Risk factors for the recurrence of relapsing polychondritis

[Background] Although the survival rates of patients with relapsing polychondritis (RP) have increased remarkably, the high recurrence rate remains a significant concern for physicians and patients. This retrospective study aimed to investigate the risk factors for RP recurrence. [Methods] Patients with RP who presented to Kyoto University Hospital from January 2000 to March 2020 and fulfilled Damiani’s classification criteria were included. Patients were classified into recurrence and non-recurrence groups. Risk factors for RP recurrence were analysed using a Cox proportional hazards model, and Kaplan–Meier survival curves were drawn. [Results] Thirty-four patients were included. Twenty-five patients (74%) experienced 64 recurrences (mean: 2.56 recurrences per patient). The median duration before the first recurrence was 202 [55−382] days. The median prednisolone dose at the initial recurrence was 10 [5−12.75] mg/day. Tracheal involvement was significantly more frequent in the recurrence group at the initial presentation (44.0% vs. 0.0%, p=0.0172) than in the non-recurrence group, and pre-treatment C-reactive protein levels were significantly higher in the recurrence group than in the non-recurrence group (4.7 vs 1.15 mg/dL, p=0.0024). The Cox proportional hazards model analysis revealed that tracheal involvement (hazard ratio [HR] 4.266 [1.535−13.838], p=0.0048), pre-treatment C-reactive protein level (HR 1.166 [1.040−1.308], p=0.0085), and initial prednisolone monotherapy (HR 4.443 [1.515−16.267], p=0.0056) may be associated with recurrence. The median time before the initial recurrence was significantly longer in patients who received combination therapy with prednisolone and immunosuppressants or biologics (400 vs. 70 days, p=0.0015). [Conclusions] Tracheal involvement, pre-treatment C-reactive protein level, and initial prednisolone monotherapy were risk factors for recurrence in patients with RP. Initial combination therapy with prednisolone and immunosuppressants may delay recurrence.