Background  Autoimmune pancreatitis (AIP) is a special type of benign and highly recurrent pancreatitis, and its risk factors for recurrence have not been established.

  Objective  To explore the risk factors for recurrence of type 1 AIP, so as to raise the clinical awareness of diagnosis and treatment.

  Methods  Clinical data about 103 patients with AIP admitted to Chinese PLA General Hospital from 2012 to 2020 with complete follow-up data were retrospectively analyzed. Univariate and multivariate analysis were performed to find potential risk factors and protective factors for recurrence.

  Results  Of the 103 patients with type 1 AIP, 79 cases were male and 24 cases were female, with a mean age of 61.4 ± 10.6 (range: 29-85) years. The median follow-up was 56 (range: 24-128) months, with relapse occurring in 48.5% (50/103) of cases. Univariate analysis showed that parotid involvement (P=0.032), serum IgG4>1140 mg/dL (P=0.014), serum IgG>1 945 mg/dL (P=0.033), serum gamma globulin>26.9% (P=0.028), and maintenance treatment (P=0.005) had statistically significant differences between the two groups. Results of multifactorial analysis showed that serum IgG4>1140 mg/dL (OR=2.156), receiving maintenance therapy (OR=0.642) were independently associated with type 1 AIP recurrence (P<0.05). Among them, receiving maintenance therapy was a protective factor.

  Conclusion  Serum IgG4>1 140 mg/dL at diagnosis is an independent risk factor for recurrence of type 1 AIP, and low-dose glucocorticoids maintenance therapy can reduce recurrence.