French Vasculitis Study Group Score: A Predictor of Outcome or a Tool for Guiding Remission-Induction Therapy?

Background: Patients with antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) develop end-stage kidney disease, despite progress in therapy. To choose patients for whom PLEX would be helpful, the French Vasculitis Study Group (FVSG) suggested a score combining clinical and histopathologic data (Fig. 1). The aim of our study was to evaluate this score's clinical usefulness in patients with AAV. Methods: This is a retrospective, single-center cohort study. We enrolled adult patients with AAV (kidney biopsy, suggestive clinical features and/or ANCA positivity) between 2011 and 2023. The use of PLEX was uncontrolled. Patients were classified according to the FVSG score and divided in two groups (score >7 the threshold above which PLEX was recommended and <7). Baseline parameters, overall survival, and renal survival were compared. We further compared the subpopulation that received PLEX with those receiving only immunosuppressive drugs, using the same threshold. Results: The baseline data of the 33 patients are described in table 1. PLEX was performed in 16 patients (48.4%). Serum albumin and creatinine levels were significantly different between the two groups (PLEX vs. no-PLEX, p=0.008). The overall survival and renal survival of patients with score >7 was lower than the patients with score <7 (p=0.015 and p=0.012, respectively, Fig 2.). We found no differences between groups (PLEX vs no-PLEX) for patients with a clinical score >7 (table 2 and Fig. 3). Conclusion: The FVSG score was successfully used to predict overall and renal survival using the threshold proposed. However, in our retrospective cohort, the patients that would have a survival benefit with PLEX, had similar outcomes to those who did not receive it. In conclusion, in our cohort, this score was predictive of clinical outcome, however it was not helpful at differentiating patients who would benefit from receiving PLEX.