Complete remission in nonsyndromic childhood-onset epilepsy

Abstract

Objective: Determine the probability of attaining complete remission in children with nonsyndromic epilepsy (NSE) over the course of ≥10 years from initial diagnosis; identify early predictors of complete remission; and assess the risk of relapse after achieving complete remission.

Methods: In a prospective community-based cohort, complete remission was defined as 5 years seizure-free and medication-free. Any subsequent seizure for any reason was a relapse. Univariate and bivariate analyses were conducted with standard methods including the Kaplan-Meier approach. Proportional hazards modeling was used for multivariable analysis.

Results: Of 613 cohort members, 347 had NSEs, of whom 294 (85%) were followed ≥10 years (maximum = 17.9). A total of 170 in 294 (58%) achieved complete remission, 10 of whom (6%) relapsed. Seizure outcome at 2 years (remission, pharmacoresistant, unclear) (p < 0.0001) and underlying cause (p < 0.0001) distinguished groups with complete remission ranging from ~20% to ~75%. Older age at onset was independently associated with a poorer chance of complete remission. Relapses occurred up to 7.5 years after attaining complete remission and were marginally associated with underlying cause (p = 0.06).

Interpretation: Complete remission occurs in over one-half of young people with NSE and generally persists. Meaningful but imperfect predication is possible based on underlying cause and early seizure control. The finding of age effects may play a role in meaningful identification of phenotypes, which could become fruitful targets for genetic and imaging investigations in these otherwise poorly differentiated epilepsies.

Figure 1

Cumulative probability of (a) attaining complete remission and of (b) relapse after remission

Figure 2

Complete remission as a function of early seizure outcome: remission at two years (---), unclear, (....) and pharmacoresistant (—)

Figure 3

Complete remission as a function of the presence or absence of an underlying brain disorder: no identified underlying disorder (....) and underlying disorder identified (—).

Figure 4

Cumulative probability of attaining complete remission in those (a) without and (b) with an underlying brain disorder as a function of early seizure outcomes: remissions at two years (---), unclear, (....) and pharmacoresistant (—)