Comparison of bleeding in patients with nonvalvular atrial fibrillation treated with ximelagatran or warfarin: assessment of incidence, case-fatality rate, time course and sites of bleeding, and risk factors for bleeding.
BACKGROUND
Ximelagatran is a novel direct thrombin inhibitor that can be administered as a fixed oral dose, without the need for anticoagulant monitoring.


METHODS
We undertook a pooled analysis of 7329 patients with nonvalvular atrial fibrillation from the Stroke Prevention Using Oral Thrombin Inhibitor in Atrial Fibrillation III and V trials to compare bleeding outcomes in patients who received ximelagatran, 36 mg twice daily, or warfarin sodium (target international normalized ratio, 2.0-3.0). We determined annual risk of bleeding (any, major), case-fatality rate, time course and anatomic sites of major bleeding, and risk factors for major bleeding with ximelagatran and warfarin treatment.


RESULTS
Annual incidence of any bleeding was 31.75% with ximelagatran and 38.82% with warfarin (relative risk reduction, 18.2%; 95% confidence interval [CI], 13.0-23.1; P<.001). Annual incidence of major bleeding was 2.01% with ximelagatran and 2.68% with warfarin (relative risk reduction, 25.1%; 95% CI, 3.2-42.1; P = .03). Case-fatality rate of bleeding was comparable in ximelagatran- and warfarin-treated patients (8.16% vs 8.09%; P = .98). Cumulative incidence of major bleeding was higher with warfarin than ximelagatran after 24 months of treatment (4.7% vs 3.7%; P = .04). Anatomic sites of bleeding were comparable with both treatments. Risk factors for bleeding with ximelagatran were as follows (hazard ratios and 95% CIs in parentheses): diabetes mellitus (1.81; 1.19-2.77; P = .006), previous stroke or transient ischemic attack (1.78; 1.16-2.73; P = .008), age 75 years or greater (1.70; 1.33-2.18; P<.001), and aspirin use (1.68; 1.08-2.59; P = .02). Risk factors for bleeding in warfarin-treated patients were previous liver disease (4.88; 1.55-15.39; P = .007); aspirin use (2.41; 1.69-3.43; P<.001); and age 75 years or greater (1.26; 1.03-1.52; P = .02).


CONCLUSIONS
Treatment with ximelagatran, 36 mg twice daily, is associated with a lower risk of bleeding than warfarin in patients with nonvalvular atrial fibrillation. Aspirin use and increasing age were associated with an increased risk of bleeding in ximelagatran- and warfarin-treated patients.
Douketis
James D
JD
Department of Medicine, McMaster University, Hamilton, Ontario, Canada. jdouket@mcmaster.ca
Arneklev
Karin
K
Goldhaber
Samuel Z
SZ
Spandorfer
John
J
Halperin
Frank
F
Horrow
Jay
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000150:complications / Q000188:drug therapy*; D001384:Azetidines / Q000008:administration & dosage / Q000627:therapeutic use*; D001596:Benzylamines / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000139:chemically induced / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D015996:Survival Rate; D013927:Thrombosis / Q000209:etiology / Q000517:prevention & control; D013997:Time Factors; D016896:Treatment Outcome; D014859:Warfarin / Q000009:adverse effects / Q000627:therapeutic use*
D000925:Anticoagulants; D001384:Azetidines; D001596:Benzylamines; C426686:ximelagatran; D014859:Warfarin