Double-Filtration Plasmapheresis versus Therapeutic Plasma Exchange in the Treatment of Anti-Glomerular Basement Membrane Nephritis: A Cohort Study.

Abstract

Background: Therapeutic plasma exchange (TPE) is acknowledged as the standard therapy for anti-glomerular basement membrane (GBM) nephritis. In recent years, double-filtration plasmapheresis (DFPP) has been proposed as an equally effective plasmapheresis modality. The present study aimed to compare the efficacy and safety of TPE and DFPP for the treatment of anti-GBM nephritis.

Methods: We conducted a retrospective cohort study of anti-GBM patients who received plasmapheresis from February 2011 to October 2023 at West China Hospital of Sichuan University. The primary outcome was a composite endpoint of in-hospital death or dialysis dependency at discharge. The secondary outcomes included length of hospitalization, long-term mortality and end-stage renal disease (ESRD). We also compared anti-GBM antibody titer reduction, plasmapheresis-related adverse events. Logistic regression and Cox hazard proportional regression analyses were performed to investigate potential risk factors of primary outcome and long-term patient/renal survival.

Results: In total, 58 anti-GBM nephritis patients were included in this study. No significant differences were observed in the incidence of primary outcome between patients receiving DFPP and TPE in fully adjusted logistic regression model (OR=0.23, 95% CI=0.04-1.37, P=0.106). In surviving patients, the length of hospitalization was similar (21 vs. 23 days, P=0.165). With a follow-up of 3-years, K‒M survival analysis revealed similar risk of death or ESRD between the 2 groups (P=0.424; P=0.987). According to fully adjusted Cox regression analyses, anti-GBM nephritis patients receiving DFPP achieved comparable patient (HR=1.18, 95% CI=0.23-6.04; P=0.845) and kidney survival (HR=0.96, 95% CI=0.13-6.86; P=0.967) to those receiving TPE. After plasmapheresis treatment, the anti-GBM antibody concentration significantly decreased in both groups (DFPP: 136.47 vs 27.20 AU/mL, P<.001; TPE: 122.09 vs 27.40 AU/mL, P=0.016), with fewer allergy episodes observed in the DFPP group (13.64% vs 42.86%, P=0.049). Besides, older age and concomitant infection were independently related to 3-year patient mortality (P<0.001, P=0.031), whereas high-dose methylprednisolone treatment seemed to be associated with a lower risk of ESRD (P=0.034).

Conclusions: Anti-GBM nephritis patients who received DFPP achieved comparable short- and long-term prognosis to those who received TPE. With less plasma consumption, DFPP was also associated with fewer allergy episodes. DFPP might be an alternative modality of plasmapheresis for anti-GBM nephritis, especially in the setting of limited blood resources.