title: Why U.S. epilepsy hospital stays rose in 2006.
abstract: OBJECTIVE
  We observed a substantial increase in age-adjusted hospitalization rates in the United States National Hospital Discharge Survey data from 1996 to 2010. We aimed to assess reasons for this increase.
  
  
  METHODS
  The National Hospital Discharge Survey collected data on a national sample of short-term hospital stays in nonfederal hospitals. We determined epilepsy-related discharge diagnoses by age, gender, and region using weighted analysis, and estimated age-adjusted rates and annual percent changes using regression analysis. We also looked at epilepsy as the principal discharge diagnosis in the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project.
  
  
  RESULTS
  In the United States, on average, nearly 110,000 more admissions were reported each year with epilepsy as the principal discharge diagnosis in 2006-2010 than in 1996-2005, a 2.7-fold increase in hospitalization rates from epilepsy. During this period, there were more hospitalizations with principal discharge diagnosis of epilepsy not otherwise specified, and among older patients. The number of discharges with seizure not otherwise specified dropped dramatically after 2006, and was more evident among pediatric patients. The age-adjusted rates of hospital stays combining discharges with any mention of epilepsy (345.XX) or seizures unspecified (780.39) in seven discharge diagnoses, were similar in 1996-2005 and 2006-2010.
  
  
  CONCLUSIONS
  We postulate that the excess in hospitalizations with epilepsy as first discharge diagnosis in 2006-2010 in the United States was related to the changes in coding in 2006. Any use of U.S. hospital discharge data with epilepsy-related diagnosis after that date will require further validation. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.
authors.affiliation: Department of Epidemiology, College of Public Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas, U.S.A.
authors.forename: Víctor M
authors.initials: VM
authors.lastname: Cárdenas
authors.forename: Gustavo C
authors.initials: GC
authors.lastname: Román
authors.forename: Adriana
authors.initials: A
authors.lastname: Pérez
authors.forename: W Allen
authors.initials: WA
authors.lastname: Hauser
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004827:Epilepsy / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy*; D005260:Female; D019538:Health Care Surveys; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010351:Patient Discharge / Q000706:statistics & numerical data; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: Coding; Epilepsy; Hospitalization; Surveillance; Trends