Determination of the duration of glucocorticoid therapy in type 1 autoimmune pancreatitis: A systematic review and meta-analysis

The indications for maintenance glucocorticoid therapy (MGT) and its duration after initial remission of type 1 autoimmune pancreatitis (AIP) remain controversial. In contrast to the Japanese treatment protocol, the Mayo protocol does not recommend MGT after initial remission. This study aimed to evaluate the relapse rate in patients with type 1 AIP according to the duration of glucocorticoid therapy. We conducted a systematic literature review up until November 30, 2020, and identified 40 studies reporting AIP relapse rates. The pooled relapse rates were compared between groups according to the protocol and duration of glucocorticoids (routine vs. no MGT; glucocorticoids ≤6 months vs. 6–12 months vs. 12–36 months vs. ≥ 36 months). The pooled rates of adverse events related to glucocorticoids were also evaluated. Meta-analysis indicated calculated pooled relapse rates of 46.6% (95% confidence interval (CI), 38.9–54.3%) with glucocorticoids for ≤ 6 months, 44.3% (95% CI, 38.8–49.8%) for 6–12 months, 34.1% (95% CI, 28.6–39.7%) for 12–36 months, and 27.0% (95% CI, 23.4–30.6%) for ≥ 36 months. The rate of relapse was also significantly lower in patients with routine-use protocol of MGT (31.2%; 95% CI, 27.5–34.8%) than in patients with no MGT protocol (44.1%; 95% CI, 35.8–52.4%). Adverse events were comparable between groups. The rate of relapse tended to decrease with extended durations of glucocorticoid therapy up to 36 months. Clinicians may decide the duration of glucocorticoids according to patient condition, including comorbidities and risk of relapse.