ATN Longitudinal Study: 3-Year Follow-up of 575 Youth with ASD

Background:  This abstract introduces the ATN Longitudinal Study, a large-scale effort to describe behavioral, functional, and medical outcomes in children and adolescents with ASD. Comprehensive longitudinal data for youth with ASD are extremely limited, and few large-scale longitudinal cohorts exist. The Autism Speaks Autism Treatment Network (ATN) is a collaboration between Autism Speaks and 14 children’s hospitals and medical institutions across North America. The ATN has established an open-access registry of data from almost 7000 youth with ASD, containing diagnostic, behavioral, functional, and medical data, and biospecimens in a limited subset. The ATN Longitudinal Study was designed to collect data 3-4 years after initial enrollment in the ATN Registry in a cohort that is broadly representative of the ATN Registry participants.

Objectives:

To describe the trajectory of behavioral, functional, and medical symptoms of ASD over 3-4 years, and the associations across these symptom domains.

Methods:

Subjects were randomly selected from among those who enrolled in the ATN Registry in 2011-13. These families were re-contacted for follow-up assessment on a battery of measures that were administered at enrollment, including the Vineland-II, CBCL, Aberrant Behavior Checklist, Pediatric Quality of Life scale (PedsQL), Children’s Sleep Habits Questionnaire (CSHQ), a standardized medical history form, and limited physical examination. Families who were not able to schedule an in-person assessment were evaluated remotely by phone, internet, and mail. In this first abstract, we report on functional outcomes from the Vineland.

Results:

1275 subjects were contacted, and 575 consented to participate. Consented subjects were 83% male; 81% White, 7% AA, 5% Asian, and 92% non-Hispanic. Age was 5.9 years ± 3.2 (mean ± SD, range 2y0m to 16y10m) at initial assessment, and 9.7 ± 3.2 at follow-up. Consenters and non-consenters showed no differences in race, ethnicity, or sex and had similar baseline scores for ADOS severity, Vineland-II, and frequency of sleep, GI and seizure disorders. Non-consenters scored worse on measures of hyperactivity, on the CSHQ, and had trend worse scores on the PedsQL.

Among 571 participants who completed follow-up Vineland-II assessments, Composite scores showed little change: 71.6 ± 11.6 at baseline, and 70.5 ± 14.6 at follow-up. Domain scores also showed little change in the full cohort. However, while the mean Composite and Domain scores were steady or showed small increases among subjects <6 y.o. at baseline, they tended to decrease among those who were 6-12 y.o. at baseline (Figure 1). Among subjects whose baseline Composite scores were <80, mean scores were steady or increased slightly, but among those whose baseline scores were >=80, scores decreased (Figure 2).

Conclusions:

Mean changes in Vineland score seen among participants in the ATN Longitudinal Study were largely congruent with previous reports in smaller cohorts. Future analyses will examine the relationships between the Vineland and other measures and the association of medical co-morbidities and these outcomes in our ongoing study.