Quantitative and Qualitative Exploration of Meaningful Change on the Vineland Adaptive Behavior Scales (Vineland™-II) in Children and Adolescents with Autism Without Intellectual Disability Following Participation in a Clinical Trial.

Abstract

The VinelandTM Adaptive Behavior Scale is often used in autism spectrum disorder (ASD) trials. The Adaptive Behavior Composite Score (VABS-ABC) is the standardized overall score (the average of the Socialization, Communication and Daily Living skills domains), and the standardized 2-Domain Composite Score (VABS-2DC) is a novel outcome measure (average of the Socialization and Communication domains). A within-person meaningful change threshold (MCT) has not been established for the VABS-2DC. This paper presents a quantitative and qualitative interpretation of what constitutes a meaningful change in these scores to individuals with ASD without Intellectual Disability (ID; IQ≥70) and their families, as reported by their study partners (SPs). Data were obtained from the aV1ation clinical trial in children and adolescents with ASD and associated exit interviews. The intent-to-treat (ITT) clinical trial population included 308 individuals with autism (85.4% male; average age: 12.4 years [standard deviation (SD)=2.97]); 124 in the child cohort (aged 5 to 12 years; average age: 9.4 years [SD=1.86]), and 184 in the adolescent cohort (aged 13 to 17 years; average age: 14.5 years [SD=1.39]). Study partners of 86 trial participants were included in the Exit Interview Population (EIP): participants represented were 83.7% male, average age: 12.3 years [SD=2.98]). Anchor and distribution-based methods were used to estimate within-person change to support a responder definition, to aid interpretation of the clinical trial data; qualitative data were used to contextualize the meaning of changes observed. A within-person MCT range of 4 to 8 points was proposed for both VABS-ABC and VABS-2DC, which was associated with at least a 1-point improvement on 4 different anchors. Evidence for this within-person MCT was further supported by qualitative data, which suggested any change was considered meaningful to the individual with ASD, as reported by their SP, no matter what the magnitude. A change in standardized score of 4 to 8 points constitutes a within-person MCT on both VABS-ABC and novel VABS-2DC in those with ASD and no ID. A change of this, or more, was reported by the SPs in this trial to be meaningful and highly impactful upon the individuals with ASD and their family.