Cost-Effectiveness of Venous Thromboembolism Prophylaxis after Total Hip Replacement

Abstract

Objective: To determine the cost-effectiveness of three strategies used for the prevention of venous thromboem-bolism (VTE) in patients undergoing total hip replace-ment (THR), and to perform a sensitivity analysis comparing VTE rates based on different methods of detection. Methods: In this cost-effectiveness analysis, three strategies of prophylaxis of postoperative VTE and THR were compared: (1) low-molecular-weight heparin (LMWH); Enoxaparin, (2) warfarin and (3) a combination of warfarin, heparin (UFH), graduated stockings and sequential long-leg pneumatic compression devices. The model estimates were based on pooled data from the published literature and from personal data in our series of hip replacement patients. Expected direct costs of VTE care, including prophylaxis, diagnosis and manage-ment of thromboembolic and hemorrhagic complications, were estimated for a hypothetical cohort of 100 patients in 2001 US dollars from data available for patients hospitalized at Evanston Northwestern Health-care. A sensitivity analysis was performed with different rates of VTE based on routine venography, routine duplex ultrasound, or selective diagnosis and treatment of symptomatic patients. Results: When venography was used to diagnose VTE, the cost of warfarin or LMWH treatment was $118 422 and $104 732 per 100 patients, respectively, providing cost savings of $ 13 690 per hundred patients for LMWH. When VTE rates were based on duplex ultrasound diagnoses, LMWH resulted in cost savings of $4602 and $1345 per 100 patients compared with the use of warfarin or the combined approach, respectively. However, when the rates of VTE were based on confirmed symptomatic cases, the use of LMWH resulted in an increased cost of $4486 and $10015 per 100 patients compared with warfarin and the combined approach, respectively. Conclusions: The use of LMWH for the prevention of VTE after THR was more cost-effective than using warfarin or the combined approach, when the VTE rate was based on routine venography or duplex ultrasound. However, the combined approach was more cost-effective than the use of warfarin or LMWH alone when only patients with confirmed, symptomatic VTE were treated.