Thirteen RCTs (n=7,318) were included.
Major bleeding was significantly less likely with LMWH than with UFH (13 studies; pooled OR 0.57, 95% CI: 0.40, 0.82, p=0.002; no significant heterogeneity, p=0.77). The funnel plot showed no evidence of publication bias. The result was robust to the sensitivity analysis.
There was no statistically significant difference between LMWH and UFH in the risk of minor bleeding (OR 0.75, 95% CI: 0.47, 1.20, p=0.24) or in the composite outcome of major or minor bleeding (OR 0.73, 95% CI: 0.50, 1.05, p=0.09).
There was no statistically significant difference between LMWH and UFH in the composite outcome of death and MI (13 studies; OR 0.99, 95% CI: 0.79, 1.24, p=0.93; no significant heterogeneity, p=0.47). The funnel plot showed no evidence of publication bias.
There was no statistically significant difference between LMWH and UFH in the incidence of death, MI or urgent target vessel revascularisation (OR 1.02, 95% CI: 0.85, 1.22, p=0.87).
The composite efficacy and safety end point showed no statistically significant difference between LMWH and UFH (OR 0.91, 95% CI: 0.78, 1.08, p=0.29).