Kahlon P, Nabi S, Arshad A, Jabbar A, and Haythem A. Warfarin dosing and time required to reach therapeutic international normalized ratio in patients with hypercoagulable conditions. Turk J Haematol 2016; 33(4):299-303.
Turk J Haematol
OBJECTIVE: The purpose of this study was to analyze the difference in duration of anticoagulation and dose of warfarin required to reach a therapeutic international normalized ratio [(INR) of 2 to 3] in patients with hypercoagulable conditions as compared to controls. To our knowledge, this study is the first in the literature to delineate such a difference.
MATERIALS AND METHODS: A retrospective chart review was performed in a tertiary care hospital. The total study population was 622. Cases (n=125) were patients with a diagnosis of a hypercoagulable syndrome who developed venous thromboembolism. Controls (n=497) were patients with a diagnosis of venous thromboembolism in the absence of a hypercoagulable syndrome and were matched for age, sex, and race.
RESULTS: The total dose of warfarin required to reach therapeutic INR in cases was higher (50.7±17.6 mg) as compared to controls (41.2±17.7 mg). The total number of days required to reach therapeutic INR in cases was 8.9±3.5 days as compared to controls (6.8±2.9 days). Both of these differences were statistically significant (p<0.001).
CONCLUSION: Patients with hypercoagulable conditions require approximately 10 mg of additional total warfarin dose and also require, on average, 2 extra days to reach therapeutic INR as compared to controls.
Medical Subject Headings
Adult; Aged; Anticoagulants; Blood Coagulation; Case-Control Studies; Female; Humans; International Normalized Ratio; Male; Middle Aged; Odds Ratio; Retrospective Studies; Thrombophilia; Time Factors; Venous Thrombosis; Warfarin