Prevalence of Autism Spectrum Disorders in Medicaid and associated health care utilization

Purpose: The CDC recently found, on average, one case of an autism spectrum disorder (ASDs) per 150 children in 2002. This current study examines this topic within the context of Medicaid, the largest health care payer of children with special health care needs, especially autism. Never before have prevalence rates of autism in Medicaid been published for all states.

Methods: This study used the 2002 Medicaid Analytic eXtract (MAX) database of Medicaid claims and person-level eligibility information constructed by and housed at the Centers for Medicare and Medicaid Services (CMS). All outpatient, inpatient and long term care claims with an ICD-9-cm diagnosis code indicating autism, pervasive developmental disorder-not otherwise specified and/or Asperger's disorder were flagged as ASD and were distilled to unduplicated patient level data.

Results: This study found 69,126 Medicaid enrollees with an ASD in 2002. Seventy eight percent of those with ASD were male. The majority (55.9 percent) were Caucasian, while 16.4% were African American and 6.6% were Hispanic or Latino. Race category was unknown for a full 17.2% of ASD Medicaid enrollees. Smaller percentages of less than one or two percent comprised the remaining racial groups. The age distribution was positively skewed with 23.46% of ASD Medicaid enrollees being adults greater than 21. Rates will be presented by state, by key demographic factors and by managed care versus fee-for-service.

Implications: This study provides the essential groundwork for the nexus of politics, policy and public health as it relates to the understanding and funding of autism health care.