Bleeding Risk Scores in Atrial Fibrillation: Helpful or Harmful?

T he prevalence of atrial fibrillation (AF) in the United States is 12% in ages 75 to 84 years of age and is expected to continue to rise. AF is known to increase the risk of stroke. Among patients with AF, stroke and thromboembolism risk is mitigated with the addition of anticoagulants. However, this is associated with increased risk of bleeding, specifically intracranial hemorrhage in the setting of warfarin. Because of this, prescribers are hesitant to anticoagulate, especially in the elderly population. There have been multiple risk stratification scoring systems utilized to assess bleeding risk including HAS-BLED (Hypertension, Abnormal renal and liver function, Stroke, Bleeding, Labile INR, Elderly, Drugs or alcohol), HEMORR2HAGES (History of bleeding, Hepatic or renal disease, Alcohol abuse, Malignancy, Older age, Reduced platelet count or function, Hypertension, Anemia, Genetic predisposition, Excessive fall risk, Stroke), ORBIT-AF (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation), and ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation) with the new addition of GARFIELD-AF (Global Anticoagulant Registry in the Field-Atrial Fibrillation). In the past, HAS-BLED bas been found to be superior at determining any clinically relevant bleeding risk by receiver-operating characteristic analysis and decision curve analysis (C index: HAS-BLED: 0.6 versus HEMORR2HAGES: 0.55 versus ATRIA: 0.50). However, more recently, the GARFIELD-AF risk model has been shown to be superior in major bleeding in comparison to HAS-BLED (C index: 0.66 GARFIELD-AF versus 0.64 HAS-BLED). Proietti and colleagues sought to challenge GARFIELD-AF’s superiority in this issue of the Journal of the American Heart Association (JAHA) and compared the predictive value of HAS-BLED with GARFIELD-AF risk model in the SPORTIF (Stroke Prevention Using the Oral Direct Thrombin Inhibitor Ximelagatran in Patients With Atrial Fibrillation Trial III and V) population. This study did show modest predictive value for major bleeding in both bleeding scores (C index: 0.58 HAS-BLED versus 0.56 GARFIELD-AF). The high-risk HAS-BLED score (>3) patients had higher risk of major bleeding, clinically relevant nonmajor bleeding, and any bleeding in comparison to low-risk HAS-BLED patients. In contrast, except for the major clinically relevant bleeding outcomes metric, the GARFIELD-AF score did not show a statistically significant difference for major bleeding and any bleeding in the high-risk patients comparedwith the low-risk patients. Lastly, therewas a net benefit of 5% of any bleeding with HAS-BLED in comparison to GARFIELD-AF. The authors concluded GARFIELD-AF was not superior to HAS-BLED, specifically in predicting any bleeding. The patient populations of these 2 studies were substantially different. First, the patients in the study by Lip and colleagues were from the SPORTIF III and V controlled clinical trials, a more constrained population with strict inclusion and exclusion factors. As expected, the time in the therapeutic range in these controlled patients was 68.2% compared with the time in the therapeutic range of patients in GARFIELD-AF, a real-world registry, of 55%. Additionally, the patients in the SPORTIF III and V cohorts were sicker compared with GARFIELD-AF. Eighty-nine percent of patients in SPORTIF III and V had chronic AF as compared with 12.7% in GARFIELD-AF. Further comparisons are shown in the Table. Even when externally validating the GARFIELD-AF risk model in the same study to the ORBIT-AF population, the predictive value fell (C index: 0.61). The authors postulate that this was because of the longer duration of AF in the ORBIT-AF population compared with GARFIELD-AF, again distinguishing it from the SPORTIF III and V population where the duration of AF was >1 year in 81% of the patients. Overall, both studies are valid, but, as one might expect, different risk scoring systems will have different results The opinions expressed in this article are not necessarily those of the editors or of the American Heart Association. From the MetroHealth System Campus, Case Western Reserve University, Cleveland, OH. Correspondence to: William R. Lewis, MD, MetroHealth System Campus, Heart and Vascular Center, Case Western Reserve University, Suite H-330, 2500 MetroHealth Dr, Cleveland, OH 44109. E-mail: wlewis@metrohealth.org J Am Heart Assoc. 2018;7:e010582. DOI: 10.1161/JAHA.118.010582. a 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.