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Comorbidity and outcomes in traumatic brain injury: protocol for a systematic review on functional status and risk of death
  1. Tatyana Mollayeva1,2,3,
  2. Chen Xiong1,2,3,
  3. Sara Hanafy2,3,
  4. Vincy Chan2,3,
  5. Zheng Jing Hu4,
  6. Mitchell Sutton4,
  7. Michael Escobar4,
  8. Angela Colantonio1,2,3,4
  1. 1 Rehabilitation Sciences Institute, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
  2. 2 Research Department, Toronto Rehabilitation Institute-University Health Network, Toronto, Ontario, Canada
  3. 3 Aquired Brain Injury Research Lab, University of Toronto, Toronto, Canada
  4. 4 Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
  1. Correspondence to Dr Tatyana Mollayeva; tatyana.mollayeva{at}


Introduction Reports on the association between comorbidity and functional status and risk of death in patients with traumatic brain injury (TBI) have been inconsistent; it is currently unknown which additional clinical entities (comorbidities) have an adverse influence on the evolution of outcomes across the lifespan of men and women with TBI. The current protocol outlines a strategy for a systematic review of the current evidence examining the impact of comorbidity on functional status and early-term and late-term mortality, taking into account known risk factors of these adverse outcomes (ie, demographic (age and sex) and injury-related characteristics).

Methods and analysis A comprehensive search strategy for TBI prognosis, functional (cognitive and physical) status and mortality studies has been developed in collaboration with a medical information specialist of the large rehabilitation teaching hospital. All peer-reviewed English language studies with longitudinal design in adults with TBI of any severity, published from May 1997 to April 2017, found through Medline, Central, Embase, Scopus, PsycINFO and bibliographies of identified articles, will be considered eligible. Study quality will be assessed using published guidelines.

Ethics and dissemination The authors will publish findings from this review in a peer-reviewed scientific journal(s) and present the results at national and international conferences. This work aims to understand how comorbidity may contribute to adverse outcomes in TBI, to inform risk stratification of patients and guide the management of brain injury acutely and at the chronic stages postinjury on a population level.

PROSPERO registration number CRD42017070033.

  • comorbidity
  • traumatic brain injury
  • prognostic review
  • mortality
  • cognitive/physical status
  • sex and age stratification

This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See:

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  • Contributors Protocol concept and design: TM, AC. Registry PROSPERO: CX. Acquisition of data: TM. Administrative, technical and material support: TM, CX, SH. Statistical analysis approach: TM, VC, ZJH, MS, ME. Drafting of the manuscript: TM. Critical revision of the manuscript for important intellectual content: All authors.

  • Funding The study was funded by the National Institutes of Health (NIH) under Award 1R21 HD08106-01 (principal investigator: Dr Angela Colantonio). AC is supported by the Canadian Institutes for Health Research Grant–Institute for Gender and Health (grant no CGW-126580). TM is supported by the postdoctoral research grant Alzheimer’s Association (AARF-16-442937).

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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