Pharmacological thromboprophylaxis to prevent venous thromboembolism in patients with temporary lower limb immobilization after injury : systematic review and network meta‐analysis

Background

Thromboprophylaxis has the potential to reduce venous thromboembolism (VTE) following lower limb immobilization due to injury.

Objectives

We aimed to estimate the effectiveness of thromboprophylaxis, compare different agents and identify any factors associated with effectiveness.

Methods

We undertook a systematic review and network meta‐analysis (NMA) of randomised trials reporting VTE or bleeding outcomes that compared thromboprophylactic agents to each other or to no pharmacological prophylaxis, for this indication. An NMA was undertaken for each outcome or agent used, and a series of study level network meta‐regressions examined whether population characteristics, type of injury, treatment of injury or duration of thromboprophylaxis were associated with treatment effect.

Results

Data from 6857 participants across 13 randomised trials showed that, compared to no treatment, low molecular weight heparin (LMWH) reduced the risk of any VTE (OR 0.52; 95% CrI 0.37, 0.71), clinically detected deep vein thrombosis (DVT) (OR 0.39; 95% CrI 0.12, 0.94) and pulmonary embolism (PE) (OR 0.16; 95% CrI 0.01, 0.74), while fondaparinux reduced the risk of any VTE (OR 0.13; 95% CrI 0.05, 0.30) and clinically detected DVT (OR 0.10; 95% CrI 0.01, 0.86), with inconclusive results for PE (OR 0.40; 95% CrI 0.01, 7.53).

Conclusions

Thromboprophylaxis with either fondaparinux or LMWH appears to reduce the odds of both asymptomatic and clinically detected VTE in people with temporary lower limb immobilization following an injury. Treatment effects vary by outcome and are not always conclusive. We were unable to identify any treatment effect modifiers other than thromboprophylactic agent used.