Birmingham vasculitis activity and chest manifestation at diagnosis can predict hospitalised infection in ANCA-associated vasculitis

We investigated the development rate and time, risk factors, predictors, and aetiologies of hospitalised infection in Korean patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). We retrospectively reviewed the medical records of 154 patients with AAV. Hospitalised infection was considered only when patients were admitted for serious infection related to AAV or AAV treatment. The gap-time was defined as the period from diagnosis to the first hospitalised infection or to the last visit for uninfected patients. We calculated Birmingham vasculitis activity score (BVAS) or BVAS for granulomatosis with polyangiitis (GPA) and five factor score (FFS (2009)) and reviewed medications administered. We set the optimal cut-offs of BVAS and that of FFS (2009) at diagnosis at 20.5 and 1.5. Forty-four patients (28.6%) were admitted for serious infection. One-, 5- and 10-year hospitalised infection free survival rates were 85.1, 77.9 and 72.7%, respectively. In multivariable logistic regression analysis of significant variables in comparison analysis, only chest manifestation at diagnosis (OR 2.692) was remarkably associated with hospitalised infection. In multivariable Cox hazard model analysis of significant variables in Kaplan-Meier analysis, BVAS at diagnosis ≥ 20.5 (HR 2.375) and chest manifestation at diagnosis (HR 2.422) were independent predictors of hospitalised infection during the gap-time. Bacterial pneumonia was the most common infectious aetiology (N = 29), followed by fungal infection including aspergillosis (N = 6). BVAS and chest manifestation at diagnosis can predict hospitalised infection during the gap-time.