Incidence of recurrent and chronic pancreatitis after acute pancreatitis: a systematic review and meta-analysis

Background: Acute pancreatitis (AP) has a high incidence, and patients can develop recurrent acute pancreatitis (RAP) and chronic pancreatitis (CP) after AP.Objectives: We aimed to estimate the pooled incidence rates (IRs), cumulative incidences, and proportions of RAP and CP after AP.Design: A systematic review and meta-analysis of studies reporting the proportion of RAP and CP after AP.Data sources and methods: The systematic search was conducted in three (PubMed, EMBASE, and CENTRAL) databases on 19 December 2023. Articles reporting the proportion of RAP or CP in patients after the first and multiple episodes of AP were eligible. The random effects model was used to calculate the pooled IR with 95% confidence intervals (CIs). The I2 value assessed heterogeneity. The risk of bias assessment was conducted with the Joanna Briggs Institute Critical Appraisal Tool.Results: We included 119 articles in the quantitative synthesis and 29 in the IRs calculations. Our results showed that the IR of RAP in adult patients after AP was 5.26 per 100 person-years (CI: 3.99-6.94; I2 = 93%), while in children, it was 4.64 per 100 person-years (CI: 2.73-7.87; I2 = 88%). We also found that the IR of CP after AP was 1.4 per 100 person-years (CI: 0.9-2; I2 = 75%), while after RAP, it increased to 4.3 per 100 person-years (CI: 3.1-6.0; I2 = 76%). The risk of bias was moderate in the majority of the included studies.Conclusion: Our results showed that RAP affects many patients with AP. Compared to patients with the first AP episode, RAP leads to a threefold higher IR for developing CP.Trial registration: Our protocol was registered on PROSPERO (CRD42021283252).