752: EVALUATION OF RESPONSE TO HIGH-DOSE VITAMIN K ADMINISTRATION

Abstract

Introduction: Essential to the coagulation pathway, vitamin K is used to correct clotting factor deficiencies and for reversal of warfarin-induced bleeding. In practice, and particularly for cirrhosis-associated coagulopathy, high-dose IV vitamin K is often given on consecutive days despite limited evidence to support repeated dosing and potential risks with parenteral administration. This study sought to characterize differences in responders and non-responders to high-dose vitamin K to better guide dosing strategies in patients with coagulopathy. Methods: This was a case-control study of hospitalized adults (≥18 years) who received vitamin K 10 mg IV daily for three days for treatment of coagulopathy, defined as an international normalized ratio (INR) of greater than 1.5. Patients with an INR < 1.5 or ≥30% lower than baseline following the first dose of vitamin K were considered responders and compared to non-responders. The primary outcome was the change in INR over time with subsequent IV vitamin K doses. A linear mixed-effects model (LMM) compared the reduction of INR on follow-up time points between groups. Secondary outcomes included factors associated with response to IV vitamin K and the incidence of safety events. Results: There were 497 patients included in this study, and 182 patients responded to the first dose of IV vitamin K. Most patients were white males (73%) with a mean age of 54 ± 15 years. Most patients had underlying cirrhosis (91.5%), with a MELD score of 23.9 ± 10.6. The INR decreased from 1.87 (adjusted least square mean from LMM, 95% CI 1.73-2.03) to 1.61 (95% CI 1.49-1.74), which was a 16.5% reduction from baseline to day 3 (95% CI 12.6%-20.5%). In responders, the INR decreased from 1.89 at baseline (95% CI 1.74-2.04) to 1.40 (1.3-1.5) on day 3 (95% CI 1.30-1.50). In non-responders, the INR decreased from 1.97 at baseline (95% CI 1.83-2.13) to 1.85 on day 3 (95% CI 1.72-1.99). Predictors of response included lower weight, absence of cirrhosis, and lower bilirubin. There was a low incidence of safety events observed in this study. Conclusions: In this cohort of which the majority were patients with cirrhosis, the overall adjusted change in INR over 3 days was 0.3, which didn’t vary much clinically between responders and non-responders.