Background/Aims Diagnoses of Autism Spectrum Disorders (ASDs) continue to rise, yet few effectiveness studies of autism treatments exist. The major limitations to conducting such studies include locating, characterizing, and enrolling sufficiently large and representative ASD patient samples. This project has created a large, comprehensive, and dynamic ASD registry across five integrated not-for-profit health systems participating in the NIMH Mental Health Research Network (MHRN). This registry will enable rapid identification and enrollment of patients into large-scale studies investigating treatment interventions as well as pharmacogenomic and etiologic hypotheses.

Methods Nine study sites compose the MHRN, which serve a diverse population of 10 million people in 11 states. The ASD registry is based in five MHRN sites: Kaiser Permanente (KP) Northern California, KP Southern California, KP Northwest, KP Georgia, and Harvard Pilgrim Health Plan. ASD registry investigators developed algorithms which identify children with ASD from electronic medical records and health claims data. ASD diagnoses are validated using structured record review and expert review. Diagnostic and demographic data recorded in health plan electronic databases from 1995–2010 on all 0–17 year olds who were health plan members as of December 2010 were used to describe ASD prevalence in this population.

Results Overall prevalence of ASD was 1.2% (23,811/2,049,442), and ranged from 0.86% (458/53,297) to 1.6% (3,425/212,375) across all sites. Most ASD cases were 10–14 years old (36% (8,165/22,606), range: 35% (2,717/7,775) – 41% (617/1,515)) or 5–9 (35% (7,848/22,606), range: 30% (459/1,515) – 37% (161/432)). Fewer cases were 15–17 years old (18% (4,064/22,606), range: 16% (1,578/9,641) – 22% (329/1,515)) or 0–4 years old (11% (2,529/22,606), range: 7% (110/1,515) – 12% (1,159/9,641)). The overall ratio of male to female cases was 4.29 (range: 3.71–5.11). Of children diagnosed with an ASD, 59% were diagnosed with Autistic Disorder ((14,061/23,811), range: 33% (1,131/3,425) – 71% (7,154/10,068)).

Discussion Demographic diversity and extensive electronic health records make this registry an ideal environment for studying ASDs. Future aims include investigating use of services not provided by HMOs, collection of genetic material from individuals and families with ASD’s, and harmonization of data from many sources such as birth certificates and census data.