To the Editor.—
With regard to the article entitled "A Cost-effectiveness Analysis of Prophylaxis Against Deep-Vein Thrombosis in Major Orthopedic Surgery" by Oster et al,1 a few comments are offered. The cost-effectiveness of 5000IU of heparin sodium and 0.5 mg of dihydroergotamine mesylate (HDHE) was based on its administration twice daily for seven days. The authors estimated the likelihood of deep-vein thrombosis (DVT) from four studies2-5 in which HDHE was compared with low-dose heparin prophylaxis in patients undergoing orthopedic hip surgery (total number, 199). Three of the four studies2-4 used HDHE every eight hours and not twice daily. One of the studies2 was a continuance of another3 and shared 25 patients. Thus, the estimated DVT incidence was not based on four distinct patient populations. Furthermore, three of the four studies2,3,5 continued prophylaxis for at least ten days and the other4 for 15 days.
Emory CE. Prophylaxis for Deep-Vein Thrombosis. JAMA. 1987;257(17):2290-2291. doi:10.1001/jama.1987.03390170046016