Atrial fibrillation (AF) commonly increases the risk of stroke. Among patients with AF, stroke and thromboembolism risk are mitigated by the addition of anticoagulants. However, this intervention may be associated with increased risk of bleeding including life-threatening intracranial hemorrhage. This complication may introduce an element of hesitancy to anticoagulate patients, in particular, those with underlying medical co-morbidities. Multiple risk stratification scoring systems have been utilized to assess bleeding risk, including HAS‐BLED, HEMORR2HAGES, ORBIT‐AF, and ATRIA. VTE-BLEED is a simple bleeding risk score that predicts the likelihood of major bleeding (MB) in patients with venous thromboembolism (VTE). More specifically, the VTE-BLEED score identifies 6 differently weighted variables (active cancer [2 points], men with uncontrolled hypertension [1 point], anemia [1.5 points], history of bleeding [1.5 points], age ≥60 years [1.5 points], and renal dysfunction [1.5 points]) as predictors of MB in patients with VTE receiving either warfarin or dabigatran. However, VTE-BLEED has never been evaluated in AF. To explore this further, Dr. Gordon Chu and colleagues sought to assess whether dabigatran dose reduction in VTE-BLEED “high-risk” patients resulted in a lower incidence of MB and the composite endpoint of MB plus stroke/systemic embolism.
Investigators examined the RE-LY trial that compared dabigatran to warfarin in this setting, and calculated the VTE-BLEED scores from 18,040 patients within this cohort. The AF-adapted VTE-BLEED score classified 4060 patients (22.5%), treated with dabigatran 150 mg BID or 110 mg BID, as high-risk. The composite outcome (death, major bleeding and stroke/systemic embolism) within the first 180 days was observed in 3.0% in patients on dabigatran 110 mg and 5.6% in patients on dabigatran 150 mg, corresponding to a hazard ratio of 0.53 (95% CI 0.35 – 0.79). Specific to the AF-adapted VTE-BLEED high-risk patients, the risk ratio between the 2 dabigatran doses was 0.53 (95% CI 0.36-0.79) for the composite outcome, in favor of dabigatran 110 mg BID. Application of AF-adapted VTE-BLEED (used to better suit the AF population resulting in two changes: age criterion to 75 and high-risk threshold >3) would therefore have led to a dosage change in 13% of patients on dabigatran. As Dr. Chu stated, “AF-adapted VTE-BLEED score predicted major bleeding in AF patients included in the RE-LY trial. In AF-adapted VTE-BLEED high-risk patients, those treated with the 110 mg twice daily dose had a lower incidence of the composite outcome (decreased bleeding events) compared to those treated with 150 mg twice daily. Only a fraction of those patients who may benefit from a reduced dose of dabigatran are currently identified by the current prescribing label. While promising, these findings should be confirmed in future studies, as VTE-BLEED had not been validated for AF previously.”