Vitamin K versus warfarin interruption alone in patients without bleeding and an international normalized ratio > 10

Abstract

BackgroundReversal of an international normalized ratio (INR) > 10 with vitamin K is recommended in patients experiencing bleeding; however, information on outcomes with reversal using vitamin K in non‐bleeding patients is lacking. ObjectiveTo compare clinical and safety outcomes between non‐bleeding patients receiving warfarin with an INR > 10 who did and did not receive a prescription for vitamin K. Patients/MethodsThis was a retrospective cohort study conducted in an integrated health‐care delivery system. Adult patients receiving warfarin therapy who experienced an INR > 10 without bleeding between 01/01/2006 and 06/30/2018 were included. Patients were assessed for an outpatient dispensing or in‐office administration of vitamin K on the day of or the day after an INR > 10 and then clinically relevant bleeding, thromboembolism, all‐cause mortality, and time to INR < 4 within the next 30 days. ResultsA total of 809 patients was included with 332 and 477 who were and were not dispensed vitamin K, respectively. Overall, mean patient age was 71.7 years, 60.1% were female and the mean INR was 10.4 at presentation. There were no differences between groups in 30‐day rates of bleeding or thromboembolism (both P > .05). Patients dispensed vitamin K had a higher likelihood of mortality (15.1% versus 10.1%, P = .032, adjusted odds ratio = 1.63, 95% confidence interval 1.03 to 2.57). Overall, time to an INR < 4 was similar between groups. ConclusionVitamin K administration was not associated with improved clinical outcomes in asymptomatic patients with an INR > 10.