Takayasu arteritis is a rare large vessel vasculitis, a collection of rare conditions of inflamed blood vessels. It predominantly affects the aorta and its main branches. It is associated with significant morbidity and mortality and usually requires corticosteroid and/or long-term immunosuppressive treatment (Kerr, 1994; Maksimowicz‐McKinnon et al., 2007). However, due to the rarity of the condition, the number of people with Takayasu arteritis in England is poorly understood (Onen & Akkoc, 2017).
Our recent meta-analysis showed a global incidence rate of 1 per million person-years, with considerable variation seen between different geographical populations and with females more commonly affected than males (Rutter et al., 2021). A UK study published in 2009 using general practice health records showed a mean prevalence rate of 4.7 per million and an annual incidence of 0.8/million, but only identified 14 people living with the condition nationwide (Watts et al., 2009).
Having a precise estimate of the number of people affected by Takayasu arteritis is vital to improve the care and outcomes for people living with this rare condition. Accurate incidence and prevalence data is important when considering the creation of diagnostic pathways, commissioning of specialised services, funding of high-cost drugs and design of clinical trials. We are particularly interested in how provision for Takayasu arteritis may have changed, or may be required to change, because of the COVID-19 pandemic.
Research hypothesis, aims and questions:
Our aim is to describe the incidence and prevalence of Takayasu arteritis in England using data from Hospital Episode Statistics (HES). We will estimate incidence and prevalence rates for HES years 2006 to 2023 and explore any variation by age, sex, ethnicity, and deprivation.
Specific objectives:
- *Compare Takayasu arteritis-tailored diagnosis date refinement strategies to select the optimal approach.
- Identify cases of Takayasu arteritis in HES Admitted Patient Care (HES APC) episodes and HES Outpatients (OP) and apply the optimised diagnosis date refinement strategy to establish the cohort of people in England receiving at least one TA code between 1997 and 2023.
- Describe the incidence and prevalence of Takayasu arteritis within the cohort overall and by age, sex, ethnicity, deprivation, and region.
- Compare the incidence of Takayasu arteritis before and after the COVID-19 pandemic.
- Explore the completeness of data in HES Outpatients.
- Determine the number of trusts with adequate numbers of TAK cases to gauge feasibility of future clinical trials.
*This bespoke validation work has already been completed anticipating this project in partnership with the National Congenital Anomaly and Rare Disease Registration Service (NCARDRS). It is intended to be submitted for publication as part of this manuscript.
Citation details to follow
- View the analysis code used in NHS England's SDE for England
- View the phenotyping algorithms and codelists used in NHS England's SDE for England
This is a sub-project of project CCU075 approved by the CVD-COVID-UK / COVID-IMPACT Approvals & Oversight Board (sub-project: CCU075_01).
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