Screening and prevention of venous thromboembolism in critically ill patients: a decision analysis and economic evaluation.

RATIONALE

Venous thromboembolism is difficult to diagnose in critically ill patients and may increase morbidity and mortality.

OBJECTIVES

To evaluate the cost-effectiveness of strategies to reduce morbidity from venous thromboembolism in critically ill patients.

METHODS

A Markov decision analytic model to compare weekly compression ultrasound screening (screening) plus investigation for clinically suspected deep vein thrombosis (DVT) (case finding) versus case finding alone; and a hypothetical program to increase adherence to DVT prevention. Probabilities were derived from a systematic review of venous thromboembolism in medical-surgical intensive care unit patients. Costs (in 2010 $US) were obtained from hospitals in Canada, Australia, and the United States, and the medical literature. Analyses were conducted from a societal perspective over a lifetime horizon. Outcomes included costs, quality-adjusted life-years (QALY), and incremental cost-effectiveness ratios.

MEASUREMENTS AND MAIN RESULTS

In the base case, the rate of proximal DVT was 85 per 1,000 patients. Screening resulted in three fewer pulmonary emboli than case-finding alone but also two additional bleeding episodes, and cost $223,801 per QALY gained. In sensitivity analyses, screening cost less than $50,000 per QALY only if the probability of proximal DVT increased from a baseline of 8.5-16%. By comparison, increasing adherence to appropriate pharmacologic thromboprophylaxis by 10% resulted in 16 fewer DVTs, one fewer pulmonary emboli, and one additional heparin-induced thrombocytopenia and bleeding event, and cost $27,953 per QALY gained. Programs achieving increased adherence to best-practice venous thromboembolism prevention were cost-effective over a wide range of program costs and were robust in probabilistic sensitivity analyses.

CONCLUSIONS

Appropriate prophylaxis provides better value in terms of costs and health gains than routine screening for DVT. Resources should be targeted at optimizing thromboprophylaxis.