Covered stents versus uncovered stents for unresectable malignant biliary strictures: A meta-analysis

Aim. To summarize the covered or uncovered SEMS for treatment of unresectable malignant distal biliary obstruction, comparing the stent patency, patient survival, and incidence of adverse events between the two SEMSs. Methods. The meta-analysis search was performed independently by two of the authors, using MEDLINE, EMBASE, OVID, and Cochrane databases on all studies between 2010 and 2015. Pooled effect was calculated using either the fixed or the random effects model. Results. Statistics shows that there is no difference between SEMSs in the hazard ratio for patient survival (HR 1.04; 95% CI, 0.92-1.17; P=0.55) and stent patency (HR 0.87, 95% CI: 0.58 to 1.30, P=0.5). However, incidence of adverse events (OR: 0.74, 95% CI: 0.57 to 0.97, P=0.03) showed significant different results in the covered SEMS, with dysfunctions events (OR: 0.75, 95% CI: 0.56 to 1.00, P=0.05) playing a more important role than complications (OR: 0.87, 95% CI: 0.58 to 1.30, P=0.50). Conclusions. Covered SEMS group had lower incidence of adverse events. There is no significant difference in dysfunctions, but covered SEMS trends to be better, with no difference in stent patency, patient survival, and complications.