The incidence of vasculitides in Israel from 2007 to 2021 and during the COVID-19 pandemic.

Background: The incidence of various types of vasculitis conditions over time, specifically during coronavirus disease 2019 (COVID-19), is unknown.

Objectives: We aimed to assess recent trends in vasculitides and the effect of the COVID-19 pandemic on these trends.

Design: We conducted a retrospective analysis of Israel's largest Health Maintenance Organization, which covers over 4.7 million patients and represents 55% of the country.

Methods: We calculated the age- and sex-adjusted incidence of giant cell arteritis (GCA), Takayasu, ANCA-associated vasculitis (AAV), IgA vasculitis, cryoglobulinemia, and Behcet's disease (BD) during 2007-2021. We analyzed associations of COVID-19 with the incidence of each of the examined conditions.

Results: During 2007-2021, the adjusted annual incidence decreased from 7.9 (95% confidence interval (CI) 3.5-17.9) to 1.5 (95% CI 0.7-3.6) per 100,000 for GCA, from 5.2 (95% CI 2.7-11.1) to 1.5 (95% CI 0.7-3.3) per million for IgA vasculitis, and from 6.3 (95% CI 3.0-13.5) to 1.0 (0.5-2.5) per 100,000 for BD. The relative risks for these conditions decreased: 0.92 (95% CI 0.91-0.93), 0.93 (95% CI 0.89-0.98), and 0.90 (95% CI 0.85-0.94), respectively. The incidences of Takayasu, AAV, and cryoglobulinemia remained unchanged. The COVID-19 pandemic was not associated with changes in the incidence of any examined vasculitides.

Conclusion: The incidences of GCA, IgA vasculitis, and BD decreased substantially in Israel during 15 years and were unaffected by the COVID-19 pandemic. Future studies should focus on possible environmental contributions to these findings.