The factors predicting development of serious infections in ANCA-associated vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare autoimmune disease usually involving small vessels and progressing with necrotizing inflammation. Treatment requires long-term use of immunosuppressive agents to inhibit disease activity. Serious infections (SIs) are a common complication in AAV.

The aim of this study was to identify the risk factors for serious infections which required hospitalization in patients with AAV.

In this retrospective cohort study., we included 84 patients admitted to the Ankara University Faculty of Medicine in the last 10 years with a diagnosis of AAV.

In 42 (50%) of 84 patients followed up with the diagnosis of AAV, an infection requiring hospitalization was identified. The patients' total corticosteroid dose, use of pulse steroids, induction regimen, levels of C-reactive protein (CRP) and the presence of pulmonary and renopulmonary involvement were found to be associated with the frequency of infection (p=0.015, p=0.016, p=0.010, p=0.03, p= 0.026 and p=0.029, respectively). In multivariable analysis, it was found that renopulmonary involvement (p=0.002, HR=4.95, 95% CI= 1.804-13.605), age of over 65 (p=0.049, HR=3.37, 95% CI=1.004-11.369) and high CRP levels (p=0.043, HR=1.006, 95% CI=1.000-1.011) constituted independent predictors of serious infection risk.

The frequency of infection is known to be increased in ANCA-associated vasculitis. Our study showed that renopulmonary involvement, age and elevated CRP levels on admission are independent risk factors of infection.