Presentation: Comparison of Predictors of Relapse in ANCA Vasculitis in 2 Independent Cohorts (2007)

2023 Comparison of Predictors of Relapse in ANCA Vasculitis in 2 Independent Cohorts

Purpose : Based on a cohort of patients with ANCA-associated vasculitis (AASV) from the southeastern USA, 3 predictors of relapse were previously identified: the presence of PR3-ANCA (vs MPO-ANCA), upper respiratory tract, and lung involvement. The aim of this study was to determine if these factors were also associated with relapse in the independent French Vasculitis Study Group (FVSG) patient cohort.
Methods: Patients with ANCA-positive microscopic polyangiitis (MPA), Wegener’s granulomatosis (WG) or pauci-immune necrotizing crescentic glomerulonephritis (NCGN) were identified near the time of diagnosis and followed prospectively. Relapse was determined according to previously established criteria. The value of each of the 3 pre-defined risk factors in predicting relapse was evaluated using Cox proportional hazards models to estimate hazard ratios (HR) controlling for age, gender, race, serum creatinine at entry, and induction treatment with cyclophosphamide.
Results:The US (n=350) and French (n=434) cohorts were similar in their age, gender, and race distributions and median duration of follow-up (49 vs 44 months respectively). They differed in the proportions of patients with PR3-ANCA (41% vs 58%), lung (49% vs 58%), upper respiratory tract disease (31% vs 62%), disease distribution (WG, 17% vs 66%; MPA, 58% vs 33%; NCGN, 25% vs 1%) and mean entry creatinine (324 vs 211 µmol/l). The table displays the HR for each risk factor in the two cohorts, also controlling for the other 2 risk factors.
Hazard ratio (HR) for each of the studied risk factors in the 2 cohorts
Hazard ratio (HR) for each of the studied risk factors in the 2 cohorts
US CohortFrench Cohort
Risk factorHR (95% CI)p-valueHR (95% CI)p-value
PR3-ANCA1.87 (1.11-3.14)0.0221.46 (1.03-2.09)0.035
Lung1.71 (1.04-2.81)0.0341.46 (1.02-1.95)0.039
Upper respiratory tract1.73 (1.04-2.88)0.0301.00 (0.69-1.46)0.981

Conclusions: PR3-ANCA and lung involvement predict relapse in both cohorts, whereas upper respiratory tract disease did not predict relapse in the French cohort. Possible reasons for the discrepancies between cohorts include differences in the disease distributions and organ involvement.

 C. Pagnoux, None; H. Chin, None; S.L. Hogan, None; L. Guillevin, None; R.J. Falk, None; P.H. Nachman, None.