The risk of hemorrhage among patients with warfarin-associated coagulopathy.
OBJECTIVE
Among warfarin-treated patients with international normalized ratio (INR) >5, we sought to determine the risk of major bleeding within 30 days.


BACKGROUND
For warfarin-treated patients, the risk of bleeding increases as the INR rises, particularly if the INR exceeds 4. The 30-day risk of hemorrhage among outpatients with excessively prolonged INR values is unknown.


METHODS
To assess anticoagulation care in the U.S., a cohort of 6,761 patients taking warfarin was prospectively assembled from 101 participating sites (43% were community-based cardiology practices). From this cohort, 1,104 patients were identified with a first episode of INR >5.


RESULTS
A total of 979 met eligibility criteria; complete follow-up information was available for 976 (99.7%). Ninety-six percent (n = 937) of patients had an INR value between 5 and 9; 80% of INR values were <7. Thirteen patients (1.3%) experienced major hemorrhage during the 30-day follow-up period; among patients whose INR was >5 and <9, 0.96% experienced major hemorrhage. None of the bleeding events was fatal. Intervention with vitamin K was uncommon (8.7%). Warfarin doses were withheld for the majority of patients. Fifty percent of patients who were managed conservatively and retested on day 4 or 5 had an INR of 2.0 or less.


CONCLUSIONS
For warfarin-treated outpatients presenting with an INR >5 and <9, the 30-day risk of major bleeding is low (0.96%). Intervention with vitamin K among asymptomatic patients presenting with an INR <9 is not routine practice in the U.S.
Department of Medicine, University of New Mexico, Albuquerque, New Mexico, USA. davgarcia@salud.unm.edu
David A
DA
Garcia
Susan
S
Regan
Mark
M
Crowther
Elaine M
EM
Hylek
D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects*; D005260:Female; D006470:Hemorrhage / Q000139:chemically induced* / Q000517:prevention & control; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D012306:Risk; D014812:Vitamin K / Q000627:therapeutic use; D014859:Warfarin / Q000009:adverse effects*
D000925:Anticoagulants; D014812:Vitamin K; D014859:Warfarin