Feasibility of venous thromboembolism prophylaxis during inflammatory bowel disease flares in the outpatient setting: A decision analysis

Background: Inflammatory bowel disease (IBD) patients are at increased risk of venous thromboembolism (VTE), which is most pronounced during a disease flare. We explored the cost-effectiveness of pharmacological VTE prophylaxis in an outpatient setting. Methods: Markov decision analysis was conducted from a societal perspective to compare the relative costs and effectiveness of pharmacological VTE prophylaxis versus no anticoagulation during ambulatory IBD flares among a hypothetical cohort of 10,000 IBD patients. The time horizon was from time of IBD diagnosis until death. Univariate and probabilistic sensitivity analyses were performed. Results: In base case analysis, VTE prophylaxis was, compared with no anticoagulation, associated with higher average costs (U.S. ≥141,036 versus ≥90,338) and quality-adjusted life-years (QALYs) (22.29 versus 22.25), yielding an incremental cost-effectiveness ratio of ≥1,267,450/QALY. Venous thromboembolism prophylaxis resulted in higher unadjusted life-years (47.76 life-years versus 46.67 life-years) and lower lifetime risk of VTE (6.2% versus 9.3%). The number needed to treat to prevent one VTE event over a lifetime was 32.3. Univariate sensitivity analysis showed that the incremental cost-effectiveness ratio was most sensitive to variations in the efficacy of VTE prophylaxis. In probabilistic sensitivity analysis, only 20% of 1000 simulated trials showed that VTE prophylaxis increased QALYs. In the remaining 80%, it was associated with both higher costs and fewer QALYs. Conclusions: Although the administration of pharmacological VTE prophylaxis during IBD flares in the outpatient setting was associated with increased life-years and reduced VTE events, it was not cost effective. Moreover, the benefits of VTE prophylaxis were not robust to probabilistic sensitivity analysis.