Identifying Associations Among Co-Occurring Medical Conditions in Children With Autism Spectrum Disorders.

Objective: Children with autism spectrum disorder (ASD) have a high prevalence of co-occurring medical conditions, including speech, sleep, and gastrointestinal disorders (constipation and feeding difficulties); developmental delay; attention deficit/hyperactivity disorder; hypotonia; epilepsy; anxiety; disruptive behavior; pica; and eczema. Less is known about whether these commonly coexist in the same children. We sought to determine clinically meaningful, statistically significant associations among co-occurring medical conditions in children with ASD that could lead to better understanding, identification, and treatment of these disorders.

Methods: We studied 2114 children with ASD aged 17 months to 5years and 1221 children aged 6 to 17years at 15 Autism Speaks Autism Treatment Network Registry sites. Clinician-reported diagnoses and problems were grouped into 12 core conditions. We determined the observed prevalence (O) of co-occurring conditions and the estimated expected prevalence (E) across the network, adjusting for sitevariability in the prevalence of individual conditions. Pvalues were calculated using a Cochran-Mantel-Haenszel test stratified by site. We identified pairs of conditions co-occurring more frequently than expected (O/E >1) and less frequently than expected (O/E <1) and highlighted statisticallysignificant differences.

Results: Among the 66 condition pairs for each age group, we confirmed previously identified associations, such as sleep disorders and anxiety symptoms, in older children. We found some associations not previously described, including feeding with sleep disorders (younger children only), constipation with sleep disorders, feeding with speech disorders, and constipation with speech disorders.

Conclusions: We have identified new associations among co-occurring medical conditions in children with ASD, offering the potential to examine common pathways.