Differences among states in the identification of autistic spectrum disorders.

OBJECTIVE To explore variation among the 50 US states in the administrative prevalence of autistic spectrum disorders (ASDs) and factors associated with that variation. DESIGN This survey study used secondary data from all 50 states obtained from the US Department of Education, Washington, DC, and the American Board of Pediatrics, Chapel Hill, NC. MAIN OUTCOME MEASURE The outcome of interest was the proportion of children identified with ASD in the academic year 2000-2001. Linear regression was used to examine its association with education and health system characteristics. RESULTS States ranged in the proportion of children diagnosed with ASD from 0.6 per 1000 to 4.6 per 1000 in 2000-2001. In adjusted analyses, education-related spending, the number of pediatricians in the state, and the number of school-based health centers in the state were positively associated with the administrative prevalence of ASD. CONCLUSIONS Variation in the administrative prevalence of ASD is associated with education-related spending, which may be associated with better-trained educational staff who can recognize the problem, and more and better trained in-school specialists who can provide screening. It is also associated with the availability of health care resources. Increased access to pediatricians and school-based health centers may lead to improved recognition of ASD. Interstate variability in the identification of ASD should be taken into account when interpreting the results of prevalence studies based on administrative data and the associated system characteristics taken into account by policy makers working to improve the recognition of ASD.