The co-morbidity burden of children and young adults with autism spectrum disorders

Abstract

Objectives: Use electronic health records Autism Spectrum Disorder (ASD) to assess the comorbidity burden of ASD in children and young adults.

Study design: A retrospective prevalence study was performed using a distributed query system across three general hospitals and one pediatric hospital. Over 14,000 individuals under age 35 with ASD were characterized by their co-morbidities and conversely, the prevalence of ASD within these comorbidities was measured. The comorbidity prevalence of the younger (Age<18 years) and older (Age 18-34 years) individuals with ASD was compared.

Results: 19.44% of ASD patients had epilepsy as compared to 2.19% in the overall hospital population (95% confidence interval for difference in percentages 13.58-14.69%), 2.43% of ASD with schizophrenia vs. 0.24% in the hospital population (95% CI 1.89-2.39%), inflammatory bowel disease (IBD) 0.83% vs. 0.54% (95% CI 0.13-0.43%), bowel disorders (without IBD) 11.74% vs. 4.5% (95% CI 5.72-6.68%), CNS/cranial anomalies 12.45% vs. 1.19% (95% CI 9.41-10.38%), diabetes mellitus type I (DM1) 0.79% vs. 0.34% (95% CI 0.3-0.6%), muscular dystrophy 0.47% vs 0.05% (95% CI 0.26-0.49%), sleep disorders 1.12% vs. 0.14% (95% CI 0.79-1.14%). Autoimmune disorders (excluding DM1 and IBD) were not significantly different at 0.67% vs. 0.68% (95% CI -0.14-0.13%). Three of the studied comorbidities increased significantly when comparing ages 0-17 vs 18-34 with p<0.001: Schizophrenia (1.43% vs. 8.76%), diabetes mellitus type I (0.67% vs. 2.08%), IBD (0.68% vs. 1.99%) whereas sleeping disorders, bowel disorders (without IBD) and epilepsy did not change significantly.

Conclusions: The comorbidities of ASD encompass disease states that are significantly overrepresented in ASD with respect to even the patient populations of tertiary health centers. This burden of comorbidities goes well beyond those routinely managed in developmental medicine centers and requires broad multidisciplinary management that payors and providers will have to plan for.

Figure 1. Prevalence of co-morbidities of autism and prevalence of autism in these comorbidities.

Shown here is the prevalence of co-morbidities for individuals with autism (denoted as p(Dx}Autism) where Dx is the co-morbidity) and the reciprocal prevalence of autism given the co-morbidity (i.e. p(Autism|Dx)). The prevalence is reported for patients younger than 35 years old. These results are consistent with prior studies and also reinforce that monogenic disorders associated with autism individually only account for a small fraction of the disorder. It also reinforces that autism is present in over 5% of the individuals evaluated for CNS anomalies, epilepsy, muscular dystrophy, schizophrenia, Fragile X Syndrome and Tuberous Sclerosis.

Figure 2. Comorbidities in autism vs same morbidities in the general hospital population.

All co-morbities have a significantly different proportion in the ASD population (p<0.0001 by Chi-square) except for the autoimmune diseases (from which IBD and DM1 were excluded and are shown separately on the chart) for which p<0.5. Several of the disorders (epilepsy, muscular dystrophy, schizophrenia, sleep disorders and CNS anomalies have approximately an order of magnitude increased prevalence).

Figure 3. Comorbidities of ASD in younger (0–17 years) vs older (18–34 years).

All the comorbidities' prevalence were significantly different (p<0.0001 by Chi square) except for bowel disorders, epilepsy, autoimmune disorders (excluding IBD and DM1) and sleep disorders.