MPO and microscopic polyangiitis: Relapses were observed in 81 of 218 patients (35.1%) and were higher in the c-ANCA/PR3 ( +) group compared to p-ANCA/MPO ( +) (42.5% vs 29%; p = 0.049, Odds ratio [OR]:3.9) and tended to be higher in patients with GPA compared to MPA (38.7% vs 25.8%; p = 0.07).