To identify potential predictors by assessing adverse outcomes in ANCA-associated vasculitis (AAV) patients. Eighty-nine untreated AAV patients were followed up to January 31, 2022, death, or loss of follow-up. Clinical characteristics, laboratory tests, treatment, and progress were collected, and disease activity was evaluated via Birmingham Vasculitis Activity Score (BVAS). We determined risk factors of high-risk events, defined as developing tumors, renal replacement therapy (RRT), and death. Patients and renal survivals were computed by the Kaplan-Meier curve analysis. Cox regression analysis was performed for assessing variables for predicting death. During 267 person-years follow-up, 46 patients occurred high-risk events, including 20 patients receiving RRT, 12 patients developing tumors, and 29 patients who died mostly from organ failure and infection. Decreased estimated glomerular filtration rate (eGFR) (P < 0.001) and complement 3 levels (P = 0.019) were associated with high-risk events. Patients with lower serum potassium tended to develop tumors (P = 0.033); with higher BVAS (HR = 1.290, 95%CI 1.075-1.549, P = 0.006) and lower eGFR (HR = 0.782, 95%CI 0.680-0.901, P = 0.001) were more likely to undergo RRT. Patients with cardio and renal involvement exhibited a lower frequency of renal survival and all-cause mortality. Through multivariate COX analysis, age (HR = 1.016, 95%CI 1.016-1.105, P = 0.006) and eGFR (HR = 0.982, 95%CI 0.968-0.997, P = 0.018) predicted death in AAV, separately. The BVAS and eGFR could be a great prognosticator for RRT, while age and eGFR can independently predict the death. Serum potassium level and immunoglobulins should be focused on their predictor value in development of cancer and renal outcomes in AAV patients.