Abstract:

ABSTRACT Objective: To investigate the incidence, epidemiologic and clinical characteristics and risk factors of infection in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Methodology: 255 patients (male 103 and female 152，age 14～78 years) with AAV from January 1996 to December 2013 were included. The patients received induction therapy with corticosteroids with or without intravenous cyclophosphamide (IV-CYC), mycophenolate mofetil or multi-target therapy. Infection was defined as major infection and diagnosed by the clinical and radiological manifestation and microbiological evidences. The time, site, incidence and risk factors of severe infection were analyzed. Results: 103 infection episodes were found in 86 patients(28.0%) during follow-up for median 15 months(1～155 months).The infection rate of induction therapy with corticosteroids (n=65),MMF(n=77）,IV-CTX(n=66) and Tripterygium wilfordii (n=40) were 38.5%，39.0%,33.3% and 22.5% respectively. 73.8% (76/103) of the infection episodes occurred within 6 months of the induction treatment, 66 of them (64.1%) occurred within 3 months. The most common infection site was lung (n=74).The others included skin, digestive tract and urinary tract，and six cases developed sepsis. The most common pathogen was bacteria(78.6%), followed by fungus (12.6%) and virus(8.7%). COX model manifested that beforehand infection prior to the onset of AAV(RR=4.105，95%CI=2.557-6.592), serum creatinine≥6mg/dl(RR=1.179，95%CI=1.090-1.276) , and cyclophosphamide (RR=1.889，95%CI=1.020-3.500)were independent risk factors for the development of infection. The main thoracic manifestations include consolidation（51.4%）, diffused interstitial pneumonia（28.4%）and multiple nodules（17.6%）.34 cases reached end stage of renal disease during follow-up.12 of 86 patients（11.7%）died and all were due to severe pulmonary infection. Conclusion: Infection rate was high in patients with AAV, especially during the first 3 months of induction treatment. Pulmonary bacteria infection was the most common type of infection. Beforehand infection, severe renal dysfunction and cyclophosphamide were high risk factors for developing infection.

Key words: Antineutrophil cytoplasmic antibody vasculitis, infection, incidence, risk factors