A total of three RCTs were included in this review (n=2,028, range 148 to 1,335) and there was no indication of publication bias. The median Jadad quality score was reported as 6 and no significant heterogeneity was noted.
VTE: The pooled OR favoured a significant reduction in risk of VTE with LMWH, OR 0.54 (95% CI: 0.41, 0.70; p=0.001) and similar results were found when the analysis was restricted to proximal VTE only.
Bleeding and safety: There were no significant differences between LMWH and UHF for intracerebral bleeding, OR 0.70 (95% CI: 0.26, 1.84; p=0.466), or for nonintracerebral major haemorrhage, OR 1.31 (95% CI: 0.63, 2.71; p=0.467). Mortality was reported both at the end of treatment (early) and after 90 days (late) but there was no difference in either measure between different heparin groups.
Sensitivity analysis was carried out comparing enoxaparin versus UFH, but the results did not differ significantly from those reported above.
Using a random or fixed effects analysis model did not substantially alter the results for safety and bleeding outcomes.