title: Inpatient admission for febrile seizure and subsequent outcomes do not differ in children with vaccine-associated versus non-vaccine associated febrile seizures.
abstract: BACKGROUND
  Recent data suggest that the risk factors for febrile seizure (FS) can differ depending on whether the FS was vaccine-associated (VA) or not. As such, there also may be differences in the risk of inpatient admission and/or the incidence of FS-related subsequent outcomes following the index FS depending on whether it was VA or non-vaccine associated (NVA). This could have useful clinical implications including caregiver education and planning for follow-up care.
  
  
  METHODS
  This cohort study consisted of 3348 children who experienced an index FS between 6 months up to 3 years of age from July 1, 2003 through December 31, 2011. The index FS was determined to be VA-FS or NVA-FS; inpatient admission for FS, recurrent FS, and diagnosis of epilepsy were compared between exposure groups. Hazard ratios and relative risk estimates comparing between VA-FS and NVA-FS were estimated by Cox proportional models and Robust Poisson regression models, adjusted for race, sex, age at first FS, birth weight, gestational age, maternal age, and 1- and 5-min Apgar scores.
  
  
  RESULTS
  The mean age at index FS was 1.5 years; the mean length of follow-up was 2.3 years. Of all index FS, 383 (11.4%) were VA and 2965 were NVA. Among index FS, 264 (7.9%) were admitted as inpatients. Subsequently, 703 (21.0%) children developed at least one recurrent FS, where the number of recurrences ranged from 0 to 9 events. Overall, 144 (4.3%) children were diagnosed with epilepsy during the follow-up period. In adjusted analyses, VA-FS did not differ in the risk for any of the outcomes of interest compared with NVA-FS.
  
  
  CONCLUSIONS
  The risk of hospitalization for index FS or select subsequent FS outcomes did not differ between VA or NVA-FS. This suggests that the follow-up care of children with VA-FS does not warrant attention beyond that for NVA-FS.
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente Southern California, USA. Electronic address: sara.y.tartof@kp.org.
authors.forename: Sara Y
authors.initials: SY
authors.lastname: Tartof
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente Southern California, USA. Electronic address: Hung-fu.X.Tseng@kp.org.
authors.forename: Hung Fu
authors.initials: HF
authors.lastname: Tseng
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente Southern California, USA. Electronic address: Amy.L.Liu@kp.org.
authors.forename: In-Lu Amy
authors.initials: IL
authors.lastname: Liu
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente Southern California, USA. Electronic address: Lei.X.Qian@kp.org.
authors.forename: Lei
authors.initials: L
authors.lastname: Qian
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente Southern California, USA. Electronic address: lina.s.sy@kp.org.
authors.forename: Lina S
authors.initials: LS
authors.lastname: Sy
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente Southern California, USA. Electronic address: Rulin.C.Hechter@kp.org.
authors.forename: Rulin C
authors.initials: RC
authors.lastname: Hechter
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente Southern California, USA. Electronic address: smmarcy@labiomed.org.
authors.forename: S Michael
authors.initials: SM
authors.lastname: Marcy
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente Southern California, USA. Electronic address: steven.j.jacobsen@kp.org.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Jacobsen
mesh_terms: D002675:Child, Preschool; D015331:Cohort Studies; D004827:Epilepsy / Q000139:chemically induced / Q000453:epidemiology; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D008297:Male; D016016:Proportional Hazards Models; D012044:Regression Analysis; D012307:Risk Factors; D003294:Seizures, Febrile / Q000139:chemically induced* / Q000453:epidemiology; D014481:United States; D014612:Vaccines / Q000009:adverse effects*
chemical_list: D014612:Vaccines
keywords: Epilepsy; Febrile convulsion; Febrile seizure; Hospitalization; Recurrence; Vaccination