Mortality in Contemporary ANCA-Associated Vasculitis: A 10-Year Retrospective Study from the United Kingdom (UK)

Background: ANCA-associated vasculitis (AAV) is associated with increased mortality compared to the general population, as shown in several large, population-based studies. However, contemporary data from UK-based AAV cohorts remain limited. This study evaluates mortality outcomes in a recent incident AAV cohort over a ten-year period. Methods: We assembled a cohort of patients diagnosed with incident AAV between 2013 and 2023 in the Lancashire and South Cumbria region of the UK. Demographic, treatment, and outcome data were retrospectively collected. Patients were followed until death or April 2025. Mortality rates were calculated per 1,000 person-years, and standardized mortality ratios (SMRs) were estimated using age- and sex-specific mortality rates from the UK Office for National Statistics. Results: Among 239 patients followed over 1,399.5 person-years, 65 (28%) died, yielding a mortality rate of 46.4 per 1,000 person-years. The median age at death was 78 years (IQR 9), and the median age at diagnosis was 68 years (IQR 20). One-year mortality rate was 7.4 per 1,000 person-years, rising to 11.4 by year two and 26.5 by year five. The overall SMR was 9.13 (95% CI: 7.05–11.6). In MPO-positive patients, the SMR was 9.64 (95% CI: 7.03–12.9), and in PR3-positive patients, 7.4 (95% CI: 4.40–11.7). Infection remained the leading cause of death throughout follow-up. Conclusion: This UK-based cohort reinforces findings from North America and Australia, confirming that AAV continues to confer significantly elevated mortality risk despite advances in therapy and management. Infection remains a major contributor to mortality and a persistent clinical challenge.