The data on comparisons of stent patency, re-intervention rate and patient survival between metal and plastic stents in palliation of malignant biliary obstruction have never been pooled. We carry out a meta-analysis to summarise current evidence for clinical efficacy of metal and plastic stents in the treatment of malignant biliary obstruction.

A comprehensive search of several databases was conducted. A fixed-effects or random-effects model was used to pool data of all study endpoints. Sensitivity analysis and subgroup analysis (distal vs. hilar biliary obstruction) were also performed.

Ten randomized clinical trials were identified. Compared with plastic stents, metal stents were associated with a significantly longer stent patency (HR=0.36; 95% CI: 0.28–0.47; I²=0%), fewer numbers of re-intervention (WMD=0.59; 95% CI: 0.28–0.90; I²=76.4%) and longer patient survival (HR=0.74; 95% CI: 0.64–0.85; I²=16.0%). These results were still significant by sensitivity analysis. All outcomes reached statistical significance except of the pooled WMD of number of re-intervention in the studies with hilar biliary obstruction. No publication bias was observed.

Metal stents were associated with a significantly longer stent patency, lower re-intervention rate and longer patient survival in palliation of malignant biliary obstruction when compared to plastic stents.