Changes in Diagnostic Category among Affected Children in the Interactive Autism Network

Background: In the context of a growing number of children diagnosed with autism spectrum disorders, there is a need to better understand characteristics associated with a first ASD diagnosis, how these characteristics may differ by diagnostic subtype and how they may influence a change in ASD diagnosis.

Objectives: To summarize diagnostic characteristics of IAN Research participants by ASD sub-type and to explore factors associated with a change in ASD diagnosis. 

Methods: As 9/11/07, self-report data on diagnostic and developmental history were collected from 4,675 affected children through an online instrument entitled the Child with an ASD Questionnaire.  Bivariate logistic regression techniques were applied to identify factors associated with a change in ASD diagnosis.  Multiple logistic regression was used to examine the strength of association between these factors and a change in ASD diagnosis after controlling for potential confounders. 

Results: Results of this study show that diagnostic characteristics vary by ASD diagnosis.  In addition, approximately 25% (n=1,138) of all ASD children in IAN Research have a current diagnosis that differs from their first.   These children are significantly less likely than their ASD peers to have a first ASD diagnosis of autism or Asperger’s syndrome (OR 0.1, 95%CI 0.02-0.45 for autism, OR 0.09, 95%CI 0.02-0.43 for Asperger’s syndrome).  Furthermore, children whose ASD diagnosis changes are less likely to have been diagnosed by a clinical psychologist or a team of health professionals (OR 0.71, 95%CI 0.54-0.94, OR 0.59, 95%CI 0.44-0.80).  These relationships remain statistically significant after controlling for current age, gender, race and other factors. 

Conclusions: A change in ASD diagnosis among IAN participants is not uncommon.  Findings from this study are of particular clinical and public health significance as they suggest that a change in ASD diagnosis depends upon both the symptomatology of the child and the context in which he/she is diagnosed.