Relapse Predictors of Idiopathic Retroperitoneal Fibrosis: A Long-Term Cohort Study

This study aims to identify predictive factors for the relapse of idiopathic retroperitoneal fibrosis (IRF) and provide instructions for the optimization of the maintenance therapy.

All patients with a clinical diagnosis of IRF were enrolled and followed up every 3-6 months. Their clinical characteristics, laboratory data and treatment strategies were recorded at each visit.

96 IRF patients (77 males and 19 females) with a median age of 55 years (interquartile range [IQR], 50-61) were enrolled. The median follow-up time was 2.50 (IQR, 1.75-4.13) years. During the follow-up, 21 patients experienced at least one relapse, with cumulative relapse rates of 10.6%, 32.3%, and 62.4% at 2.5, 5, and 7.5 years, respectively. Initial hydronephrosis was an independent predictor of relapse (Hazard ratio [HR], 5.35; p=0.001). Discontinuation of maintenance therapy (HR, 3.41; 95% CI, 1.4-8.314; p=0.007) was closely associated with relapse. Use (HR, 0.12; p<0.001) and dose (HR, 0.73; p=0.01) of glucocorticoids (GC) in maintenance period were protective factors against relapse. Among patients with hydronephrosis, those who discontinued GC had a higher relapse rate (p=0.009). GC monotherapy or combined immunosuppressants (IM) therapy were more effective in preventing relapse than IM alone (p<0.001).

Our study reveals that initial hydronephrosis and GC withdrawal during maintenance therapy are significant predictors of IRF relapse. Long-term, low-dose GC therapy is benefit for maintaining remission and preventing relapse, especially in patients with initial hydronephrosis.