SAN FRANCISCO – Seven percent of 110 children with autism spectrum disorders had iron depletion before starting antipsychotics for aggression, and rapid weight gain on antipsychotics was associated with further decreases in iron levels.
Eleven percent of 79 children with follow-up data after a mean of 18 months of antipsychotic treatment had low plasma ferritin levels (less than 12 ng/mL). Mean plasma ferritin concentrations in the cohort as a whole decreased from 26 ng/mL at baseline to 17 ng/mL, Dr. Nicole S. Del Castillo reported in a poster presentation at the annual meeting of the American Academy of Child and Adolescent Psychiatry.
The mean body mass index (BMI) was 18 kg/m2 at baseline and 20 kg/m2 after 18 months. The percent increase in BMI was significantly and negatively associated with the decrease in ferritin concentration, change in ferritin, and percent change in ferritin after adjustment for the effects of other factors, reported Dr. Del Castillo, a psychiatry fellow at the University of Iowa, Iowa City.
Dr. Nicole S. del Castillo
The investigators adjusted for the effects of age, sex, and the time between baseline and follow-up BMI measurements.
Children with autism spectrum disorders already are at increased risk of iron deficiency, previous studies have shown. Other studies report that two second-generation antipsychotics that are approved to treat aggression associated with autism spectrum disorders – risperidone and aripiprazole – cause significant weight gain, especially in youth. Rapid weight gain can lead to iron deficiency in children when iron absorption is unable to keep pace with the need to form red blood cells to vascularize newly formed tissue, Dr. Del Castillo explained.
Clinicians should consider closely monitoring iron status in children with autism spectrum disorders who are treated with second-generation antipsychotics, especially if they gain substantial weight, she suggested. "Not only test for lipids and glucose, but also look at iron deficiency," which is a potentially treatable problem, she said.
The study analyzed data obtained from a Research Units on Pediatric Psychopharmacology trial in which children with autism spectrum disorders and serious behavior problems were randomized to treatment with risperidone alone or risperidone plus behavior management training for parents. Patients in the current sample averaged 8 years in age. Primary diagnoses included autism in 62%, pervasive developmental disorder not otherwise specified in 32%, and Asperger’s syndrome in 6%.
No significant associations were seen between baseline ferritin concentrations and age, baseline BMI, baseline or follow-up scores on the Aberrant Behavior Checklist, or percent change in ferritin concentration.
Dr. Del Castillo reported having no relevant financial disclosures. Some of her coinvestigators reported relationships with several pharmaceutical companies, including , Eli Lilly, Shire, AstraZeneca, Novartis, Forest Research, and Hoffmann-LaRoche.