SAN FRANCISCO – The question of whether stimulant therapy for attention-deficit hyperactivity disorder inhibits a child's growth has long been controversial, with well-designed studies providing conflicting results.
Now, a metaanalysis has indicated that stimulant therapy inhibits both weight gain and expected height gain. Dr. Omar Khwaja reported the results of this metaanalysis in a poster presentation at the annual meeting of the Pediatric Academic Societies.
Twenty-two studies including 2,383 patients were selected for the metaanalysis. The children, aged 0–18 years, were treated with either dextroamphetamine or methylphenidate for a mean duration of 1.5 years.
The metaanalysis included clinical trials, observational cohort studies, and case-control studies.
The effect sizes, as measured by a statistic called Cohen's d, were statistically significant for both weight and height, but greater for weight. However, the metaanalysis found that the effect size favoring weight gain restriction was −0.63, and the effect size favoring restriction in expected height gain was −0.41.
Standard interpretations of the Cohen's d statistic describe an effect size of −0.41 as small to medium, and an effect size of −0.63 as medium to large.
The effect was more pronounced for dextroamphetamine than for methylphenidate, wrote Dr. Khwaja, of Children's Hospital, Boston, and his colleagues.
Their meta-regression analysis evaluated the relative effects of the study's duration, medication type, the study's outcome metric, and the child's age at treatment.
The authors found that medication type proved to be the only statistically significant variable.
“Physicians should continue to be vigilant in monitoring growth parameters in stimulant-treated children,” the authors wrote.