Effects of Autism Spectrum Disorder Insurance Mandates on the Treated Prevalence of Autism Spectrum Disorder

IMPORTANCE Most states have passed insurance mandates requiring commercial health plans to cover services for children with autism spectrum disorder (ASD). Insurers have expressed concerns that these mandates will increase the number of children diagnosed with ASD (treated prevalence) and therefore increase costs associated with their care. To our knowledge, no published studies have addressed this question. OBJECTIVE To examine whether implementing ASD insurance mandates increases the number of commercially insured children diagnosed with ASD. DESIGN, SETTING, AND PARTICIPANTS A difference-in-differences study was performed using inpatient and outpatient health insurance claims for children 21 years or younger covered by 3 of the largest insurers in the United States-United HealthCare, Aetna, and Humana-from January 1, 2008, through December 31, 2012, made available through the Health Care Cost Institute. Data analysis was conducted from March 15 to August 11, 2015. EXPOSURES Implementation of an ASD insurance mandate in a child's state of residence. MAIN OUTCOMES AND MEASURES The treated prevalence of ASD, measured as a binary indicator of whether a given child in a given calendar month had at least 1 health care service claim associated with a diagnosis of ASD. RESULTS The adjusted treated prevalence among 1 046 850 eligible children (575 299 male [55.0%]) in states with ASD insurance mandates was 1.8 per 1000 and 1.6 per 1000 among children in states without such a mandate (P =.006). The mean increase in treated prevalence attributable to the mandates was 0.21 per 1000 children during the study period (95% CI, 0.11-0.30; P < .001). Mandates in place longer had a larger effect on treated prevalence. The mean increase in treated prevalence of ASD attributable to the mandate was 0.17 per 1000 children (95% CI, 0.09-0.24; P < .001) in the first year following implementation, 0.27 per 1000 children (95% CI, 0.13-0.42; P < .001) in the second year, and 0.29 per 1000 children (95% CI, 0.15-0.42; P < .001) 3 years or more following implementation. CONCLUSIONS AND RELEVANCE Implementing state ASD insurance mandates resulted in increases in the number of children diagnosed with ASD; these numbers increased each year after implementation. Even 3 years or more after implementation, however, treated prevalence of ASD was much lower than community prevalence estimates. This finding may allay concerns that mandates will substantially increase insurance costs, but it suggests that many commercially insured children with ASD remain undiagnosed or are being treated only through publicly funded systems.