Kidney Histopathology Can Predict Kidney Function in ANCA-Associated Vasculitides with Acute Kidney Injury Treated with Plasma Exchanges

Findings of the international prospective multicenter PEXIVAS trial challenge the role of PLEX in AAV. We conducted a retrospective study of 425 patients: 188 with AAV and renal failure treated with PLEX and 237 not treated. A score to identify patients who would benefit from PLEX was developed. With kidney biopsy data, scores more than seven achieved sensitivity and specificity of 83.1% and 96.0%, respectively, for recommending PLEX. The average effect of PLEX for those with recommended treatment corresponded to an absolute risk reduction for death or KRT at M12 of 24.6%. Patients in the PLEX-recommended group had microscopic polyangiitis, MPO-ANCA, higher serum creatinine, crescentic and sclerotic classes, and higher Brix score. These findings, which require independent validation, could provide guidance in selecting patients with AAV who will benefit from PLEX.