Designing and recruiting to UK autism spectrum disorder research databases: do they include representative children with valid ASD diagnoses?

OBJECTIVES: (1) Describe how the Autism Spectrum Database-UK (ASD-UK) was established; (2) investigate the representativeness of the first 1000 children and families who participated, compared to those who chose not to; (3) investigate the reliability of the parent-reported Autism Spectrum Disorder (ASD) diagnoses, and present evidence about the validity of diagnoses, that is, whether children recruited actually have an ASD; (4) present evidence about the representativeness of the ASD-UK children and families, by comparing their characteristics with the first 1000 children and families from the regional Database of children with ASD living in the North East (Dasl(n)e), and children and families identified from epidemiological studies. SETTING: Recruitment through a network of 50 UK child health teams and self-referral. PATIENTS: Parents/carers with a child with ASD, aged 2-16 years, completed questionnaires about ASD and some gave professionals' reports about their children. RESULTS: 1000 families registered with ASD-UK in 30 months. Children of families who participated, and of the 208 who chose not to, were found to be very similar on: gender ratio, year of birth, ASD diagnosis and social deprivation score. The reliability of parent-reported ASD diagnoses of children was very high when compared with clinical reports (over 96%); no database child without ASD was identified. A comparison of gender, ASD diagnosis, age at diagnosis, school placement, learning disability, and deprivation score of children and families from ASD-UK with 1084 children and families from Dasl(n)e, and families from population studies, showed that ASD-UK families are representative of families of children with ASD overall. CONCLUSIONS: ASD-UK includes families providing parent-reported data about their child and family, who appear to be broadly representative of UK children with ASD. Families continue to join the databases and more than 3000 families can now be contacted by researchers about UK autism research.