Longitudinal data for autism spectrum disorders (ASD) are limited. The Autism Speaks Autism Treatment Network (ATN) Longitudinal Study tracks behavioral, functional and medical data on youth with ASD to better understand the natural course of ASD and their comorbid symptoms and behaviors.
To describe the trajectory of behavioral, functional, and medical symptoms of ASD over 3-4 years, and the associations across these symptom domains in a large cohort of youth with ASD.
A random sample of subjects originally enrolled in the ATN Registry between 2011-13 were contacted at each of 14 ATN sites to participate in follow-up behavioral and medical assessments on measures collected at baseline enrollment. We report here results from the initial follow-up visit completed in 2015-2016.
Of 1275 subjects contacted, 575 consented to participate. Subjects were 81% male; 81% White, 7% AA, 5% Asian; 92% Non-Hispanic. Age at baseline was 5.9 years ± 3.2 (mean ± SD, range 4.5 to 20.9), and follow-up interval was 3.7 years ± 0.6. There were no differences in sex, race, or ethnicity between consenters & non-consenters. ADOS severity, Vineland Adaptive Behavior Scales (VABS), sleep, GI and seizure disorders were the same in both groups, while non-consenters scored worse on Children’s Sleep Habits Questionnaire (CSHQ), Child Behavior Checklist ADHD scale (CBCL-ADHD), with a trend toward worse scores on the Aberrant Behavior Checklist (ABC) Hyperactivity scale and Pediatric Quality of Life (Peds QL). From baseline to follow-up, the CBCL Total Problems t-scores improved 2.7 points and the ABC Irritability scale improved 2.5 points. Improvements on the CBCL and ABC were greatest for those with higher baseline scores (Figures 1 and 2). Scores on the PedsQL improved 1.8 points over the same interval. Scores on the CSHQ improved a mean of 0.7 points with the greatest improvement seen in those with higher scores at baseline.
While only 45% of targeted subjects completed a follow-up visit, the sample enrolled appears to be largely free of bias and represents one of the largest longitudinal cohorts of youth with ASD reported. The longitudinal changes seen are largely congruent with previous reports in smaller cohorts. Behavioral problems as measured by the CBCL Total Problems scale and the ABC-Irritability scale show modest improvement over the 3-4 year interval. These findings may overestimate long-term trends as the non-consenting group demonstrated slightly worse behavioral problems at baseline. Overall quality of life as measured by the PedsQL and parent reported sleep problems measured by the CSHQ improved minimally on average. Future analyses will examine relationships between measures, changes in medical conditions, and the relationship between medical conditions and behavioral and functional outcomes.