Early Clinical Predictors of 5-Year Outcome After Concussive Blast Traumatic Brain Injury

Abstract

The long-term clinical effects of wartime traumatic brain injuries (TBIs), most of which are mild, remain incompletely described. Current medical disability cost estimates from world conflicts continually surpass projections. Additional information regarding long-term functional trajectory is needed to reduce this extensive public health burden.OBJECTIVES To examine 5-year clinical outcomes leveraging existing clinical data collected at 1 year after injury in the same patients and to identify early risk factors for long-term disability. DESIGN, SETTING, AND PARTICIPANTSThis prospective, longitudinal study enrolled active-duty US military after concussive blast injury (n = 50) in the acute to subacute stage and combat-deployed control individuals (n = 44) in Afghanistan or after medical evacuation to Germany from November 1, 2008, through July 1, 2013. One-and 5-year clinical evaluations were completed in the United States. All concussive blast injuries met the Department of Defense definition of mild, uncomplicated TBI. In-person clinical evaluations included standardized evaluations for neurobehavior, neuropsychological performance, and mental health burden that were essentially identical to the evaluations completed at 1-year follow-up. Data were analyzed from October 1 through November 30, 2016. MAIN OUTCOMES AND MEASURESChanges in the in-person standardized evaluations for neurobehavior, neuropsychological performance, and mental health burden from the 1-to 5-year follow-up. Predictive modeling was used to identify early risk factors for long-term disability. RESULTS Among the 94 participants (87 men [93%] and 7 women [7%]; mean [SD] age, 34[8] years), global disability, satisfaction with life, neurobehavioral symptom severity, psychiatric symptom severity, and sleep impairment were significantly worse in patients with concussive blast TBI compared with combat-deployed controls, whereas performance on cognitive measures was no different between groups at the 5-year evaluation. Logistic regression on the dichotomized Extended Glasgow Outcome Scale (GOS-E) at 5 years as a measure of overall disability identified brain injury diagnosis, preinjury intelligence, motor strength, verbal fluency, and neurobehavioral symptom severity at 1 year as risk factors for a poor outcome at 5 years, with an area under the curve of 0.92 indicating excellent prediction strength. Thirty-six of 50 patients with concussive blast TBI (72%) had a decline in the GOS-E from the 1-to 5-year evaluations, in contrast with only 5 of 44 combat-deployed controls (11%). Worsening of symptoms in concussive blast TBI was also observed on measures of posttraumatic stress disorder and depression. Service members with concussive blast TBI experienced evolution, not resolution, of symptoms from the 1-to 5-year outcomes.CONCLUSIONS AND RELEVANCE Considerable decline was observed in military service members with concussive blast TBI when comparing 1-and 5-year clinical outcomes. These results advocate for new treatment strategies to combat the long-te...

Traumatic brain injury: integrated approaches to improve prevention, clinical care, and research

“…107 Furthermore, a decline in outcomes from 1 year to 5 years after injury was recently reported in 36 of 50 (72%) US military service members with concussive blast TBI. 108 Other evidence suggests that TBI is an independent risk factor for stroke. 13 A retrospective case-control study from Taiwan showed that a past history of TBI doubled the risk of stroke (hazard ratio 1•98; 95% CI 1 •86-2•11) and increased post-stroke mortality (odds ratio 1•57; 95% CI 1•13-2•19).…”

Functional Decline 5 Years After Blast Traumatic Brain Injury

“…11 Of importance, much of the empirical literature supporting this conceptualization comes from survivors of moderate or severe TBI, which has been associated with higher rates of disease across multiple body systems 11 and reduced life expectancy compared with the general population. 12 The study by Mac Donald et al 9 provides evidence of deterioration or disease progression but in relatively young individuals exposed to a clinically defined mTBI.…”

Brain and blood biomarkers of tauopathy and neuronal injury in humans and rats with neurobehavioral syndromes following blast exposure

“…In addition to static symptoms that persist, new symptoms may also appear months to years following TBI, including those associated with delayed neurodegeneration and dementia [1,11]. Estimates as to the size of this population vary, but one study of U.S. military service personnel who experienced an mTBI in Iraq or Afghanistan found that-while many improved-about 20% reported the appearance of new symptomatology, such as posttraumatic-stress disorder (PTSD) within 5 years after injury [12,13]. Another study of 188,764 older veterans (mean age of 68 years) revealed that a history of any TBI was associated with a 60% increase in the risk of developing dementia over a 9-year follow up [14][15][16].…”