Baseline features and initial treatment as predictors of remission and relapse in Wegener's granulomatosis.

OBJECTIVE: To describe the course of disease activity and determine predictors of remission and relapse in a population based cohort of patients with Wegener's granulomatosis (WG).

METHODS: Retrospective cohort study of 56 patients (median age 50 yrs) followed for 42.5 months. Disease activity was assessed by Birmingham Vasculitis Activity Score (BVAS-1) and permanent organ damage by Vasculitis Damage Index (VDI). Induction therapy consisted of prednisolone (Pred) 0.5-1 mg/kg and cyclophosphamide (CYC) daily orally 2 mg/kg (19 patients) or intravenous pulses 15 mg/kg every 2nd week (32 patients). Baseline clinical and laboratory features and cumulative treatment during the first 6 months were recorded. Multiple Cox and logistic regression analyses were used to find risk factors for remission and relapse.

RESULTS: All patients surviving > 1 month achieved either complete (85%) or partial remission (15%). Higher baseline BVAS-1 increased the likelihood of achieving complete remission [BVAS-1 > 23, relative hazard (RH) 2.94, 95% confidence interval (CI) 1.48-5.85]. Relapse occurred in 31 patients (60%) after a median period of 18 months. The risk of relapse was increased in patients having received < 10 g CYC during the first 6 months (RH 2.83, 95% CI 1.33-6.02), in patients having received Pred > 20 mg/day for < 2.75 months (RH 2.41, 95% CI 1.12-5.21), and in patients with initial heart involvement (RH 2.87, 95% CI 1.09-7.58). A higher Pred dose during the first 6 months was associated with severe infections. Therapy resistance (no complete remission) was associated with baseline organ damage (VDI increase by 1, OR 1.53, 95% CI 1.03-2.27).

CONCLUSION: Initial high disease activity increased and the presence of baseline organ damage reduced the likelihood for complete remission in WG. Relapse was associated with less intensive initial treatment in terms of lower CYC doses and shorter time taking Pred > 20 mg/day.