86.6% sensitivity and 81.8% specificity.

SIGNIFICANCE: Vagus nerve stimulation was associated with substantial seizure frequency reduction, lower morbidity, and less healthcare utilization, with a favorable safety profile. Baseline seizure burden emerged as the key predictor of seizure freedom and may guide patient selection, supporting earlier vagus nerve stimulation consideration in drug-resistant epilepsy.