Analysis
HYPOGAMMAGLOBULINAEMIA
Results are reported for the 170 randomised patients, except for safety parameters for which data on all 188 enrolled patients are presented. The primary intention-to-treat analysis was based on a Cox proportional hazard model, adjusted for the stratification factors (ANCA type, relapse severity and prednisone induction regimen) for the difference in the distribution of relapse-free survival between the rituximab and azathioprine groups with a closed testing procedure. First, the null hypothesis was tested for a HR of 1 at all time points. If this was rejected at a 5% level, then two further subhypotheses were prespecified using time-varying covariates; up to 24 months and after 24 months. Hazard ratios and 95% CIs were reported. A p value less than 5% was considered statistically significant.Kaplan-Meier estimates for relapse-free survival at 24 and 48 months and median relapse-free survival with the corresponding 95% CIs by treatment allocation are also presented. Multivariable analysis was performed on risk factors for the development of hypogammaglobulinaemia. Data were analysed using R V.3.6.1.