Marc Schindewolf

Heparin-induced thrombocytopenia (HIT) is a life-threatening complication associated with high medical costs. Factor Xa inhibitors gradually replace approved treatment with intravenous direct thrombin inhibitors despite their off-label indication, because of easier management and favorable economic profile. Whether they are cost-effective remains unclear. We evaluated the cost-effectiveness of approved and off-label anticoagulants in patients with suspected HIT, based on census data from the largest Swiss hospital between 2015 and 2018. We constructed a decision tree model that reflects important clinical events associated with HIT. Relevant cost data were obtained from the finance department or estimated based on the Swiss-wide cost tariff. We estimated averted adverse events (AEs) and incremental cost-effectiveness ratio as primary outcome parameters. We performed deterministic and probabilistic sensitivity analyses with 2000 simulations to assess the robustness of our results. In the base-case analysis, the total cost of averting 1 AE was 49 565 Swiss francs (CHF) for argatroban, 30 380 CHF for fondaparinux, and 30 610 CHF for rivaroxaban; after adjusting for 4Ts score: 41 152 CHF (argatroban), 27 710 CHF (fondaparinux), and 37 699 CHF (rivaroxaban). Fondaparinux and rivaroxaban were more clinically effective than argatroban, with AEs averted of 0.820, 0.834, and 0.917 for argatroban, fondaparinux, and rivaroxaban, respectively. Treatment with fondaparinux resulted in less cost and more AEs averted, hence dominating argatroban. Results were most sensitive to AE rates and prolongation of stay. Monte Carlo simulations affirmed our base-case analysis. This is the first cost-effectiveness analysis comparing argatroban with fondaparinux and rivaroxaban using primary data. Fondaparinux and rivaroxaban resulted in more averted AEs, but fondaparinux had greater cost savings. Fondaparinux could be a viable alternative to argatroban.