Remission and Low Disease Activity in Granulomatosis With Polyangiitis and Microscopic Polyangiitis: Prevalence and Impact on Damage Accrual.

OBJECTIVE

To assess the prevalence and impact on damage accrual of different levels of disease activity in patients with granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA).

METHODS

Patients with GPA and MPA followed for ≥5 years in 2 different centers were included. Disease activity and damage were assessed using the Birmingham Vasculitis Activity Score (BVAS) and Vasculitis Damage Index (VDI), respectively. Three levels of remission were defined: complete remission (BVAS = 0, negative for antineutrophil cytoplasmic antibody [ANCA], off treatment), clinical remission off therapy (CROffT; BVAS = 0, positive for ANCA), and clinical remission on therapy (CROnT; BVAS = 0, negative or positive for ANCA, glucocorticoids ≤5 mg/day and/or immunosuppressant). A low disease activity state (LDAS) was defined as 0 < BVAS ≤3, low-dose glucocorticoids (≤7.5 mg/day), and/or immunosuppressant. Remission or LDAS were defined as prolonged when lasting ≥2 consecutive years.

RESULTS

A total of 167 patients were included: 128 (76.6%) with GPA, 39 (23.4%) with MPA, mean ± SD age 51.0 ± 16.7 years. During a 5-year follow-up, 10 patients (6.0%) achieved prolonged complete remission, 6 (3.6%) prolonged CROffT, 89 (53.3%) prolonged CROnT, 42 (25.1%) prolonged LDAS, and 20 (12.0%) never achieved LDAS. The VDI score at 5 years progressively worsened according to increasing levels of disease activity targets (complete remission, CROffT, CROnT, and LDAS). The mean ± SD 5-year VDI score was higher in patients not achieving prolonged remission compared to those who did (3.7 ± 2.0 versus 2.2 ± 1.9; P < 0.0001). By multivariate analysis, baseline ear, nose, and throat (P = 0.006), and lung involvement (P = 0.047) were negative predictors of prolonged remission.

CONCLUSION

More than 60% of patients with GPA/MPA achieved prolonged remission, which was associated with better long-term outcomes. In contrast, prolonged LDAS correlated with increased damage accrual and was not a sufficient treatment target.