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Prospectively assessed clinical outcomes in concussive blast vs nonblast traumatic brain injury among evacuated US military personnel.
JAMA Neurol. 2014 Aug; 71(8):994-1002.JN

Abstract

IMPORTANCE

Blast injury has been identified as the signature injury in the conflicts in Iraq and Afghanistan. However it remains to be determined whether fundamental differences may exist between blast-related traumatic brain injury (TBI) and TBI due to other mechanisms.

OBJECTIVES

To determine similarities and differences between clinical outcomes in US military personnel with blast-related vs. non-blast-related concussive TBI and to identify the specific domains of impairment that best correlate with overall disability.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort study involving active duty US Military personnel evacuated from Iraq or Afghanistan to Landstuhl Regional Medical Center, in Landstuhl, Germany. Four groups of participants were enrolled from 2010 to 2013: (1) blast plus impact complex TBI (n=53), (2) non-blast related TBI with injury due to other mechanisms (n=29), (3) blast-exposed controls evacuated for other medical reasons (n=27) (4) non-blast-exposed controls evacuated for other medical reasons (n=69). All patients with TBI met Department of Defense criteria for concussive (mild) TBI. The study participants were evaluated 6-12 months after injury at Washington University in St Louis. In total, 255 subjects were enrolled in the study, and 183 participated in follow-up evaluations, 5 of whom were disqualified.

MAIN OUTCOMES AND MEASURES

In-person clinical examinations included evaluation for overall disability, a standardized neurological exam, headache questionnaires, neuropsychological test battery, combat exposure and alcohol use surveys, and structured interview evaluations for post-traumatic stress disorder (PTSD) and depression.

RESULTS

Global outcomes, headache severity, neuropsychological performance, and surprisingly even PTSD severity and depression were indistinguishable between the two TBI groups, independent of mechanism of injury. Both TBI groups had higher rates of moderate to severe overall disability than the respective control groups: 41/53 (77%) of blast plus impact TBI and 23/29 (79%) of nonblast TBI vs. 16/27 (59%) of blast-exposed controls and 28/69 (41%) of non-blast-exposed controls. In addition, blast-exposed controls had worse headaches and more severe PTSD than non-blast-exposed controls. Self-reported combat exposure intensity was higher in the blast plus impact TBI group than in nonblast TBI group and was higher in blast-exposed controls than in non-blast-exposed controls. However, combat exposure intensity did not correlate with PTSD severity in the TBI groups, but a modest positive correlation was observed in the controls. Overall outcomes were most strongly correlated with depression, headache severity, and number of abnormalities on neuropsychological testing. However a substantial fraction of the variance in overall outcome was not explained by any of the assessed measures.

CONCLUSIONS AND RELEVANCE

One potential interpretation of these results is that TBI itself, independent of injury mechanism and combat exposure intensity, is a primary driver of adverse outcomes. Many other important factors may be as yet unmeasured, and adverse outcomes following war-time injuries are difficult to fully explain.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01313130.

Authors+Show Affiliations

Department of Neurology, Washington University School of Medicine, St Louis, Missouri2Department of Neurological Surgery, University of Washington, Seattle.Department of Neurology, Washington University School of Medicine, St Louis, Missouri.Landstuhl Regional Medical Center, Landstuhl, Germany.Landstuhl Regional Medical Center, Landstuhl, Germany.Landstuhl Regional Medical Center, Landstuhl, Germany.Department of Psychiatry, Washington University School of Medicine, St Louis, Missouri.Department of Neurology, Washington University School of Medicine, St Louis, Missouri.Landstuhl Regional Medical Center, Landstuhl, Germany.Landstuhl Regional Medical Center, Landstuhl, Germany5Department of Trauma, Critical Care, and Acute Care Surgery, Walter Reed National Military Medical Center, Baltimore, Maryland.Landstuhl Regional Medical Center, Landstuhl, Germany6US Air Force Center for Sustainment of Trauma and Readiness Skills, R. Adams Cowley Shock Trauma Center, University of Maryland, Baltimore.Department of Neurology, Washington University School of Medicine, St Louis, Missouri.

Pub Type(s)

Clinical Trial
Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

24934200

Citation

Mac Donald, Christine L., et al. "Prospectively Assessed Clinical Outcomes in Concussive Blast Vs Nonblast Traumatic Brain Injury Among Evacuated US Military Personnel." JAMA Neurology, vol. 71, no. 8, 2014, pp. 994-1002.
Mac Donald CL, Johnson AM, Wierzechowski L, et al. Prospectively assessed clinical outcomes in concussive blast vs nonblast traumatic brain injury among evacuated US military personnel. JAMA Neurol. 2014;71(8):994-1002.
Mac Donald, C. L., Johnson, A. M., Wierzechowski, L., Kassner, E., Stewart, T., Nelson, E. C., Werner, N. J., Zonies, D., Oh, J., Fang, R., & Brody, D. L. (2014). Prospectively assessed clinical outcomes in concussive blast vs nonblast traumatic brain injury among evacuated US military personnel. JAMA Neurology, 71(8), 994-1002. https://doi.org/10.1001/jamaneurol.2014.1114
Mac Donald CL, et al. Prospectively Assessed Clinical Outcomes in Concussive Blast Vs Nonblast Traumatic Brain Injury Among Evacuated US Military Personnel. JAMA Neurol. 2014;71(8):994-1002. PubMed PMID: 24934200.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Prospectively assessed clinical outcomes in concussive blast vs nonblast traumatic brain injury among evacuated US military personnel. AU - Mac Donald,Christine L, AU - Johnson,Ann M, AU - Wierzechowski,Linda, AU - Kassner,Elizabeth, AU - Stewart,Theresa, AU - Nelson,Elliot C, AU - Werner,Nicole J, AU - Zonies,David, AU - Oh,John, AU - Fang,Raymond, AU - Brody,David L, PY - 2014/6/18/entrez PY - 2014/6/18/pubmed PY - 2014/12/30/medline SP - 994 EP - 1002 JF - JAMA neurology JO - JAMA Neurol VL - 71 IS - 8 N2 - IMPORTANCE: Blast injury has been identified as the signature injury in the conflicts in Iraq and Afghanistan. However it remains to be determined whether fundamental differences may exist between blast-related traumatic brain injury (TBI) and TBI due to other mechanisms. OBJECTIVES: To determine similarities and differences between clinical outcomes in US military personnel with blast-related vs. non-blast-related concussive TBI and to identify the specific domains of impairment that best correlate with overall disability. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study involving active duty US Military personnel evacuated from Iraq or Afghanistan to Landstuhl Regional Medical Center, in Landstuhl, Germany. Four groups of participants were enrolled from 2010 to 2013: (1) blast plus impact complex TBI (n=53), (2) non-blast related TBI with injury due to other mechanisms (n=29), (3) blast-exposed controls evacuated for other medical reasons (n=27) (4) non-blast-exposed controls evacuated for other medical reasons (n=69). All patients with TBI met Department of Defense criteria for concussive (mild) TBI. The study participants were evaluated 6-12 months after injury at Washington University in St Louis. In total, 255 subjects were enrolled in the study, and 183 participated in follow-up evaluations, 5 of whom were disqualified. MAIN OUTCOMES AND MEASURES: In-person clinical examinations included evaluation for overall disability, a standardized neurological exam, headache questionnaires, neuropsychological test battery, combat exposure and alcohol use surveys, and structured interview evaluations for post-traumatic stress disorder (PTSD) and depression. RESULTS: Global outcomes, headache severity, neuropsychological performance, and surprisingly even PTSD severity and depression were indistinguishable between the two TBI groups, independent of mechanism of injury. Both TBI groups had higher rates of moderate to severe overall disability than the respective control groups: 41/53 (77%) of blast plus impact TBI and 23/29 (79%) of nonblast TBI vs. 16/27 (59%) of blast-exposed controls and 28/69 (41%) of non-blast-exposed controls. In addition, blast-exposed controls had worse headaches and more severe PTSD than non-blast-exposed controls. Self-reported combat exposure intensity was higher in the blast plus impact TBI group than in nonblast TBI group and was higher in blast-exposed controls than in non-blast-exposed controls. However, combat exposure intensity did not correlate with PTSD severity in the TBI groups, but a modest positive correlation was observed in the controls. Overall outcomes were most strongly correlated with depression, headache severity, and number of abnormalities on neuropsychological testing. However a substantial fraction of the variance in overall outcome was not explained by any of the assessed measures. CONCLUSIONS AND RELEVANCE: One potential interpretation of these results is that TBI itself, independent of injury mechanism and combat exposure intensity, is a primary driver of adverse outcomes. Many other important factors may be as yet unmeasured, and adverse outcomes following war-time injuries are difficult to fully explain. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01313130. SN - 2168-6157 UR - https://www.unboundmedicine.com/medline/citation/24934200/Prospectively_assessed_clinical_outcomes_in_concussive_blast_vs_nonblast_traumatic_brain_injury_among_evacuated_US_military_personnel_ DB - PRIME DP - Unbound Medicine ER -