Long-term seizure remission in childhood absence epilepsy: Might initial treatment matter?

Authors

  • Anne T. Berg,

    Corresponding author
    1. Department of Pediatrics, Epilepsy Center, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, U.S.A
    2. the Northwestern Memorial Feinberg School of Medicine, Chicago, Illinois, U.S.A
    • Address correspondence to Anne T. Berg, Ann & Robert H. Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, 225 East Chicago Avenue, Box 29, Chicago, IL 60611-2605, U.S.A. E-mail: atberg@luriechildrens.org

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  • Susan R. Levy,

    1. Department of Neurology, Yale School of Medicine, New Haven, Connecticut, U.S.A
    2. Department of Pediatrics, Yale School of Medicine, New Haven, Connecticut, U.S.A
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  • Francine M. Testa,

    1. Department of Neurology, Yale School of Medicine, New Haven, Connecticut, U.S.A
    2. Department of Pediatrics, Yale School of Medicine, New Haven, Connecticut, U.S.A
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  • Hal Blumenfeld

    1. Department of Neurology, Yale School of Medicine, New Haven, Connecticut, U.S.A
    2. Department of Neurobiology, Yale School of Medicine, New Haven, Connecticut, U.S.A
    3. Department of Neurosurgery, Yale School of Medicine, New Haven, Connecticut, U.S.A
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Summary

Objective

Examine the possible association between long-term seizure outcome in childhood absence epilepsy (CAE) and the initial treatment choice.

Methods

Children with CAE were prospectively recruited at initial diagnosis and followed in a community-based cohort study. Children presenting with convulsive seizures, significant imaging abnormalities, or who were followed <5 years were excluded. Early outcomes included success of initial medication, early remission, and pharmacoresistance. The primary long-term outcome was complete remission: ≥5 years both seizure free and medication free. Survival methods were used for analyses.

Results

The first medication was ethosuximde (ESM) in 41 (69%) and valproic acid (VPA) in 18 (31%). Initial success rates were 59% (ESM) and 56% (VPA). Early remission and pharmacoresistance were similar in each group. Apart from atypical electroencephalography (EEG) features (61% [VPA], 17% [ESM]), no clinical features varied substantially between the treatment groups. Complete remission occurred in 31 children (76%) treated with ESM and 7 (39%) who received VPA (p = 0.007). Children with versus without atypical EEG features were less likely to enter complete remission (50% vs. 71%, p = 0.03). In a Cox regression, ESM was associated with a higher rate of complete remission than VPA (hazards ratio [HR] 2.5, 95% confidence interval [CI] 1.1–6.0; p = 0.03). Atypical EEG features did not independently predict outcome (p = 0.15). Five-year and 10-year remission, regardless of continued treatment, occurred more often in children initially treated with ESM versus VPA.

Significance

These findings are congruent with results of studies in genetic absence models in rats and provide preliminary evidence motivating a hypothesis regarding potential disease-modifying effects of ESM in CAE.

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