Predictors of treatment resistance and relapse in Chinese patients with antineutrophil cytoplasmic antibody-associated disease.

OBJECTIVE: The prevalence and significance of treatment resistance and relapse in patients from China with antineutrophil cytoplasmic antibody-associated (ANCA) disease are poorly understood.
METHODS: A total of 98 patients with ANCA vasculitis, diagnosed between January 2003 and December 2009 in the China-Japan Friendship Hospital, were enrolled in this retrospective study.
RESULTS: Fifteen patients (15.3%) were categorized as having cytoplasmic and/or proteinase 3 (PR3) ANCA and 83 patients (84.7%) had perinuclear and/or myeloperoxidase (MPO) ANCA. After the induction phase treatment, the disease was resistant to therapy in 24 (25%) of the patients. A response to initial treatment occurred in 74 patients (75%). Of these 74 patients, remission was achieved and sustained with or without maintenance therapy in 41 patients (55%). Multivariable logistic regression models revealed that female sex was a statistically significant predictor of treatment resistance (OR 2.85; 95% CI: 1.06-2.86; p = 0.036). Additionally, elevated serum creatinine level, with each increment of 150 μmol/l, predicted resistance (p = 0.002). Among the 74 patients where remission was achieved, Cox proportional hazards models detected that those with PR3 ANCA were 1.31 times more likely to experience a relapse than were patients with MPO ANCA (95% CI: 1.01-5.35; p = 0.0001). Lung involvement was associated with an increased risk of relapse (HR 1.87; 95% CI: 1.12-4.35; p = 0.014). Although not significant, advanced age tended to be associated with relapse (p = 0.08).
CONCLUSION: Our findings highlight the important effect of female sex and severity of renal disease at presentation as predictors of treatment resistance, and PR3 ANCA and lung involvement as predictors of relapse.