About 1 of every 4 patients was resistant to treatment. Most patients who were resistant to treatment reached end-stage kidney disease, meaning they needed dialysis or a kidney transplant to survive. Treatment with corticosteroids only, without the benefit of another immunosuppressive drug, was strongly correlated to treatment resistance. Women, African-American patients, and those with severe kidney disease before treatment were more likely to be resistant. Of the patients who did respond to treatment, about 40% had a relapse. Patients who had lung disease, upper airway (sinus) disease, and a specific type of ANCA called proteinase 3 (PR3) ANCA were more likely to have a relapse than patients without these characteristics.