Gastrointestinal Symptom Trends in Children with Autism Spectrum Disorder: A Retrospective Analysis

Gastrointestinal Symptom Trends in Children with Autism Spectrum Disorder: A Retrospective Analysis

Introduction: Gastrointestinal (GI) symptoms are reported to be highly prevalent in children with autism spectrum disorder (ASD), with some estimates of general symptom prevalence reaching as high as 96.8% [1]. According to one meta-analysis, the odds of experiencing a GI symptom were 4.4 times higher in children with ASD compared to the typically developing population [2], representing a significant disparity in the rates at which these groups are affected. Although many studies have investigated the prevalence of GI symptoms that co-occur with ASD, few have considered how the appearance and/or diagnosis of these symptoms might change throughout early childhood. Knowledge of such patterns would help illuminate potential trends in the progression/regression of ASD and associated co-occurring conditions in affected children.

Materials and Methods: This study involves a retrospective analysis of claims data from the OptumLabs® Data Warehouse, which includes de-identified claims data for privately insured and Medicare Advantage enrollees in a large, private, U.S. health plan. The database contains longitudinal health information on enrollees, representing a diverse mixture of ages, ethnicities, and geographical regions across the United States. The health plan provides comprehensive full insurance coverage for physician, hospital, and prescription drug services [3]. Data for children born between 2000 and 2010 with at least five years of continuous coverage enrollment beyond their initial date of enrollment (index date) were used in this study. Children with ASD were identified as those having at least two diagnosis claims on separate dates for autistic disorder, Asperger syndrome, or a pervasive developmental disorder not otherwise specified, without any claims for Rett syndrome or childhood disintegrative disorder [4], after two years of age. The control group consisted of children without claims for any of the aforementioned diagnoses after two years of age. This study was exempt from Institutional Review Board approval since all data were pre-existing and de-identified.

Results and Discussion: We identified 3200 children with ASD and 275339 control children meeting all inclusion criteria making this one of the largest studies of its kind. Claims for symptoms of the lower GI tract (constipation, diarrhea, abdominal pain, noninfectious gastroenteritis/colitis) were tracked over the span of the five-year enrollment period. Figure 1 shows the percentage of members in each cohort having any of these GI claims during each three-month interval of the total enrollment period. While the percentages of children diagnosed with ASD with GI claims are higher throughout the entire five year period, there is nevertheless a clear temporal trend that can be observed. The percentages for the control group steadily decline after the first year, whereas the numbers stay relatively constant for the groups with ASD after the first three months. During the last two years of this five year period, 37.1% of the ASD cohort had a GI complaint compared to only 20.1% of controls (odds ratio = 2.35; 95% confidence interval = 2.28, 2.42). This estimate of GI symptom prevalence in children with ASD is exceptionally consistent with a recent meta-analysis that found the median reported prevalence of general GI symptoms among studies using medical records or claims data to be 37% [5].

Conclusions: The temporal trends in GI symptom prevalence in children with and without ASD diverge over time, hinting at temporal factors contributing to the onset of these co-occurring conditions. A robust cohort of children has been identified that can be used to further investigate these factors in future studies.

References: [1] Babinská K, Physiol Res 2014, 63: S613-8. [2] McElhanon BO, Pediatrics 2014, 133(5): 872-83. [3] OptumLabs, OptumLabs and OptumLabs Data Warehouse (OLDW) Descriptions and Citation, Cambridge, MA: n.p., February 2018. PDF. Reproduced with permission from OptumLabs. [4] Burke JP, Autism 2013, 18(3): 321-30. [5] Holingue C, Autism Res 2018, 11(1): 24-36.