Extended duration of thromboprophylaxis for medically ill patients: a systematic review and meta-analysis of randomised controlled trials

Background: The benefit of extended-duration thromboprophylaxis in patients hospitalised for acute medical illness beyond hospital stay remains controversial. Aims: To perform a meta-analysis of randomised controlled trials (RCT) in order to examine the efficacy and safety of extended-duration anticoagulation for venous-thromboembolism (VTE) prophylaxis in this high-risk population. Methods: An electronic database search was conducted to include all RCT comparing between extended-duration versus short-duration prophylactic anticoagulation in medically ill patients. The primary efficacy outcome was the composite events of asymptomatic deep vein thrombosis (DVT), symptomatic VTE and death from VTE-related causes. Results: Five RCT were included totalling 40 124 patients, with a mean age of 71 years and 51% were male. In comparison to standard-duration therapy, extended-duration thromboprophylaxis was associated with a significant reduction in the primary efficacy outcome (risk ratio (RR) 0.75; 95% confidence interval (CI) 0.67-0.85; P < 0.01), symptomatic VTE (RR 0.53; 95% CI 0.33-0.84; P < 0.01) and asymptomatic DVT (RR 0.81; 95% CI 0.71-0.94; P < 0.01). However, there were no significant differences between both groups with regard to VTE-related death (RR 0.81; 95% CI 0.60-1.10; P = 0.18) or all-cause death (RR 0.97; 95% CI 0.88-1.08; P = 0.64). In contrast, extended-duration thromboprophylaxis was associated with an increased risk of major bleeding (RR 2.04; 95% CI 1.42-2.91; P < 0.01) and non-major clinically relevant bleeding (RR 1.81; 95% CI 1.29-2.53; P < 0.01). Conclusions: Among hospitalised medically ill patients, prolonging venous thromboprophylaxis was associated with a decreased risk of composite events of the primary efficacy outcome and increased risk of bleeding with no significant difference in VTE-related death.