Aspinall SL (VA Pittsburgh Healthcare System)
DeSanzo BE (Butler VA Medical Center)
Trilli LE (VA Pittsburgh Healthcare System)
Good CB (VA Pittsburgh Healthcare System)
To determine the usefulness of the Outpatient Bleeding Risk Index in a Veterans Affairs Anticoagulation Clinic and to evaluate its utility in patients with atrial fibrillation.
We retrospectively applied the Outpatient Bleeding Risk Index (BRI) to patients enrolled in our clinic before 2001 and prospectively applied it to new patients between January 1, 2001 and December 31, 2002. As per the BRI, we assigned patients one point for each of the following risk factors: (1) age >= 65 years, (2) history of stroke, (3) history of gastrointestinal bleed, and (4) recent myocardial infarction, hematocrit <30%, serum creatinine >1.5mg/dl, or diabetes mellitus. Based on their total number of points, patients were classified as low- (0 points), intermediate- (1 or 2 points), or high-risk (3 or 4 points) for major bleeding. Major bleeds were identified via routine quality assurance reports for calendar years 2001 and 2002. Finally, using the administrative database for the clinic, we collected the indication for warfarin. Poisson regression was used to determine whether there was an association between the risk level and major bleeding.
There were 1308 patient-years of warfarin therapy for those in clinic between January 1, 2001 and December 31, 2002. Atrial fibrillation was the most common indication (556 patients-years), and most patients were in the intermediate-risk group (997 patient-years). The major bleeding rate was 10.6%, 2.5%, and 0.8% per patient-year of warfarin in the high-, intermediate-, and low-risk groups, respectively. Incidence rate ratios (95% CI) for major bleeding compared with the low-risk group were 3.31 (0.45, 24.43) for the intermediate- and 14.01 (1.88, 104.66) for the high-risk group. The rates were significantly different between the high- and intermediate-risk categories (p<0.001). Among those with atrial fibrillation, patients in the high-risk category had approximately six times the major bleeding rate of those in the other groups combined (IRR=6.04; 95% CI 2.39, 15.31).
The Outpatient Bleeding Risk Index discriminates between high- and intermediate-risk patients in a Veterans Affairs anticoagulation clinic.
The simple use of the Outpatient Bleeding Risk Index can help providers objectively quantify the risk for major hemorrhage with warfarin therapy.