Does ambulation modify venous thromboembolism risk in acutely ill medical patients?

In the US ambulatory status is often a criterion for stopping prophylax is for venous thromboembolism (VIE) In an analysis of the prophylax is in MEDical patients with ENOXaparin (MEDENOX) trial ambulatory status was assessed as outcome and patients grouped accordingly for further analysis Rates of VIE and bleeding were evaluated Using multivariate logistic regression the relationships between thromboprophylaxis, VTE risk, and ambulatory status were assessed Ambulatory status was reached in 607/1,084 patients in a mean time of 44 days Thromboprophylaxis was provided for 7 3 and 7 7 days in the ambulatory and non ambulatory groups Although VIE rates were lower in ambulatory patients, enoxaparin 40 mg once daily significantly reduced the risk of VIE vs placebo in ambulatory (33% vs 10 6% relative risk [RR] = 031 95% confidence interval [Cl] 0 13-078 p=0 008) and non ambulatory patients (9 0% vs 19 7%, RR = 0 46 95% Cl 0 23-0 91 p=0 02) Major bleeding was not significantly different be tween enoxaparin and placebo in either group By multivariate regression analysis VIE risk in ambulatory patients was lower with enoxaparin vs placebo (odds ratio [OR] = 0 28,95% Cl 0 11-0 74 p=0 01) but higher in patients with a history of VIE (OR = 374, 95% Cl 1 59-8 84 p=0 003) or cancer (OR = 212, 95% Cl, 1 00-4 48, p=0 049) Despite timely mobilisation, patients who become ambulatory are at VTE risk and experience a significant risk reduction with enoxaparin 40 mg Therefore, it is essential that ambulatory patients receive recommended thromboprophylaxis