158. INCIDENCE AND PREDICTORS OF SEVERE INFECTIONS IN ANCA-ASSOCIATED VASCULITIS IN A POPULATION-BASED COHORT – PRELIMINARY RESULTS

Abstract

Background/Purpose: To determine the incidence rates, predictors and outcome of severe infections in ANCA associated vasculitis (AAV). Method(s): We conducted a population-based cohort study in Southern Sweden with 326 incident cases of AAV diagnosed between 1997 and 2016. Clinical diagnosis of vasculitis was confirmed by case record review and patients were classified according to the European Medicine Agency algorithm. Demographics, clinical, laboratory and treatment data was collected from time of diagnosis and follow-up. All events of severe infection (required hospitalization or treated by intravenous antibiotics) were identified. Vasculitis disease activity was evaluated using the Birmingham Vasculitis Activity Score (BVAS) and the extent of organ damage was assessed using the vasculitis damage index (VDI). Estimated glomerular filtration rate (eGFR) was calculated using the MDRD formula. Patients were followed from time of diagnosis of AAV to death or end of study, December 2017 Results: Data on 221 patients (96 women) was collated and are presented in this report. In total 89 (40%) patients experienced at least one severe infection during the follow-up, 25 (11%) suffered two infections and 10 (5%) suffered 3 severe infections or more. Table 1 summarizes demographics, clinical and laboratory data in this study. Compared to those who did not suffer severe infection, patients with severe infection were older at diagnosis, had higher serum creatinine, lower eGFR, were more likely to have MPO-ANCA positivity, had higher BVAS at disease onset and higher VDI after 12 months (Table 1). Age and BVAS at diagnosis were the only factors that independently predicted severe infection. The incidence rate of severe infection was higher during the first year after diagnosis compared to that during the whole follow-up time (38.6/100 year vs. 10.4/100, p<0.001). An association between steroid exposure and serious infection could not be demonstrated. Severe infection was associated with worse prognosis in terms of renal and patient's survival (Table 1) Conclusion(s): In this cohort the incidence rate of severe infection is comparable to earlier published data in AAV. Severe infection in ANCA associated vasculitis is still a major clinical problem and is associated with high age, increased disease activity at diagnosis, renal disease and MPO-ANCA positivity. The rate of severe infection is higher early in the disease course. Severe infection is associated with a worse prognosis. (Table Presented) .