Bleeding Risk and Antithrombotic Strategy in Patients With Sinus Rhythm and Heart Failure With Reduced Ejection Fraction Treated With Warfarin or Aspirin

Abstract

We sought to assess the performance of existing bleeding risk scores, such as the Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile INR, Elderly, Drugs/Alcohol Concomitantly (HAS-BLED) score or the Outpatient Bleeding Risk Index (OBRI), in patients with heart failure with reduced ejection fraction (HFrEF) in sinus rhythm (SR) treated with warfarin or aspirin. We calculated HAS-BLED and OBRI risk scores for 2,305 patients with HFrEF in SR enrolled in the Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction trial. Proportional hazards models were used to test whether each score predicted major bleeding, and comparison of different risk scores was performed using Harell C-statistic and net reclassification improvement index. For the warfarin arm, both scores predicted bleeding risk, with OBRI having significantly greater C-statistic (0.72 vs 0.61; p = 0.03) compared to HAS-BLED, although the net reclassification improvement for comparing OBRI to HAS-BLED was not significant (0.32, 95% confidence interval [CI] -0.18 to 0.37). Performance of the OBRI and HAS-BLED risk scores was similar for the aspirin arm. For participants with OBRI scores of 0 to 1, warfarin compared with aspirin reduced ischemic stroke (hazard ratio [HR] 0.51, 95% CI 0.26 to 0.98, p = 0.042) without significantly increasing major bleeding (HR 1.24, 95% CI 0.66 to 2.30, p = 0.51). For those with OBRI score of ≥2, there was a trend for reduced ischemic stroke with warfarin compared to aspirin (HR 0.56, 95% CI 0.27 to 1.15, p = 0.12), but major bleeding was increased (HR 4.04, 95% CI 1.99 to 8.22, p <0.001). In conclusion, existing bleeding risk scores can identify bleeding risk in patients with HFrEF in SR and could be tested for potentially identifying patients with a favorable risk/benefit profile for antithrombotic therapy with warfarin.

Figure 1. Proportion of patients with major bleedings, by HAS-BLED and OBRI risk scores and by treatment arm

P-values for trend were calculated using Cox proportional hazards models.

Figure 2. The effect of warfarin versus aspirin on clinical outcomes for subgroups of WARCEF participants stratified by OBRI and HAS-BLED risk scores

P-values represent results of tests of interaction between treatment assignment and bleeding risk subgroups identified by OBRI and HAS-BLED risk score.