Deep vein thrombosis: prophylaxis: LMWH and warfarin were equally cost-effective in patients undergoing hip or knee replacement.

Clinical bottom line (level 1b)

  1. Low molecular weight heparin and warfarin were equally cost-effective in preventing deep vein thrombosis in patients undergoing total hip or knee replacement.
  2. The final decision depends on local drug costs, and the cost of monitoring warfarin therapy and treating bleeds.
Hull et al: Archives of Internal Medicine 1997; 157: 298-303
Expires May 2003

The study

cost-effectiveness analysis
Setting: teaching hospitals, USA and Canada

multicentre randomised trial of low molecular weight heparin versus warfarin in patients undergoing total knee or hip replacement

  • Viewpoint: third party, eg. HMO or NHS purchaser
  • Benefit assessment: occurrence of deep vein thrombosis
  • Resources and costs: actual costs for hospitals participating in the trial- drug treatment and cost of diagnosis and treatment if DVT was present, and treatment of complications
  • Sensitivity analysis: varied cost of treatment, monitoring, complications for both USA and Canada

    • The evidence

    intervention cost
    warfarin $116 (Canadian) per person
    ( DVT 37% )
    low molecular weight heparin $92 (Canadian) per person- saving $24
    ( DVT 31% )
    warfarin $209 (US) per person- saving $48
    ( DVT 37% )
    low molecular weight heparin $256 (US) per person
    ( DVT 31% )

    Effect of sensitivity analysis: Outcome varied depending on cost of drug, monitoring and treatment of bleeding.

    Comments

    1. In the USA, if the cost of low molecular weight heparin fell by 87.5% (ie. $6 to $0.75) then both treatments would be equally cost-effective. This is unlikely to occur in the near future.
    2. Hospitals and payers will make the choice based primarily on the cost of tinzaparin, and the cost of laboratory monitoring of INRs in their own institutions.

    Citation

    1. Hull RD, Raskob G, Pineo GF, et al: Low-molecular-weight heparin vs warfarin for prophylaxis of deep vein thrombosis after hip or knee implantation: an economic perspective. Archives of Internal Medicine 1997; 157: 298-303
    Contributor: Chris Ball and Clare Wotton, May 2000
    Reviewer: Edward Etchells

    Clinical Question.
    Patient undergoing knee or hip replacement
    Intervention or Exposure low molecular weight heparin
    Comparison warfarin
    Outcome cost-effectiveness