Velmahos GC, Oh Y, McCombs J, Oder D.
An evidence-based cost-effectiveness model on methods of prevention of
posttraumatic venous thromboembolism.
J Trauma 2000 Dec;49(6):1059-64

Department of Surgery, Keck School of Medicine, University of Southern
California, Los Angeles 90033, USA. velmahos@hsc.usc.edu

BACKGROUND: Venous thromboembolism (VT) after injury is a major health problem.
Literature data on methods of VT prophylaxis are not consistent with regard to
safety and efficacy, and a recent evidence-based report could not conclude that
any method was superior to any other or to no prophylaxis. Because no study
exists on the cost-effectiveness (C-E) of the different methods of prophylaxis,
data from the evidence-based report were used to design a C-E analysis. This
analysis will assist in the design of future randomized trials with adequate
power to show significant outcome differences. METHODS: A decision-tree model was
designed on the basis of outcomes from the evidence-based report or relevant
literature. We then calculated the cost of prevention of VT by one of the most
commonly used methods-low-dose heparin (LDH), low-molecular-weight heparin
(LMWH), or sequential compression devices (SCDs)-using different probabilities of
incidence of VT. Finally, we adjusted the cost for expected years of life after
the episode of VT to calculate the cost per life-year saved by preventing VT.
RESULTS: We produced two tables that can be used to calculate the cost per
life-year saved for any patient according to his or her age and the method of
prophylaxis used. VT prophylaxis becomes less cost-effective as age progresses,
because of decreased life-expectancy. With a widely accepted cost limit of
$50,000 per life-year saved to indicate cost-effective treatment, LDH is more
cost-effective than LMWH or SCDs. CONCLUSION: Our C-E model can help future
investigators plan VT-related research with appropriate sample sizes to evaluate
cost-effective methods of prophylaxis. LMWH and SCDs must demonstrate substantial
improvements in measured outcomes to be more cost-effective than LDH. C-E must be
incorporated as a primary outcome in future studies comparing different methods
of VT prophylaxis.