title: Epidemiology of Comorbid Conditions Among Adults 50 Years and Older With Traumatic Brain Injury.
abstract: Aging individuals with traumatic brain injury (TBI) experience multiple comorbidities that can affect recovery from injury. The objective of this study was to describe the most commonly co-occurring comorbid conditions among adults 50 years and older with TBI.
  
  
  
  Level I Trauma centers.
  
  
  
  Adults 50 years and older with moderate/severe TBI enrolled in the TBI-Model Systems (TBI-MS) from 2007 to 2014 (n = 2134).
  
  
  
  A TBI-MS prospective cohort study.
  
  
  
  International Classification of Disease-9th Revision codes collapsed into 45 comorbidity categories. Comorbidity prevalence estimates and trend analyses were conducted by age strata (50-54, 55-64, 65-74, 75-84, ≥85 years). A dimension reduction method, Treelet Transform, classified clusters of comorbidities that tended to co-occur.
  
  
  
  The 3 most commonly occurring comorbid categories were hypertensive disease (52.6/100 persons), other diseases of the respiratory system (51.8/100 persons), and fluid component imbalances (43.7/100 persons). Treelet Transform classified 3 clusters of comorbid codes, broadly classified as (1) acute medical diseases/infections, (2) chronic conditions, and (3) substance abuse disorders.
  
  
  
  This study provides valuable insight into comorbid conditions that co-occur among adults 50 years and older with TBI and provides a foundation for future studies to explore how specific comorbidities affect TBI recovery.
authors.affiliation: University of Pittsburgh Department of Physical Medicine and Rehabilitation, Pittsburgh, Pennsylvania (Messrs Kumar and Wang and Drs Juengst, Arenth, and Wagner); University of Pittsburgh Department of Epidemiology, Pittsburgh, Pennsylvania (Messrs Kumar and Wang); Icahn School of Medicine at Mount Sinai, New York, NY (Dr Dams-O'Connor); University of Washington Department of Rehabilitation Medicine, Seattle (Dr Dikmen); Northeastern University Department of Communication Sciences and Disorders, Boston, Massachusetts (Dr O'Neil-Pirozzi); Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, Massachusetts (Dr O'Neil-Pirozzi); Baylor Scott & White Health Medical Center - Plano, TX; Baylor Institute for Rehabilitation, Dallas, TX (Dr Dahdah); Indiana University School of Medicine Department of Physical Medicine and Rehabilitation, Indianapolis, Indiana (Dr Hammond); University of Miami Department of Physical Medicine and Rehabilitation, Miami, Florida (Dr Felix); and University of Pittsburgh Center for Neuroscience, University of Pittsburgh Safar Center for Resuscitation Research, and University of Pittsburgh Department of Neuroscience, Pittsburgh, Pennsylvania (Dr Wagner).
authors.forename: Raj G
authors.initials: RG
authors.lastname: Kumar
authors.forename: Shannon B
authors.initials: SB
authors.lastname: Juengst
authors.forename: Zhensheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Kristen
authors.initials: K
authors.lastname: Dams-OʼConnor
authors.forename: Sureyya S
authors.initials: SS
authors.lastname: Dikmen
authors.forename: Therese M
authors.initials: TM
authors.lastname: OʼNeil-Pirozzi
authors.forename: Marie N
authors.initials: MN
authors.lastname: Dahdah
authors.forename: Flora M
authors.initials: FM
authors.lastname: Hammond
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Felix
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Arenth
authors.forename: Amy K
authors.initials: AK
authors.lastname: Wagner
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000070642:Brain Injuries, Traumatic / Q000150:complications* / Q000453:epidemiology* / Q000523:psychology; D002908:Chronic Disease; D016000:Cluster Analysis; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence