Factors Associated With Relapses and Performance of the French Vasculitis Study Group Relapse Score in a Cohort of Mexican Patients With Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

Background/objective: Relapses occur in 14% to 44% of patients with antineutrophil cytoplasm antibody-associated vasculitis (AAV). The French Vasculitis Study Group Relapse Score (FRS) was recently proposed to predict relapse risk. This study aimed to identify relapse-associated factors and evaluate the FRS performance in a Mexican cohort.

Patients and methods: We performed a medical records review study including patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) who were followed for ≥12 months at a Mexican tertiary care center. Demographic, clinical, laboratory, and treatment data were analyzed using descriptive statistics, survival analysis, and ROC curves.

Results: Among 147 patients (110 GPA, 37 MPA), the median age at diagnosis was 49 years (IQR: 36 to 59). Over a median follow-up of 93 months (IQR: 48 to 152), 90 patients (61%) relapsed. Cumulative relapse rates at 12, 24, 36, 48, and 60 months were 13.6%, 32.3%, 40.3%, 47.5%, and 58.0%, respectively. FRS scores of 1, 2, and 3 corresponded to median relapse-free survivals of 85, 68, and 33 months, with 5-year relapse risks of 40.5%, 48.4%, and 68.3%, respectively. Discrimination was significant (log-rank p < 0.0004). The C-statistic for FRS alone was 0.648 (95% CI: 0.586-0.710); for model 1 (adding cluster 4), 0.666 (95% CI: 0.605-0.728); and for model 2 (adding cluster 4 and rituximab as maintenance), 0.700 (95% CI: 0.643-0.757). An age cutoff of ≤50 years showed better accuracy (AUC: 0.67, p = 0.0006) for relapse prediction.

Conclusions: In this cohort, relapses were frequent. Incorporating clinical clusters and rituximab therapy to the FRS may enhance its predictive performance.