ObjectiveTo analyze the clinical characteristics and renal outcome of elderly patients with antineutrophil cytoplasmic autoantibody (ANCA) associated vasculitis (AAV) with renal involvement. MethodsWe retrospectively analyzed the clinical data of 147 patients with ANCA relate vasculitis treated between June 2006 and June 2012. Based on the age, the patients were divided into elderly group (65 years or older, n=50) and non-elderly group (younger than 65, n=97). The disease course, clinical characteristics, ANCA serological indexes, renal pathological change and prognosis of patients in the two groups were compared and studied. ResultsIn the elderly group, there were 3 cases of Wegener granulomatosis (WG), 45 of microscopic polyangiitis (MPA), and 2 of pauci-immune crescentic glomerulonephritis (PICGN). The non-elderly group had 8 cases of WG, 82 of MPA, 6 of PICGN, and 1 of allergic angitis granulomatosis. There were 5 cases of positive cANCA and 44 of positive pANCA in the elderly group. The elderly patients had significantly more pulmonary involvement than the younger patients (P=0.030). No significant difference was detected between the two groups in combined pulmonary infection (P=0.281) or combined infectious index C-reactive protein (P=0.326). Elderly patients were less likely to respond to sufficient treatment with pulse intravenous methylprednisolone therapy (P=0.035) and cyclophosphamide (P=0.043), and had worse renal outcome than younger patients (P=0.040). ConclusionElderly patients with AAV have more prevalent pulmonary involvement and have severe complication of pulmonary infection, which affects mortality and morbidity of ANCA-associated systemic vasculitis.