Activity and damage in granulomatosis with polyangiitis.

Aim: To retrospectively analyze disease activity and damage-associated factors in granulomatosis with polyangiitis (GPA) in Turkey.

Method: A retrospective analysis was carried out in 21 GPA patients. Assessments for activity were performed with the Birmingham Vasculitis Activity Score for GPA (BVAS/GPA) and for permanent organ damage by the Vasculitis Damage Index (VDI).

Results: Lower BVAS/GPA (P = 0.002), absence of renal involvement (P = 0.003) and higher creatinine clearence (P = 0.000) at diagnosis increased the likelihood of achieving remission at 6 weeks. Relapses were associated with high creatinine clearence (P = 0.021), low BVAS/GPA (P = 0.014), absence of renal involvement (P = 0.036) and proteinuria (< 0.5/24 h) (P = 0.013) at diagnosis, whereas achieving remission at 6 weeks (P = 0.012) was associated with absence of co-trimoxazole usage (P = 0.038) and less severe clinical subgroup (P = 0.034). Lower cumulative first 6 months of cyclophosphamide and methylprednisolone were associated with earlier (≤ 12 months) relapses (P = 0.048 and P = 0.083, respectively). Baseline damage (VDI ≥ 1) was associated with a delay in diagnosis (P = 0.032), presentation with milder clinical subgroups (P = 0.052) and low serum creatinine (P = 0.013). The increase in VDI in the first 12 months (early damage) constituted most (91%) of the total damage measured at the end of follow-up.

Conclusions: Despite high early remission rates, relapse represents a major problem in localized GPA in our study. Baseline damage was associated with longer diagnostic delay and lower baseline serum creatinine. The initial phase of the disease seems to be the most crucial period for mortality and accumulated damage.