Autism spectrum disorder (ASD) encompasses neurodevelopmental disorders that affect social function and communication. Symptoms such as delayed speech development, limited interaction with others, avoidance of eye contact and repetitive behaviour movements, are typically identified in childhood.
There is limited understanding of how the diagnosis rates vary among children of different ages, and if the rates have changed over time, especially with updates in diagnostic criteria for ASD over the last decade. This information would help provide insight for service planning and provisions.
This study aims to describe the proportion of children aged 1 to 18 years that have been diagnosed with autism spectrum disorder (ASD). We will look back over the last 15 years of patient records and describe the proportion diagnosed each year, to see if this has varied over time. We will also look at the diagnosis rates among age groups in each calendar year.
There may also be regional variation in diagnosis rates for ASD (for example due to access to services and other factors). We will look at the proportion of children diagnosed with ASD at each GP site, and will describe the variation. We will also report on key factors that may be associated with this, such as ethnicity and deprivation.
There is a paucity of published evidence on the incidence of ASD in children in the UK. Reliable evidence is needed to help provide insight for service planning and provisions.
This study aims to describe the incidence of ASD in children aged 1 to 18 years, and the determinants of variation in diagnosis rates among GP clinics. The study will be an exploratory retrospective cohort study using the most recent 15 years of linked electronic medical records from the UK.
ASD diagnosis will be identified as any record of autism, Aspergers syndrome or pervasive developmental disorder using an apriori list of Readcodes that have previously been validated and published by Hagberg et al (2017). A patients earliest record of ASD will be their incident diagnosis.
For the primary analysis, annual incidence rates of ASD will be reported to observe if there have been changes in recent years. The incidence at each calendar year will also be stratified by age groups. Incidence rates of ASD by GP site will be analysed to report on variation (after adjusting for patient characteristics).
Key determinants of variation in rates among GP clinics, such as ethnicity and SES, will also be reported to provide insight on potential equitable or inequitable access to services.
In a secondary analysis, we will repeat the primary analysis but this time using autism Readcodes only as the outcome (not using Aspergers syndrome and pervasive developmental disorder).
In sensitivity analyses, we will review patients with discrepant ethnicity data who have initially been classified in one ethnic group, and will move them to their other ethnic group, and repeat the primary analysis. We will also repeat the main analysis (which will use Gold and Aurum combined) but this time analysing Gold and Aurum separately.
The primary outcome is diagnosis of ASD. ASD diagnosis will be identified as any record of autism, Aspergers syndrome or pervasive developmental disorder, using an apriori list of Readcodes. A patients earliest record of ASD will be their incident diagnosis.
As defined The list of ASD Readcodes have been previously validated and published by Hagberg et al (2017).,ASD will be a composite binary outcome of Autism, Aspergers syndrome and Pervasive developmental disorder. The following codes will be used,
readcode meddesc
Autism
E140.00 Infantile autism
E140000 Active infantile autism
E140100 Residual infantile autism
E140.12 Autism
E140.13 Childhood autism
E140z00 Infantile autism NOS
Eu84000 [X]Childhood autism
Eu84012 [X]Infantile autism
Eu84100 [X]Atypical autism
Eu84z11 [X]Autistic spectrum disorder
Eu84011 [X]Autistic disorder
Aspergers syndrome
Eu84500 [X]Asperger's syndrome
Pervasive developmental disorder
Eu84.00 [X]Pervasive developmental disorders
Eu84y00 [X]Other pervasive developmental disorders
Eu84z00 [X]Pervasive developmental disorder, unspecified
Amit Kiran - Chief Investigator - Astellas Pharma Europe Ltd. - UK
Amit Kiran - Corresponding Applicant - Astellas Pharma Europe Ltd. - UK
HES Admitted Patient Care;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation