CRP and microscopic polyangiitis: AAV, anti-neutrophil cytoplasmic antibody-associated vasculitis; AAGN, anti-neutrophil cytoplasmic antibody-associated glomerulonephritis; ANCA, anti-neutrophil cytoplasmic antibody; AUC, area under the receiver operating characteristic curve; BVAS, Birmingham Vasculitis Activity Score; CRP, C-reactive protein; eGFR, estimated glomerular filtration rate; EGPA, eosinophilic granulomatosis polyangiitis; ESRD, end-stage renal disease; GPA, granulomatosis polyangiitis; IQR, interquartile range; MPA, microscopic polyangiitis; ROC, receiver operating characteristic; RRS, renal risk score.