title: The epidemiology, risk factors, and impact on hospital mortality of status epilepticus after subdural hematoma in the United States.
abstract: BACKGROUND
  Subdural hematoma (SDH) is a well described risk factor in the development of Status Epilepticus (SE), however the epidemiology of SE after SDH is unknown. In this study, we sought to determine the epidemiology of SE, the prevalence of risk factors, and impact on hospital mortality using a large administrative dataset.
  
  
  METHODS
  Data was derived from the Nationwide Inpatient Sample from 1988 through 2011. We queried the NIS database for patients older than 18 years, with a diagnosis of SDH and SE. Diagnoses were defined by ICD 9 CM codes 432.1, 852.2, 852.3 and 345.3 for SE. Adjusted incidence rates of admission and prevalence proportions were calculated. Multivariate logistic models were then fitted to assess for the impact of status epilepticus on hospital mortality.
  
  
  RESULTS
  Over the 23-year period, we identified more than 1,583,255 admissions with a diagnosis of SDH. The prevalence of SE in this cohort was 0.5% (7,421 admissions). The population adjusted incidence rate of admissions of SDH increased from 13/100,000 in 1988 to 38/100,000 in 2011. The prevalence of SE in SDH, increased from 0.5% in 1988 to 0.7% in 2011. In hospital mortality of patients with SDH and without SE decreased from 17.9% to 10.3% while in hospital mortality of patients with SDH and SE did not statistically change. Mortality increased over the same period (2.3/100,000 in 1988 to 3.9/100.000 in 2011) and the diagnosis of SE increased mortality in this cohort (OR 2.17, p < 0.0001). The risk of SE remained stable throughout the study period, but was higher among older patients, blacks, and in those with respiratory, metabolic, hematological, and renal system dysfunction.
  
  
  CONCLUSIONS
  Our study demonstrates that the incidence of admissions of SDH is increasing in the United States. Despite a decline in the overall SDH related mortality, SE increased the risk of in-hospital death in patients with a primary diagnosis of SDH.
authors: Department of Neurosurgery, Division of Neurocritical Care, University of Texas Health Science Center at San Antonio, Mail Code 7843, 7703 Floyd Curl Drive, Medical School Building 102F, San Antonio, TX 78229-3900 USA.
authors: Ali
authors: A
authors: Seifi
authors: Neurosciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran ; Jefferson Comprehensive Epilepsy Center, Department of Neurology, Thomas Jefferson University, Philadelphia, USA.
authors: Ali Akbar
authors: AA
authors: Asadi-Pooya
authors: Department of Neurosurgery, Division of Neurocritical Care, University of Texas Health Science Center at San Antonio, Mail Code 7843, 7703 Floyd Curl Drive, Medical School Building 102F, San Antonio, TX 78229-3900 USA.
authors: Kevin
authors: K
authors: Carr
authors: The Rothman Institute, Philadelphia, PA USA.
authors: Mitchell
authors: M
authors: Maltenfort
authors: Neurosciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors: Mehrdad
authors: M
authors: Emami
authors: The Rothman Institute, Philadelphia, PA USA.
authors: Rodney
authors: R
authors: Bell
authors: Division of Neuro Critical Care, Capital Institute for Neurosciences, Trenton, USA.
authors: Michael
authors: M
authors: Moussouttas
authors: Department of Neurosurgery, John Muir Medical Center, Walnut Creek, USA.
authors: Moussa
authors: M
authors: Yazbeck
authors: Department of Neurology and Neurosurgery, Thomas Jefferson University, Philadelphia, USA.
authors: Fred
authors: F
authors: Rincon
keywords: Mortality; Risk factors; Status epilepticus; Subdural hematoma