I have read with great interest the article of Eriksson and Lassen regarding postdischarge thromboprophylaxis in patients who have undergone hip fracture surgery.1 However, the rationale of their assumptions of the venous thromboembolism (VTE) rate at day 28 in the 4-week fondaparinux group is not clear. What is the rationale to take a 1.4-fold increase of the VTE incidence at day 7, resulting in an expected deep vein thrombosis (DVT) rate of 11.4% at day 28, as the basis of the sample size calculation? The observed DVT incidence at day 28 of 1.3% in the 4-week fondaparinux group indicates that this assumption was incorrect.
Nurmohamed MT. Fondaparinux and Prolonged Thromboprophylaxis After Hip Fracture Surgery. Arch Intern Med. 2003;163(22):2789. doi:10.1001/archinte.163.22.2789