Long-Term Outcomes of Low-Dose Steroid Induction for Autoimmune Pancreatitis: A Multicenter Retrospective Study Identifying Risk Factors for Relapse.

BACKGROUND: Steroids are the first-line treatment for autoimmune pancreatitis (AIP); however, the impact of lower initial doses on relapse remains unclear. METHODS: Ninety patients were divided into high-dose (HD; > 0.4 mg/kg/day) and low-dose (LD; ≤ 0.4 mg/kg/day) induction groups. The treatment response, relapse rate, and predictors of relapse were evaluated. RESULTS: Sixty-two and 28 patients received HD and LD steroid induction. The treatment response (100% vs. 100%, p > 0.99), relapse rates (33.9% vs. 32.1%, p > 0.99) and relapse-free survival (hazard ratio [HR]: 0.86; log-rank test, p = 0.99) did not differ significantly between the groups. Multivariable analysis identified discontinuation of maintenance treatment within 3 years (HR: 5.32, p = 0.0004), larger pancreatic volume (HR: 1.02, p = 0.01), and a smaller IgG4 reduction rate at 1 month after initiation of steroid treatment (HR: 0.99, p = 0.02) as independent predictors of relapse. In contrast, LD steroid induction was not identified as a risk factor for relapse (HR: 0.99, p = 0.99). CONCLUSIONS: There were no significant differences between LD and HD steroid induction in terms of treatment efficacy or long-term outcomes in patients with AIP.