Cost-Benefit Limitations of Extended, Outpatient Venous Thromboembolism Prophylaxis following Surgery for Crohn's Disease

BACKGROUND: Patients with Crohn's disease are at increased risk of postoperative venous thromboembolism. Historically, extended outpatient prophylaxis has not met conventional measures of societal cost-benefit advantage. However, extended prophylaxis for patients with Crohn's disease may be more cost-effective because of the patients' high thrombotic risk and long life expectancy. OBJECTIVE: This study aimed to assess the cost-effectiveness of extended prophylaxis in patients with Crohn's disease after abdominal surgery. DESIGN: A decision tree model was used to assess the incremental cost-effectiveness and cost per case averted with extended-duration venous thromboembolism prophylaxis following abdominal surgery. SETTING: The risk of a postdischarge thrombotic event, age at surgery, type of thrombotic event, prophylaxis risk reduction, bleeding complications, and mortality were estimated by using existing published sources. PATIENTS: Studied were patients with Crohn's disease versus routine care. INTERVENTION: We constructed a decision analysis to compare costs and outcomes in patients with Crohn's disease postoperatively with and without extended prophylaxis over a lifetime horizon. MAIN OUTCOME MEASURES: Productivity costs ($) and benefits (quality-adjusted life-year) were used to reflect a societal perspective and were time discounted at 3%. Multivariable probabilistic sensitivity analysis accounted for uncertainty in probabilities, costs, and utility weights. RESULTS: With the use of reference parameters, the individual expected societal total cost of care was $399.83 without and $1387.95 with prophylaxis. Preventing a single mortality with prophylaxis would cost $43.00 million (number needed to treat: 39,839 individuals). The incremental cost was $1.90 million per quality-adjusted life-year. Adjusting across a range of scenarios upheld these conclusions 88% of the time. With further sensitivity testing, subpopulations with postdischarge thrombosis rates greater than 4.9% favors postoperative extended-duration venous thromboembolism prophylaxis. LIMITATIONS: Further investigation is needed to determine if specific high-risk individuals can be preemptively identified in the Crohn's surgical population for targeted prophylaxis. CONCLUSION: Extended prophylaxis in patients with Crohn's disease postoperatively is not cost-effective when the cumulative incidence of posthospital thrombosis remains less than 4.9%. These findings are driven by the low absolute risk of thrombosis in this population and the considerable cost of universal treatment.