Medical Comorbidities in Autistic Children: Prevalence, Sex-Specific Clustering, and Network Patterns at Diagnosis in a Chilean Clinical Cohort

Purpose : Autistic children frequently present with medical comorbidities that complicate clinical care, yet patterns of co-occurrence at diagnosis—particularly in underrepresented regions—remain insufficiently described. This study examined the prevalence, distribution, and sex-specific clustering of medical comorbidities in a large Chilean ASD cohort. Methods : We conducted a retrospective chart review of 544 children diagnosed with autism spectrum disorder (ASD) between 2015 and 2023 at a specialized pediatric center. Comorbidities were identified using a standardized caregiver interview, supplemented by physical and neurological examinations, anthropometric measurements, and medical record review. Analyses included prevalence estimates, temporal trends, and sex-stratified exploratory network analysis. Results : At least one comorbidity was present in 90% of children. The most frequent were insomnia (61%), overnutrition (52%), allergic rhinitis/atopic dermatitis (28%), and constipation (27%). Undernutrition declined significantly over time (8% to 2%; p = 0.028), while other conditions remained stable. Network analysis showed denser co-occurrence in boys—particularly insomnia, overnutrition, and constipation—whereas in girls, allergic disorders more often clustered with undernutrition. No significant demographic differences were found between children with and without comorbidities. Conclusion : Medical comorbidities are highly prevalent in autistic children at diagnosis, with distinct sex-specific co-occurrence patterns that may guide early screening priorities. These findings support systematic, multidisciplinary assessment at diagnosis and underscore the need for prospective studies to validate these patterns and explore their determinants.