Low molecular weight versus unfractionated heparin. A clinical and economic appraisal.

Unfractionated heparin (UFH) has been in clinical use for over 50 years and extensive clinical trials have demonstrated its effectiveness in the prevention and treatment of thrombotic disease. In the last 2 decades, low molecular weight heparins (LMWHs) have been developed and subjected to extensive laboratory and clinical studies. In clinical comparison with UFH in the treatment of venous thromboembolism, LMWHs appear to offer a superior benefit-risk profile. In addition, the ease of drug administration and lack of drug monitoring associated with LMWHs are attractive clinical features. We calculated the overall costs of UFH and LMWH therapy using recently published clinical data and local cost information. Although the acquisition costs of LMWHs are higher than for UFH, LMWHs are more cost effective in surgical prophylaxis of deep venous thrombosis (DVT) if the costs of failed prophylaxis are considered. The costs of using subcutaneous (SC) LMWH as therapy for established DVT are lower than those of UFH administered by intravenous infusion. The financial benefit of using LMWH treatment becomes more pronounced when the rates of antithrombotic failure and bleeding complications are incorporated. If UFH is given by SC injection, however, the cost differential favouring LMWH for the treatment of DVT is not so great. If current trials demonstrate that LMWH treatment can be given on an ambulatory outpatient basis, the economic advantages of LMWH will be considerable. However, the extent of this will vary from place to place depending on local funding arrangements.