Purpose: To estimate the rate of new-onset afebrile provoked and unprovoked seizure in a general pediatric population and subgroups of patients with and without psychiatric diagnoses other than attention deficit hyperactivity disorder (ADHD). Methods: A retrospective cohort study of 133,440 pediatric patients, between the ages of 6 and 17 years, and without history of seizure or prior use of anticonvulsant medications, with follow-up during 2003. The data source for this study was Ingenix's research database containing pharmacy and medical claims for members of a large US-based managed care organization. The main outcome measure was new-onset nonfebrile seizure. Incidence rates of seizure and 95% confidence intervals (CI) were calculated and expressed as rates per 100,000 person-years. Results: There were 132 new-onset provoked and unprovoked seizures in 78,423 person-years of follow-up among the general pediatric population sample. The incidence rate of seizure among the general pediatric population was 168 per 100,000 p-y (95% CI 141-200). The incidence rate of seizure among patients without psychiatric diagnoses was 149 per 100,000 p-y (95% CI 122-180). The incidence rate of seizure among patients with psychiatric diagnoses other than ADHD was 513 per 100,000 p-y (95% CI 273-878). There were increases in the incidence rates of seizure in all of the seizure risk factor groups, but this was more pronounced among males ages 6-12 with psychiatric diagnoses. Conclusions: The results of this study are consistent with previous reports showing that pediatric patients with psychiatric disorders have a higher incidence rate of seizure than the general pediatric population.
