The PEXIVAS study data called into question the function of plasma exchange (PLEX) in ANCA-associated vasculitides (AAV). For a study, researchers sought to characterize kidney biopsies from patients with AAV treated with PLEX to determine if histopathologic features might predict kidney function, and figure out which individuals would benefit the most from PLEX. They conducted multicenter, retrospective research on 188 patients with AAV and AKI who were treated with PLEX and 237 who were not. At 12 months, the primary outcome was death or KRT (M12).

There was no substantial advantage of PLEX for the main endpoint. To identify patients who might benefit from PLEX, they created a model that predicts the average treatment impact of PLEX for an individual based on covariables. Using the prediction model, 223 patients had a better-anticipated result with PLEX than without PLEX, and 177 of them had a more than 5% enhanced predicted probability with PLEX than without PLEX of being alive and free from KRT at M12, which characterized the PLEX-recommended group. The risk difference for mortality or KRT at M12 with PLEX was considerably lower in the PLEX-recommended group (15.9%; 95% CI, 29.4 to 2.5) compared to the PLEX not advised group (4.8%; 95% CI, 14.9 to 5.3). Microscopic polyangiitis, MPO-ANCA, increased serum creatinine, crescentic and sclerotic classes, and a higher Brix score was more common in the PLEX-recommended group. Patients who might benefit from PLEX were identified using a simple score. For those who received indicated therapy, the average therapeutic impact of PLEX was 24.6% lower absolute risk of mortality or KRT at M12.

Although PLEX was not linked with a superior main result in the overall research group, they did identify a subset of individuals who potentially benefit from PLEX. However, before they can be used to make therapeutic decisions, the findings must be confirmed.