Hip surgery patients are at highest risk of any surgical patients for the development of deep vein thrombosis. Therefore, finding ways to prevent these blood clots is a major concern among doctors. Dangerous blood clots that develop after hip surgery may be reduced by 96% when people receive treatment with a new blood thinner.

The study was led by Bengt I. Eriksson, MD, PhD (Sahlgrenska University Hospital/Östra, Göteborg, Sweden) and Michael R. Lassen, MD (University Hospital of Copenhagen Hillerød, Hillerød, Denmark).

Study Set-Up
Six hundred and fifty patients who were undergoing surgery for hip fracture took part. Half received daily injections of the drug fondaparinux for between 19 and 23 days; the other half received daily injections of a placebo (an inactive substance or preparation used as a control in an experiment or test to determine the effectiveness of a medicinal drug). All participants had received six to eight days of treatment with fondaparinux prior to beginning the study.

Findings
Researchers were able to measure outcomes in 428 of the 650 patients. Fondaparinux reduced the incidence of postoperative venous thromboembolism (VTE) compared with placebo from 35.0% (77/220) to 1.4% (3/208), with a relative reduction in risk of 95.9%.

Similarly, the incidence of symptomatic VTE was significantly lower with fondaparinux (1/326; 0.3%) than with placebo (9/330; 2.7%). The relative reduction in risk was 88.8% .

Although there was a trend toward more major bleeding in the fondaparinux group than in the placebo group, there were no differences between the two groups in the incidence of clinically relevant bleeding (leading to death, reoperation, or critical organ bleeding).

Conclusions
Researchers suggest that extended prophylaxis with fondaparinux for three weeks after hip fracture surgery reduced the risk of VTE by 96% and was well tolerated.

Furthermore, they believe their study population is representative of patients undergoing hip fracture surgery in clinical practice and that these beneficial results can be reproduced in a routine setting.

Sources: - Duration of prophylaxis against venous thromboembolism with fondaparinux after hip fracture surgery. Archives of Internal Medicine, 2003; 163: 1337-1342 - www.ivanhoe.com