Using phecode analysis to characterize co-occurring medical conditions in autism spectrum disorder

Individuals with autism spectrum disorders (ASD) experience a significant number of co-occurring medical conditions, yet little is known about these conditions beyond prevalence. We hypothesized that individuals with ASD experienced an increased burden of co-occurring conditions as measured by presence, frequency, and duration of visits related to co-occurring conditions. We expected that age of ASD diagnosis (early, <7; late, >7) would be associated with different co-occurring conditions. Medical record data were extracted from a large anonymized medical center database for 3097 individuals with ASD and 3097 matched controls. Co-occurring conditions were characterized using a novel tool (pyPheWAS) to examine presence, frequency, and duration of each condition. We identified several categories of co-occurring conditions in ASD: neurological (epilepsy, sleep disorders); psychiatric (mood disorders, adjustment/conduct disorders, suicidal ideation), and developmental. Early ASD diagnosis was associated with epilepsy-related conditions, whereas a later diagnosis was associated with psychiatric conditions. The early ASD diagnosis group had later first diagnosis of co-occurring psychiatric conditions compared to the late ASD diagnosis group. Our work confirms individuals with ASD are under a significant medical burden, with increased duration and frequency of visits associated with co-occurring conditions. Adequate management of these conditions could reduce burden on individuals with ASD.