Post-ERCP pancreatitis occurs more frequently in self-expandable metallic stents than multiple plastic stents on benign biliary strictures: a meta-analysis

Background The occurrence of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) after using covered self-expandable metallic stents (CSEMS) and multiple plastic stents (MPS) in the therapy of benign biliary strictures (BBS) remains ambiguous, this analysis aimed to evaluate the outcomes.Methods A systematic search of electronic databases (PubMed, Web of Science and Cochrane Library) was conducted for randomised controlled trials (RCTs), and the included studies were published between 2008 and 2021. The primary outcome was PEP, while the secondary outcomes were stricture resolution, recurrence, overall adverse events, costs, and ERCP sessions. Pooled effect sizes were calculated with the random-effects model or fixed-effects model depending on the heterogeneity.Results Six RCTs contained 444 patients (221 with CSEMS, 223 with MPS) finally included in the meta-analysis. The present analysis shows that compared to MPS, PEP is more likely to occur in CSEMS (OR [odds ratio] = 3.34, 95% confidence intervals [CI]:1.44–7.77, p = .005). CSEMS needs fewer ERCP sessions (Mean Deviation [MD]: −1.56; 95%CI:−2.66, −0.46], p = .006). The difference in stricture resolution and recurrence was not significant between the two stent types (OR = 0.87, 95%CI: 0.49–1.56, p = .64; and OR = 2.3, 95%CI: 0.68–7.76, p = .18). The incidence of overall adverse events was comparable between CSEMS and the MPS group (OR = 1.49, 95% CI: 0.97–2.29, p = .07).Conclusions Compared with MPS, CSEMS caused a significantly higher incidence of PEP but fewer ERCP procedures, while the rate of stricture resolution, recurrence, and overall adverse events were comparable. Prevention methods of PEP should be further evaluated in BBS when undergoing CSEMS placement.Systematic Review Registration PROSPERO CRD42022314864. Key messagesCSEMS and MPS placement remain a mainstay for patients with BBS, and severe complications after stent placement have not been compared.The incidence of PEP was higher after deployment of CSEMS compared to MPS.Prevention methods of PEP should be evaluated in BBS when undergoing CSEMS placement.