On the epidemiology of antineutrophil cytoplasmic antibody-associated vasculitis in the adult population of Russia

Objective: to assess the trends in overall incidence and the distribution of antineutrophil cytoplasmic antibody (ANCA)-associated systemic vasculitis (AAV) in the adult population in federal district and across the Russian Federation during 2022–2023, based on data from the Nasonova Research Institute of Rheumatology. Material and methods. The study is based on data collected via a federal-level inquiry addressed to regional healthcare departments concerning the organization of care and drug provision for patients with AAV in 2022–2023. The responses were qualitatively and quantitatively analyzed by experts from the N.A. Semashko National Research Institute of Public Health (Semashko NRIPH). Additionally, a retrospective single-center study was conducted involving adult patients (≥18 years) with AAV who received outpatient or inpatient care at the V.A. Nasonova Research Institute of Rheumatology (Nasonova RIR) from September 1, 2020, to October 1, 2024, with data obtained from the “Interin” system. Incidence was analyzed in absolute (the total number of registered patients aged ≥18) numbers and relative numbers (per 100,000 adult population) across Russia, in eight federal districts, and three climate/geography-based regions (Northern, Central, Southern). The frequency of antemortem kidney and/or nasal mucosa biopsy for diagnosis of AAV was also assessed. Results and discussion. According to Semashko NRIPH, a total of 1,785 AAV patients were identified during 2022–2023. The national incidence of granulomatosis with polyangiitis (GPA) ranged from 2.63 to 1.86 per 100,000, microscopic polyangiitis (MPA) from 0.79 to 1.11, and eosinophilic granulomatosis with polyangiitis (EGPA) from 1.16 to 0.98. The greatest incidence and maximal rate of decrease was seen in GPA (-29.28%) and EGPA (-15.52%), while MPA showed a maximal increase in incidence (+40.51%) in the Northern region. Substantial differences were noted across federal districts.Based on data from the Nasonova RIR, AAV was confirmed in 506 patients, most of whom were women (63%) from the Central region (p<0.001), with a gender gradient by region. Among 67 (13.2%) ANCA-negative patients with atypical presentations, kidney biopsy was more commonly performed (71.6%) than nasal mucosa biopsy (28.3%), p<0.001. Conclusion. This pilot study revealed regional and gender-related differences in AAV incidence across Russia, as well as low frequency of antemortem biopsy of kidney/nasal mucosa. These findings warrant further in-depth investigation into factors influencing these trends.