Clinical Features and Predictors of Unfavorable Outcomes in Infantile Epileptic Spasms Syndrome: Results from a Multiancestry Cohort

<b>Background:</b> Infantile epileptic spasms syndrome is an epileptic encephalopathy with poor prognosis. <b>Objective:</b> To describe clinical features and predictors of unfavorable outcomes of infantile epileptic spasms syndrome in a multiancestry cohort. <b>Methods:</b> Retrospective cross-sectional chart review analysis at a single tertiary pediatric hospital in 56 patients with infantile epileptic spasms syndrome. <b>Results:</b> Fifty-nine percent were males. Most patients (57%) were from the Middle East North African region. The mean age at onset of spasms was 6.6 months (±3.5 mo). At presentation, 80% of patients had a preexisting neurologic disorder, an abnormal development (66%), and/or an abnormal neurologic examination (73%). Hypsarrhythmia on electroencephalography (EEG) was reported in 55% of patients. Etiology was identified in 75%. Abnormalities on neuroimaging were common (70%), and 54% had abnormal genetic testing. The preferred first-line treatment was vigabatrin (66%) followed by high-dose oral steroids (16%). Only a minority (∼30%) experienced complete resolution of their epileptic spasms/hypsarrhythmia by 2 weeks. At the last follow-up, 84% of patients had an abnormal development and 40% were still on antiseizure medications. Comorbidities were common (75%). The majority of patients had unfavorable outcomes, including abnormal development (84%) and/or drug-resistant epilepsy (45%). Preexisting abnormal development/neurologic examination or neurologic conditions, perinatal risk factors, neuroimaging abnormalities, and an identified etiology were associated with increased odds ratios for unfavorable developmental outcomes or drug-resistant epilepsy. <b>Significance:</b> Clinical features and outcomes of infantile epileptic spasms syndrome in this multiancestry cohort confirms findings of previous epidemiologic studies, recognizes some differences, and highlights risk factors that can be used for early identification of patients with predicted unfavorable outcomes.