Plasma Exchange in ANCA-Associated Vasculitis With Kidney Involvement: Differential Outcomes by Kidney Function in a Colombian Cohort.

ANCA-associated vasculitis (AAV) frequently involves the kidneys and may progress to end-stage kidney disease (ESKD). The benefit of plasma exchange (PLEX) in this setting remains uncertain. We conducted a retrospective cohort study of 163 patients with AAV and serum creatinine ≥ 1.5 mg/dL from two tertiary centers in Colombia, comparing PLEX versus no PLEX. The primary outcome was a composite of all-cause mortality or ESKD. Overall, PLEX was not associated with a reduction in the composite outcome (adjusted hazard ratio HR 1.04, 95% CI 0.61-1.76). Among patients with baseline creatinine > 5.7 mg/dL, PLEX was associated with a lower risk of ESKD (adjusted HR 0.38, 95% CI 0.14-0.97) and a borderline reduction in the composite outcome (HR 0.45, p = 0.05), with no benefit in those with lower creatinine levels. PLEX was associated with increased in-hospital infections (adjusted risk ratio 4.66, p = 0.001). These findings suggest a potential role for PLEX in selected patients with severe kidney dysfunction.