Risk Factors for Rate of Relapse and Effects of Steroid Maintenance Therapy in Patients with Autoimmune Pancreatitis: Systematic Review and Meta-analysis

BACKGROUND AND AIMS: Risk for relapse after induction of remission with steroid therapy has been extensively studied in patients with autoimmune pancreatitis (AIP), but findings are equivocal. We performed a systematic review and meta-analysis were to estimate the rate of rate of AIP following initial remission after steroid treatment and to identify factors associated with relapse.

METHODS: Three reviewers searched MEDLINE, SCOPUS and EMBASE until July 2018 to identify studies of rate of relapse of AIP rate after induction of remission with steroid therapy. A pooled estimate was calculated using DerSimonian and Laird method for a random-effects model. This study was conducted in accordance with PRISMA guidelines RESULTS: Thirty-six studies met the inclusion criteria for meta-analysis. The median follow-up time was 40.8 months. Fifty-two percent of patients were classified as having type 1 AIP. The pooled estimate of relapse rate was 33% (95% CI, 30%-37%). A higher proportion of patients with type 1 AIP had a relapse compared to patients with type 2 AIP (37.5% vs 15.9%; P<.001). We found significant heterogeneity among studies (P<.01). Long-term maintenance therapy with steroid and study quality were independently associated with AIP relapse, after we adjusted for year of publication by multivariate meta-regression.

CONCLUSION: In a systematic review and meta-analysis, we found that a large proportion of patients with AIP successfully treated with steroid induction therapy have a relapse (33%)-particularly patients with type 1 AIP (37%). Maintenance steroid therapy longer than 1 year could reduce risk of relapse. However, data characterizing relapse rate are of limited quality, indicating the need for randomized controlled trials and new immunosuppressive drugs.