Source: OpenUrlAbstract/FREE Full Text
Investigators from multiple institutions analyzed data from the Norwegian Mother and Child Cohort Study (MoBa) to assess shortterm seizure outcomes in children with epilepsy (CWE). MoBa is a nationwide cohort study of children born in Norway between 1999 and 2009. For the current study, the authors reviewed data from the Epilepsy in Young Children Study, which was embedded in MoBa. CWE were identified through linkage with the Norwegian Patient Registry and parental reports in periodic questionnaires; medical record review and parental interviews were used to capture clinical information about seizures and treatments. Only children with at least 1 year of follow-up were included in the analyses. The primary study outcome was drug-resistant epilepsy (DRE), defined as seizures within the last year of patient follow-up despite trials of at least 2 antiepileptic drugs. Participants without a seizure for >1 year were classified as seizure-free, and those with a seizure within the last year of follow-up who had not completed trials of >2 drugs were classified as having intermediate outcomes. Chi-square tests and regression analyses (with adjustment for confounders) were used to identify risk factors for DRE. Risk factors assessed included type of seizures, identifiable cause, preterm birth, age at onset <1 year old, family history of seizures, and additional neurologic or developmental difficulties. Because of the large number of risk factors assessed, P values <.01 were classified as statistically significant, and the 99% CI was used to assess relative risk (RR) estimates.
Among 112,745 children in the MoBa cohort, 600 CWE with >1 year of follow-up were identified. The median age of epilepsy onset among these 600 children was 3 years, and median follow-up period was 6 years. Of the 600 CWE, 178 (30%) had DRE, 353 (59%) were seizure-free, and 69 (12%) had intermediate outcomes. Among children with an identifiable cause for seizures (structural, genetic, metabolic, or infectious), 48% had DRE compared to 21% in those without an identifiable cause (RR=2.7; 99% CI, 1.8, 3.9). In CWE without an identifiable cause, >3 types of seizures and an additional neurologic or developmental difficulty were both associated with increased risk of DRE (RR=3.5; 99% CI, 2.1, 5.9 and RR=2.0; 99% CI, 1.1, 3.8, respectively), while family history of seizures, preterm birth, and age of onset <1 year of age were not statistically associated with an increased risk. Among specific seizure classifications, tonic seizures and epileptic spasms were independently associated with DRE in children without an identifiable cause for their epilepsy (RR=1.6; 99% CI, 1.0, 2.7 and RR=1.8; 99% CI, 1.2, 2.8, respectively).
The authors conclude that drug resistance occurs in 30% of CWE; having an identifiable cause of epilepsy is associated with DRE.
Commentary
Dr Urion has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.
Freedom from seizures in a child with epilepsy is the ultimate goal of providers and families; the likelihood of achieving this goal is one of the first questions asked by families. To date, relatively few studies have addressed this effectively or with reliable statistical methods. In the 1990s, the Camfields and colleagues published a population-based study of childhood epilepsy in Nova Scotia.1 Their data suggested that 70% of all children presenting with epilepsy achieved seizure freedom, defined in a fashion similar to the criteria used in the current study, and the demographic data they could glean suggested that best predictors of ultimate seizure freedom were onset before age 12 years, an absence of a history of neonatal seizures, intelligence within the range of normal, and <21 seizures before treatment initiation.
The current investigators found a similar percentage of children with epilepsy ultimately achieved seizure freedom as that described by the Camfields. Unlike the Camfields, the current investigators were able to associate DRE with a known cause of epilepsy (eg, structural lesion, metabolic disorder, genetic condition, or history of significant infection). It is likely that in the Camfields’ study, the predictive factor of lower intelligence served as a proxy for these conditions, since they all increase the risk of developmental difficulties and poorer neurocognitive outcomes.2
The other factors associated with DRE (≥3 seizure types, associated neurodevelopmental difficulties) also coincide with elements seen in other demographic studies.3 The current study included a larger number of children than prior ones. The similarity of results in this more robust sample therefore also gives us confidence that the predictions we have been offering families over the last several decades are sound and accurate.
Bottom Line
Seizure freedom is achieved by 70% of children with epilepsy. Those with DRE are predicted by multiple seizure semiologies, the presence of a known causative condition or event (infectious, metabolic, structural, or genetic), or the independent existence of neurodevelopmental delay. (See related article AAP Grand Rounds, 2018;39[5]:52.4)
In this issue
Related Articles
Cited By...
- No citing articles found.