Predicting factors for relapse in patients with granulomatosis with polyangiitis: results from a long-term cohort

To investigate the predictive factors and the best predictive model for relapse in granulomatosis with polyangiitis (GPA) patients.

All patients referred to our tertiary university hospital with confirmed diagnosis of GPA based on 1990-ACR criteria and/or revised Chapel Hill nomenclature, who were followed more than 24 months between 2012 and 2021 were included. Patients were classified into relapsing and non-relapsing groups. Disease activity was assessed based on Birmingham Vasculitis Activity Score (BVAS) and BVAS for GPA (BVAS-GPA). All demographic, clinical, laboratory, and radiologic parameters were compared between two groups.

Data of 133 patients (male = 52 (39.1%); mean age = 46.5 ± 14.5 years) with a mean follow-up period of 49.4 ± 24.1 months were evaluated. Of those, 91 (68.4%) experienced at least one relapse episode. The mean duration of relapse-free-survival (RFS) was 12.5 months with 1-year, 3-year, and 5-year RFS rates of 46.6%, 34.6%, and 31.6%, respectively. The risk of relapse was higher if patients had higher BVAS or BVAS-GPA score (P-values < 0.001), constitutional syndrome (P-value = 0.01), neutrophil-to-lymphocyte ratio (NLR) (P-value = 0.01), C-reactive-protein (P-value = 0.03), alanine transaminase > 40 units/L (P-value = 0.04), and microscopic hematuria (P-value = 0.001). In backward logistic regression analysis, baseline BVAS score ≥ 12 (Ex(B) = 4.21, P-value = 0.03), and NLR > 2.5 (Ex(B) = 12.00, P-value = 0.007) remained statistically significant at the last step of the model with 75.8% sensitivity, 76.9% specificity, and 76.3% accuracy in predicting the relapsing patients. The frequency of relapse episodes was significantly lower in treatment group of rituximab-rituximab (0.3 ± 0.6) compared to cyclophosphamide-methotrexate (1.2 ± 1.3) and cyclophosphamide-azathioprine (1.8 ± 1.5) treatment protocols (P-value = 0.002).

High-risk patients according to proposed model should be prioritized for more intensive care, more aggressive treatment, and closer follow-ups.

• During the mean follow-up period of 50 months, 68.4% experienced at least one relapse episode • Patients with baseline BVAS > 12, renal involvement, and elevated NLR are more vulnerable to relapsing disease • Patients on rituximab for induction and maintenance less experienced relapse episodes compared to other treatment regimens.