麻豆传媒

Traumatic brain injury (TBI) severity was tied to post-injury attention deficit hyperactivity disorder (ADHD) in children, a systematic review and meta-analysis showed.

Odds for ADHD following severe TBI were higher for both ADHD onset within 1 year (OR 4.81, 95% CrI 1.66-11.03) and diagnosis more than 1 year later (OR 6.70, 95% CrI 2.02-16.82) compared to children with other injuries.

The risks were also higher compared to non-injured controls (OR 2.62, 95% CrI 0.76-6.64, and OR 6.25, 95% CrI 2.06-15.06, respectively).

ADHD itself also may be a risk factor for pediatric TBI, reported Robert Asarnow, PhD, of the University of California Los Angeles, and co-authors in.

"Across TBI injury severity, the rate of pre-injury ADHD diagnoses was 16.0%, which is significantly greater than the general of 10.8% in the most recent Centers for Disease Control and Prevention survey," Asarnow and colleagues wrote. "This result underscores the importance of controlling for pre-injury ADHD in studies attempting to determine the association between TBI and ADHD."

The high rate of pre-injury ADHD in children with TBI also means clinicians should carefully review pre-TBI functioning before initiating treatment, they added.

Across 24 studies and 12,374 children with TBI, severe traumatic brain injuries were associated with increased odds of ADHD compared with 43,192 non-injured children and 299 children with other injuries who served as controls, Asarnow and co-authors found. No relationship between ADHD and concussions and mild or moderate TBI emerged.

A noteworthy point is that mild TBI was not associated with an increased ADHD risk, observed Keith Owen Yeates, PhD, of Alberta Children's Hospital Research Institute in Canada, and co-authors in an .

"This is an important finding given the growing concern about the potential consequences of concussion and mild TBI in children and is consistent with a previous review," the editorialists wrote.

"However, we would caution that not all mild TBIs are alike," they added. "The classification of mild TBI continues to be a topic for debate, but collective variations in acute clinical status, based on factors such as loss of consciousness, Glasgow Coma Scale score, and trauma-related intracranial abnormalities, are demonstrably linked to symptom outcomes after mild TBI."

The meta-analysis looked at three time points: before injury, 1 year or less post-injury, and more than 1 year post-injury. Patients with pre-injury ADHD were included in post-injury analyses in only two studies. In those studies, the researchers subtracted pre-injury ADHD rates from post-injury findings. Studies spanned from 1981 to 2020.

Children included in the analysis were ages 4 to 18 and most were boys (62% of the TBI group, 61% of non-injured controls, and 66% of children with other injuries).

In total, 5,920 children had severe TBI. Of these, 18.8% (95% CrI 9.3%-32.13%) were diagnosed with ADHD within 1 year and 35.5% (95% CrI 20.6%-53.2%) were diagnosed with ADHD more than 1 year later.

While the rate of pre-injury ADHD was higher in children who experienced TBI than in the general population, it was not significantly different from the rate in children with other injuries.

"These results are consistent with evidence that ADHD is a risk factor not only for TBI, but for injury more generally," the editorialists wrote. "An interesting issue for future study with practical implications for prevention is whether an increased risk of injury for children with ADHD arises because of heightened impulsivity or inattention or both."

A limitation of the meta-analysis was the small number of studies and children with other injuries. The 95% credible intervals must be considered when looking at estimated post-injury ADHD rates, the researchers cautioned.

"There are individual exceptions to the aggregate association with injury severity in meta-analyses," Asarnow and co-authors wrote.

"This is particularly relevant to clinical practice," they added. "There may be some patients with mild TBI who present with severe ADHD symptoms and diagnoses, and some patients with severe TBI may not have ADHD symptoms and diagnoses."

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