Abstract
Aim: We aimed to determine the incidence of anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) in the Waitaha Canterbury Region, and to describe the clinical characteristics, time to relapse, rate of remission and survival.
Methods: Incident cases of AAV diagnosed between 1 January 2016 and 31 December 2020 were identified. Electronic medical records were reviewed from the date of diagnosis until 31 December 2021, last clinical encounter or death. Incidence was calculated and survival was estimated through Kaplan-Meier plots.
Results: Forty-six cases of AAV were identified, giving an incidence of 1.70 cases per 100,000 per annum over the 5 years (95% confidence interval 1.25-2.27). There was no change in incidence over time. The mean (standard deviation) age at diagnosis for any type of AAV was 66.8 (13.3) years. Remission was achieved in 38/46 (82.6%) patients by 3 months and 35/38 (92.1%) by 18 months. There were 11 deaths (23.4%), with three occurring within the first 12 months of diagnosis.
Conclusion: Despite the limited availability of rituximab, survival at 5 years is similar to international studies. There has been no clear change in incidence of AAV over time.