Self-expandable metal stents versus plastic stents for unresectable malignant hilar biliary obstruction: A systematic review and meta-analysis of reconstructed individual patient data from randomized controlled trials with meta-regression

BACKGROUND: Malignant hilar biliary obstruction (MHBO) is frequently unresectable, requiring palliative endoscopic drainage. While self-expandable metal stents (SEMSs) are preferred over plastic stents (PSs), evidence regarding stent patency and patient survival remains limited. METHODS: We conducted a meta-analysis of individual patient data (IPD) from randomized controlled trials (RCTs) comparing SEMSs and PSs in unresectable MHBO. Systematic searches were performed in PubMed, Scopus, Web of Science, and the Cochrane Library on June 15, 2025. The primary outcomes were stent patency and overall survival, analyzed using reconstructed Kaplan-Meier curves and stratified Cox models, with hazard ratios (HRs) assessed. Secondary outcomes included reintervention, technical and clinical success, and adverse events, assessed using random-effects risk ratios (RRs), with 95% confidence intervals (CI) RESULTS: Out of 2106 publications screened, five RCTs comprising 322 patients were included. SEMSs significantly improved stent patency (HR, 0.49; 95% CI, 0.35-0.68) and overall survival (HR, 0.60; 95% CI, 0.47-0.78) compared to PSs. Reintervention was lower with SEMSs (RR, 0.76; 95% CI, 0.59-0.97). No significant differences were found in technical and clinical success rates, or in adverse event rates, including pancreatitis, cholecystitis, and cholangitis. CONCLUSIONS: In patients with unresectable MHBO, SEMSs offer superior stent patency and survival compared to PSs, with similar safety and procedural success. These findings reinforce previous guidelines recommending the preferential use of SEMSs for endoscopic palliation in MHBO.