Cost-effectiveness analysis of extended thromboprophylaxis with rivaroxaban versus no prophylaxis in high-risk patients after hospitalisation for COVID-19: an economic modelling study.

Background: In patients at high risk of thromboembolism who were discharged after hospitalisation due to COVID-19, thromboprophylaxis with rivaroxaban 10 mg/day for 35 days significantly improved clinical outcomes, reducing thrombotic events compared with no post-discharge anticoagulation. The present study aimed to estimate the cost-effectiveness of this anticoagulation strategy.

Methods: Using the database of the MICHELLE trial, we developed a decision tree to estimate the cost-effectiveness of thromboprophylaxis with rivaroxaban 10 mg/day for 35 days versus no thromboprophylaxis in high-risk post-discharge patients for COVID-19 through an incremental cost-effectiveness analysis.

Findings: 318 patients in 14 centres in Brazil were enrolled in the primary MICHELLE trial. The mean age was 57.1 years (SD 15.2), 127 (40%) were women, 191 (60%) were men, and the mean body-mass index was 29.7 kg/m2 (SD 5.6). Rivaroxaban 10 mg per day orally for 35 days after discharge decreased the risk of events defined by the primary efficacy outcome by 67% (relative risk 0.33, 95% CI 0.12-0.90; p = 0.03). The mean cost for thromboprophylaxis with rivaroxaban was $53.37/patient, and no prophylaxis was $34.22/patient, with an incremental cost difference of $19.15. The effectiveness means obtained in the intervention group was 0.1457, while in the control group was 0.1421, determining an incremental QALY difference of 0.0036. The estimated incremental cost-effectiveness ratio (ICER) was $5385.52/QALY.

Interpretation: Extended treatment with Rivaroxaban as thromboprophylaxis after hospital discharge for high-risk patients with COVID-19 is a cost-effective treatment option.

Funding: Modest funding was provided by Science Valley Research Institute, São Paulo, Brazil.