Cognitive disorders in childhood epilepsy: a comparative longitudinal study using administrative healthcare data

OBJECTIVE: The study aimed to assess the risk of cognitive impairment in patients with epilepsy, the impact of age of epilepsy onset on cognition and the temporal relationship of epilepsy onset and intellectual impairment. METHODS: This longitudinal study analyzed birth cohorts and followed-up children born 2005–2007 up to the age of ten using administrative healthcare data of about 8.9 million members insured by the statutory health insurance “BARMER” in Germany. We compared prevalence of cognitive impairment (ICD-code F7*) in children with epilepsy (ICD-code G40) to controls, and calculated relative risks by age groups at onset of epilepsy and assessed differences in relation to the temporal sequence of the diagnoses. RESULTS: Of the 142,563 pre-pubertal children included in the analysis, 2728 (1.9%) had an epilepsy diagnosis within the first 10 years of life. 17.4% (475/2728) of children with epilepsy had a diagnosis of cognitive impairment compared to 1.7% (2309/139835) in controls. The relative risk for cognitive impairment compared to age-matched controls was 10.5 (95% CI 9.6, 11.6) and was highest in epilepsy cases with seizure manifestation within the first 2 years of life compared to older children. The prevalence of cognitive impairment before epilepsy diagnosis was slightly increased compared to controls, while it was increased by a factor of nine in children diagnosed with cognitive impairment in the year of onset of epilepsy or afterwards. CONCLUSIONS: Pre-pubertal children with epilepsy have a ten-fold higher risk for intellectual impairment compared to age-matched controls. This risk inversely correlates with the age of epilepsy manifestation. Cognitive impairment was diagnosed after epilepsy manifestation in the majority of patients.