Incidence and prevalence of Takayasu arteritis in England before and after the COVID-19 pandemic: results from RECORDER.

Objectives: Takayasu arteritis (TAK) is a rare large vessel vasculitis associated with substantial morbidity and mortality. Evidence on its epidemiology, including the COVID-19 pandemic's impacts, is incomplete. We aimed to describe the incidence and prevalence of TAK in England using national routinely collected healthcare data. Methods: Using Hospital Episode Statistics for the whole of England (Admitted Patient Care and Outpatients), we identified all people with the International Classification of Diseases, 10th revision code for TAK. We validated our case ascertainment and diagnosis date refinement strategies in five National Health Service Trusts and using the unique Imperial College TAK cohort of 123 confirmed cases. We calculated the incidence of TAK in England from 2006 to 2023 (cohort design), particularly focusing on the COVID-19 pandemic, and point prevalence for 1 July 2022 (cross-sectional design). Results were reported by key demographic variables. Results: The incidence of TAK in England was 1.3 (95% CI 1.3, 1.4) per million per year and was stable except for a 30% decrease in 2020-2021 (COVID-19 pandemic). The prevalence of TAK in mid-2022 was 22.5 per million (95% CI 21.3, 23.8). The median age at diagnosis was 53 years. Incidence and prevalence were both higher in women and in Asian/Asian British and Other ethnic groups. There was variation between different geographic areas, but socio-economic status did not have a marked effect. Conclusion: Nearly 1300 people have TAK in England, with >70 new cases each year apart from during the COVID-19 pandemic. These estimates, based on a 10-fold larger cohort than previous European studies, will be essential in planning and commissioning pandemic-prepared specialist services.