The aim of this study is to investigate the burden of juvenile idiopathic arthritis (JIA) in the UK. JIA is the umbrella term for several subtypes of arthritis that develop in children and young people (CYP) under the age of 16. Despite onset in childhood, it is a chronic disease and will continue into adulthood for significant number of CYP. Currently, we do not know how often this disease occurs in the UK, or how often it persists into adulthood. This may in part be due to variations in the way the disease has been defined in the past, making previous estimates unreliable. Reliable estimates are, however, crucial to plan health services and allocate resources, particularly in a disease such as JIA, where high-cost drugs are a mainstay of treatment.
The first objective of this study, therefore, is to use a national dataset of primary care records to provide up-to-date estimates of disease occurrence in CYP and the number who continue to have active arthritis through adolescence into adulthood. In addition, JIA is known to be associated with other illnesses such as eye disease, infections, cancer and even early death, which contribute to the overall burden of the disease. Therefore, this study will also investigate how common these outcomes are compared to a control population of healthy CYP. Finally, we will investigate how much CYP with JIA use the NHS by measuring the frequency of primary care visits and hospital attendances, again compared to a healthy control cohort.
This study aims to establish the overall burden of juvenile idiopathic arthritis (JIA) in the UK. The primary aim is to report the incidence, prevalence and persistence of JIA into adulthood. Secondary objectives will investigate associations between JIA and mortality, comorbidities and healthcare utilisation.
JIA is an umbrella term for subtypes of inflammatory arthritis diagnosed prior to age 16. Classification criteria have changed over time; consequently, incidence and prevalence rates vary significantly. The only UK estimates come from 1996, prior to international consensus on classification and are therefore outdated. With the emergence of high cost drugs to treat JIA, accurate estimates are essential for appropriate health service planning and resource allocation. Alongside this, accurate data JIA disease burden are urgently required, including mortality risk, occurrence of important comorbidities such as uveitis, cancer and infections, and healthcare utilisation.
Cases of JIA will be identified using Read codes. Annual incidence and prevalence rates will be estimated along with standardised mortality ratios. Poisson regression will be used to determine incidence rates stratified by age, gender, subtype, socioeconomic status and region of the UK, and rates of healthcare utilisation compared to a matched healthy control cohort. In a subset hospital episodes statistics data will be used to validate the JIA case definition and to identify the proportion of young people with JIA that go on to use adult rheumatology services. The risk of mortality and comorbidities in patients with JIA compared to controls will be assessed using multivariable Cox proportional hazards regression model.
Occurrence of JIA
- All-cause mortality
- Hospital admission for uveitis
- Hospital admission for infection
- Hospital admission for cancer.
- Pregnancy and birth rates for mothers with JIA and neonatal morbidity in their children.
Jenny Humphreys - Chief Investigator - University of Manchester
Ruth Costello - Corresponding Applicant - University of Manchester
Janet McDonagh - Collaborator - University of Manchester
Kimme Hyrich - Collaborator - University of Manchester
Lianne Kearsley-Fleet - Collaborator - University of Manchester
Mark Lunt - Collaborator - University of Manchester
Max Lyon - Collaborator - University of Manchester
Richard Beesley - Collaborator - University of Manchester
William Dixon - Collaborator - University of Manchester
Yvonne Tan - Collaborator - University of Manchester
2011 Rural-Urban Classification at LSOA level;CPRD Mother-Baby Link;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation;Pregnancy Register