Injury risk lower when children with ADHD receive medication

By Anne Harding

NEW YORK (Reuters Health) - Children with attention-deficit/hyperactivity disorder (ADHD) are at lower risk of injury when they are on medication, especially brain injury, new findings suggest.

Children and adults with ADHD are known to be at increased risk of injury, including car crashes, fractures, head injuries, burns, and poisoning, Dr. Rafael Mikolajczyk of the Leibniz Institute for Prevention Research and Epidemiology in Bremen, Germany, and colleagues note in their report, published online February 16 in JAMA Pediatrics.

Experimental studies, for example using driving simulators, suggest a lower risk of injury in treated individuals, the researchers add, but results of epidemiologic observational studies have been inconsistent.

Dr. Mikolajczyk and his team used a self-controlled case series design to investigate the association between injury risk and ADHD medication use. Using the German Pharmacoepidemiological Research Database, they identified 37,650 children 3 to 17 years old newly diagnosed with ADHD in 2005 and 2006, who were followed up until 2009. During that time, 2,128 were hospitalized for injury, including 821 children with brain injury.

The investigators identified children who had been prescribed methylphenidate or atomoxetine, and classified them as being on drug treatment for the number of days covered by the prescription. Just over half of the children in the study were prescribed either drug at some point during follow-up; 92% of prescribed doses were for methylphenidate.

The incidence rate ratio for hospitalization for any type of injury was 0.87 while children were on medication, compared to when they were not medicated, which was not a statistically significant difference. However, children were 34% less likely to be hospitalized for brain injury when they were medicated, which was a statistically significant difference.

While the overall injury hospitalization risk reduction didn't reach statistical significance, the authors note, "the point estimates were directed toward a risk reduction."

Drawbacks of the study include the fact that it did not include injuries treated on an outpatient basis, the researchers state, and that their analysis included the number of tablets a child was prescribed, but not the intake recommendation or whether a child actually took the medication.

"Children with ADHD are generally more prone to accidents. This seems to make more of a difference for more severe accidents, including brain injuries as demonstrated in several previous studies," Dr. Mikolajczyk told Reuters Health by email.

"The reduction we observed was in those who received medication at some point," the researcher added. "We cannot infer what would be the effects of medication in those children in our sample who never received medication."

The data source used in the current study wasn't suitable for assessing the risk of less severe injuries, Dr. Mikolajczyk added. "This would be clearly interesting to study."

This research was funded by the Federal Ministry of Education and Research of Germany. Five authors report relationships with pharmaceutical companies; the two other authors report no disclosures.

SOURCE: http://bit.ly/1AOkKhZ

JAMA Pediatr 2015.

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