Background: Enoxaparin 30 mg twice daily and dalteparin 5,000 units once daily are two common low-molecular-weight heparin (LMWH) thromboprophylaxis regimens used in the trauma population. Pharmacodynamic studies suggest that enoxaparin provides more potent anticoagulation than does dalteparin.
Methods: In 2009, our institution switched its formulary LMWH from enoxaparin to dalteparin followed by a switch back to enoxaparin in 2013. Using a difference in differences design, we contrasted the change in the VTE rate accompanying the LMWH switch with the change in a control group of trauma patients given unfractionated heparin (UFH) during the same period.
Results: The study included 5,880 patients: enoxaparin period (enoxaparin, n = 2,371; UFH, n = 1,539) vs the dalteparin period (dalteparin, n = 1,046; UFH, n = 924). The VTE rate was unchanged in the LMWH group: 3.3/1000 days in the enoxaparin period vs 3.8/1000 days in the dalteparin period: rate ratio (RR), 1.16; 95% CI 0.74-1.81. The rate was also unchanged in the UFH control subjects: 5.7/1,000 days in the enoxaparin period vs 5.2/1,000 days in the dalteparin period: RR, 0.92; 95% CI, 0.61-1.38. After confounding adjustment, the ratio of the change in VTE rate between the LMWH and UFH groups was similar: RR, 1.06; 95% CI 0.71-2.00. A secondary analysis excluding patients with delayed or interrupted prophylaxis (or both) altered this estimate nonsignificantly in favor of enoxaparin: RR, 2.39; 95% CI, 0.80-7.09.
Conclusions: Our results suggest that dalteparin has an effectiveness similar to that of enoxaparin in real-world trauma patients. Future research should investigate how the timing and consistency of prophylaxis affects LMWH effectiveness.
Keywords: VTE; comparative effectiveness; dalteparin; enoxaparin; prophylaxis; trauma.
Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.