title: The ageing population is neglected in research studies of traumatic brain injury.
abstract: BACKGROUND
  The UK population is ageing with increasing number of elderly patients suffering traumatic brain injury (TBI). The purpose of this study was to identify national TBI admission demographics, analyse the temporal evolution of TBI mortality in a single centre and conduct a systematic review of the literature to identify whether there is an age bias amongst researchers studying TBI.
  
  
  METHODS
  National demographics for TBI were obtained from Health Episode Statistics. TBI patients admitted from 2000 to 2011 to Cambridge University Hospitals Neurocritical Care Unit (NCCU) were divided into age groups (<60, 60-74, ≥75 years). Temporal evolution of mortality was analysed using a logistic regression method. A systematic literature review was conducted to identify primary TBI research studies. Patient's ages were extracted and an average mean age was calculated and compared over time.
  
  
  RESULTS
  From 1998, national TBI admissions have increased with the greatest rise in >60-year age group (p < 0.0001). In a tertiary referral critical care unit (n = 1145), the 60-74 year age group (compared to <60) had a significantly lower improvement in mortality over time (OR: 1.15, 95% CI: 1.02-1.31). A literature review revealed a mean age of 32.73 years (SD ± 12.85) for patients recruited to primary TBI studies.
  
  
  CONCLUSIONS
  Despite increased admissions of elderly patients following TBI and static mortality (single centre, 60-74 year age group) there is little or no evidence of a corresponding increase in the age of patients recruited for TBI studies. In addition to the difficulties this presents in forming evidence-based decisions for the patient with TBI, it may also represent a wider problem for ICU research in an ever-ageing critical care population. More research needs to be conducted to establish the treatment end points for an ageing population.
authors.affiliation: a Neurocritical Care Unit, Cambridge University Hospitals NHS Trust , Cambridge, Cambridgeshire , UK ;
authors.forename: Ben
authors.initials: B
authors.lastname: Gaastra
authors.affiliation: a Neurocritical Care Unit, Cambridge University Hospitals NHS Trust , Cambridge, Cambridgeshire , UK ;
authors.forename: Aisling
authors.initials: A
authors.lastname: Longworth
authors.affiliation: a Neurocritical Care Unit, Cambridge University Hospitals NHS Trust , Cambridge, Cambridgeshire , UK ;
authors.forename: Basil
authors.initials: B
authors.lastname: Matta
authors.affiliation: b Department of Critical Care Medicine , University Hospitals Birmingham NHS Trust , Birmingham , UK.
authors.forename: Catherine
authors.initials: C
authors.lastname: Snelson
authors.affiliation: b Department of Critical Care Medicine , University Hospitals Birmingham NHS Trust , Birmingham , UK.
authors.forename: Tony
authors.initials: T
authors.lastname: Whitehouse
authors.affiliation: b Department of Critical Care Medicine , University Hospitals Birmingham NHS Trust , Birmingham , UK.
authors.forename: Nick
authors.initials: N
authors.lastname: Murphy
authors.affiliation: a Neurocritical Care Unit, Cambridge University Hospitals NHS Trust , Cambridge, Cambridgeshire , UK ;|b Department of Critical Care Medicine , University Hospitals Birmingham NHS Trust , Birmingham , UK.
authors.forename: Tonny
authors.initials: T
authors.lastname: Veenith
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000070642:Brain Injuries, Traumatic / Q000175:diagnosis / Q000401:mortality*; D003422:Critical Care; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D006113:United Kingdom
keywords: Aged; mortality; outcome assessment (health care); traumatic brain injury