De Ritis ratio as a significant prognostic factor of international normalized ratio ≥4 in the initial 10 days of warfarin therapy

Aim: To assess the relationship between the De Ritis ratio on admission and warfarin sensitivity in the initial 10 days of anticoagulation therapy. Methods: We retrospectively reviewed data from 906 patients who underwent heart valve replacement surgery. Results: A De Ritis ratio of 1.19 was identified as the optimal cutoff according to the ROC curve. Patients with a high De Ritis ratio achieved an international normalized ratio (INR) ≥4 more easily and earlier than those with a low De Ritis ratio in the initial 10 days of warfarin therapy. Multivariate analysis showed that a high De Ritis ratio was an independent predictor of an INR ≥4 (HR: 2.567; p < 0.001). Conclusion: A De Ritis ratio ≥1.19 on admission was significantly associated with an INR ≥4 in the initial 10 days of warfarin therapy among patients underwent heart valve replacement surgery.