Duration of seizure-free period on therapy predicts subsequent recurrence

In adult patients with epilepsy, a seizure-free period on therapy of less than 2 years is associated with increased risk of recurrence, according to a study.

Researchers looked at the medical records of 133 seizure-free patients (52.6 percent male) with epilepsy who had discontinued treatment with antiepileptic drugs (AEDs). They assessed the frequency of seizure relapses after AED withdrawal and prognosis after recurrence, as well as evaluated the predictive role of baseline clinical and demographic variables.

The median duration of epilepsy in the cohort was 6 months, and the median age at last seizure was 34 years. Most of the patients had focal seizures (85.7 percent). Levetiracetam (30.1 percent) was the most frequently used AED, followed by carbamazepine (24.8 percent), valproic acid (13.5 percent), lamotrigine (11.3 percent), and phenobarbital (11.3 percent).

Over a median follow-up of 3 years (range, 0.8–33) after AED discontinuation, a total of 60 (45 percent) patients relapsed. Univariate analysis showed relapse to be associated with previous febrile seizures in childhood (hazard ratio [HR], 3.927, 95 percent confidence interval [CI], 1.403–10.988), a seizure-free period on therapy of less than 2 years (HR, 2.313, 95 percent CI, 1.193–4.486), and persistent motor deficits (HR, 4.568, 95 percent CI, 1.412–14.772).

However, only a seizure-free period on therapy of less than 2 years remained associated with seizure recurrence following adjustments for confounders (HR, 2.365, 95 percent CI, 1.178–4.7444).

Among patients who relapsed, epilepsy control was achieved with pharmacological treatment.