Sunday, June 17, 2012

Long-term risk of developing epilepsy after febrile seizures

A prospective cohort study

Long-term risk of developing epilepsy after febrile seizures

  1. J.W. Sander, PhD, FRCP
+Author Affiliations
  1. From the Department of Clinical and Experimental Epilepsy (A.N., G.S.B., C.G., S.D.S., J.W.S.), UCL Institute of Neurology, London, UK; MRC Biostatistics Unit (A.L.J.), Institute of Public Health, University Forvie Site, Cambridge, UK; MRC Clinical Trials Unit (A.L.J.), London, UK; Warders Medical Practice (D.M.G., former partner), Tunbridge Wells, Kent, UK; and SEIN-Epilepsy Institute in the Netherlands Foundation (J.W.S.), Heemstede, the Netherlands.
  1. Correspondence & reprint requests to Prof. Sander:


Objective: We report the prospective follow-up of a cohort of people from the onset of febrile seizures for a median of 24 years to estimate the long-term risk of developing epilepsy.
Methods: The National General Practice Study of Epilepsy is a large prospective community study of 1,195 people with a first suspected seizure followed from the 1980s, of whom 220 (18%) had febrile seizures. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) for subsequent epilepsy were calculated in 5-year age bands.
Results: Follow-up information was obtained for 181 (83%) people with a mean follow-up for the whole cohort of 21.6 (SD 6.0) years. Of these, 175 (97%) were seizure-free in the preceding 5 years, whereas 171 (94%) were seizure-free and off antiepileptic drugs. Six percent developed epilepsy, but the risk of developing epilepsy in the cohort over the whole follow-up period was almost 10 times that of the general population (SIR 9.7, 95% CI 5.7–16.4). The SIR was significantly elevated in the 0- to 14-year age groups but not in the 15- to 19-year age group (SIR 4.5, 95% CI 0.6–32.1).
Conclusion: The risk of developing epilepsy in people who had febrile seizures seems to decrease with time. Further long-term studies are needed to confirm this.

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