Extended thromboprophylaxis for medically ill patients with decreased mobility: does it improve outcomes?

Duration of thromboprophylaxis beyond hospital discharge for medically ill patients has been controversial. Therefore an evaluation was made of the evidence currently available.

A search was made of the Pub Med, CENTRAL and EMBASE databases for randomized controlled trials from 1966 through to 2011. Interventions included thromboprophylaxis administered over an extended period in patients hospitalized for acute medical illness with decreased level of mobility. No differentiation was made for the medication used for individual studies. The comparator included standard medical therapy and/or placebo. The efficacy outcomes assessed were a composite of asymptomatic and symptomatic deep vein thromboses (DVT), pulmonary emboli (PE) and venous thromboembolism (VTE)-related deaths in the intervention group vs. the comparator group, as well as the safety outcomes evaluated with rates of bleeding events at the end of at least 30 days of follow-up. The methodological quality of the studies was assessed, as was publication bias. Event rates were compared using a forest plot of relative risk (RR; 95% confidence interval (CI)) using a random effects model (Mantel-Haenszel) between the active thromboprophylaxis and controls. Statistical analysis was carried out with Review Manager V5.1.

Three recent studies were included. Extended duration thromboprophylaxis reduced the combined composite event rate, RR 0.75 (0.64, 0.88). However, individual clinical endpoints were not significantly improved with extended prophylaxis: asymptomatic proximal DVT, RR 0.85 (0.68, 1.05); symptomatic DVT, RR 0.44 (0.19, 1.00); symptomatic non-fatal PE, RR 0.80 (0.43, 1.48); VTE-related death, RR 0.64 (0.38, 1.10). However, bleeding events were far more prevalent with extended thromboprophylaxis with major bleeds, RR 2.68 (1.78, 4.05), with a number needed to harm of 194.

Currently available evidence does not indicate that routine administration of post-discharge prophylaxis will be beneficial to the patients admitted for medical illness.