Venous thromboembolism (VTE) is a major cause of morbidity and mortality in hospitalized patients. A large international study in acutely ill medical patients assessed the efficacy of the low-molecular-weight heparin dalteparin for prevention of clinically important VTE. We undertook a subanalysis of the study to assess the benefit of thromboprophylaxis in the patients with respiratory failure.
PREVENT was a randomized, double-blind, placebo-controlled trial in hospitalized medical patients at moderately high risk of VTE. Patients received dalteparin (5000 IU QD) or placebo, for 14 days. The primary endpoint was clinically important VTE, defined as objectively verified symptomatic deep vein thrombosis (DVT), pulmonary embolism (PE), sudden death, and objectively verified asymptomatic proximal DVT. Compression ultrasound was performed in all patients who had not reached an endpoint by day 21.
3706 patients were enrolled at 219 centers in 26 countries. The incidence of the composite primary outcome was 2.77% in the dalteparin group and 4.96% in the placebo group, a risk reduction of 45% (95% CI, 20%-62%) [P=0.0015]. Major bleeding occurred in 12 patients, 9 (0.49%) receiving dalteparin and 3 (0.16%) placebo (n.s.) Among the 877 patients admitted with acute respiratory failure not requiring ventilatory support, the primary endpoint incidence was 3.62% (16/442) in the dalteparin group and 5.06% (22/435) in the placebo group, a 28% risk reduction (95% CI, −34% to 62%). In the 947 patients with acute or chronic respiratory failure treated with dalteparin vs placebo the incidence was 3.36% vs 5.10% respectively, a risk reduction of 34% (95% CI, −23% to 65%).CONCLUSIONS: Dalteparin 5000 IU daily reduces clinically important VTE in acutely ill medical patients, including those with respiratory failure, with a low risk of bleeding.
More widespread, routine thromboprophylaxis of medically ill patients should reduce the incidence of clinically important VTE and improve outcomes.
A.T. Cohen, Pharmacia, Grant monies,, Discussion of product research or unlabeled uses of product; Guy’s, King’s and St Thomas’ School of Medicine, University monies. Grant in respect of Steering Committee Consultancy