Comorbid infections in patients with ANCA-associated systemic vasculitis: a prospective cohort study

State-of-the-art management of ANCA-associated vasculitis (AAV) has significantly improved patient survival, but is associated with an increased risk of infectious complications, that currently are one of the leading causes of hospitalization and mortality in patients with AAV. Objective: to assess the incidence and structure of comorbid infections in patients with AAV. Material and methods. In this prospective cohort study, we enrolled 130 patients over 18 years of age diagnosed with AAV, including 87 patients with granulomatosis with polyangiitis, 32 with microscopic polyangiitis and 11 with eosinophilic granulomatosis with polyangiitis. In all patients primary medical records were analyzed, BVAS and VDI indices were calculated. Dynamic follow-up was performed monthly for 12 months. The primary endpoint in the study was an episode of infection registered at the next contact with the patient, secondary endpoints were severe infections. Results and discussion. During the 12 months of follow-up in 130 patients 281 cases of various infectious diseases were reported (238 episodes of infections per 100 patient-years, 95% CI 209–270), with patients most commonly reporting episodes of upper respiratory tract infections. Among all infections, there were 23 cases (19.5 episodes per 100 patient-years, 95% CI 12.2–30.9) of severe infections in 14 patients and 3 deaths due to infectious complications. Conclusions. The results of our study demonstrate a high incidence of infectious diseases including severe infections in patients with AAV and emphasize the relevance of infectious complications as a factor associated with adverse outcomes in patients with AAV.