Cost effectiveness of a low-molecular-weight heparin in prolonged prophylaxis against deep vein thrombosis after total hip replacement

The risk of late-occurring deep vein thrombosis and pulmonary embolism after total hip replacement persists for at least 3 weeks after hospital discharge. Recent clinical trials have demonstrated that prolonged prophylaxis with enoxaparin, a low-molecular-weight heparin (LMWH), significantly reduces this risk. We used a decision-analysis model to determine the incremental outcomes associated with the routine use of such prophylaxis, administered during hospitalisation for total hip replacement and for 3 weeks after discharge, instead of short term prophylaxis administered only during hospitalisation. For a hypothetical cohort of 100 000 patients undergoing hip surgery, prolonged LMWH prophylaxis saved between 601 and 783 additional lives compared with prophylaxis stopped at discharge. This was obtained at a net direct marginal cost ranging from 1118 to 1300 French francs (F) per patient. The cost-effectiveness ratio ranged from F11 158 to F34 591 per life-year saved and from F23 532 to F35 268 per venous thromboembolic event (routinely diagnosed and treated) avoided. Prolonged LMWH anticoagulant prophylaxis with enoxaparin is more effective in routine practice after elective hip surgery than conventional short term perioperative prophylaxis in terms of the number of deaths or thromboembolic events avoided. Such prophylaxis also appears to be clearly cost effective, using French cost data.