The ORBIT Bleeding Score: A Simple Bedside Score to Assess Bleeding Risk in Atrial Fibrillation

Emily C. O'Brien; DaJuanicia N. Simon; Laine E. Thomas; Elaine M. Hylek; Bernard J. Gersh; Jack E. Ansell; Peter R. Kowey; Kenneth W. Mahaffey; Paul Chang; Gregg C. Fonarow; Michael J. Pencina; Jonathan P. Piccini; Eric D. Peterson

Disclosures

Eur Heart J. 2015;36(46):3258-3264. 

In This Article

Abstract and Introduction

Abstract

Background Therapeutic decisions in atrial fibrillation (AF) are often influenced by assessment of bleeding risk. However, existing bleeding risk scores have limitations.

Objectives We sought to develop and validate a novel bleeding risk score using routinely available clinical information to predict major bleeding in a large, community-based AF population.

Methods We analysed data from Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF), a prospective registry that enrolled incident and prevalent AF patients at 176 US sites. Using Cox proportional hazards regression, we identified factors independently associated with major bleeding among patients taking oral anticoagulation (OAC) over a median follow-up of 2 years (interquartile range = 1.6–2.5). We also created a numerical bedside risk score that included the five most predictive risk factors weighted according to their strength of association with major bleeding. The predictive performance of the full model, the simple five-item score, and two existing risk scores (hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile INR, elderly, drugs/alcohol concomitantly, HAS-BLED, and anticoagulation and risk factors in atrial fibrillation, ATRIA) were then assessed in both the ORBIT-AF cohort and a separate clinical trial population, Rivaroxaban Once-daily oral direct factor Xa inhibition compared with vitamin K antagonism for prevention of stroke and embolism trial in atrial fibrillation (ROCKET-AF).

Results Among 7411 ORBIT-AF patients taking OAC, the rate of major bleeding was 4.0/100 person-years. The full continuous model (12 variables) and five-factor ORBIT risk score (older age [75+ years], reduced haemoglobin/haematocrit/history of anaemia, bleeding history, insufficient kidney function, and treatment with antiplatelet) both had good ability to identify those who bled vs. not (C-index 0.69 and 0.67, respectively). These scores both had similar discrimination, but markedly better calibration when compared with the HAS-BLED and ATRIA scores in an external validation population from the ROCKET-AF trial.

Conclusions The five-element ORBIT bleeding risk score had better ability to predict major bleeding in AF patients when compared with HAS-BLED and ATRIA risk scores. The ORBIT risk score can provide a simple, easily remembered tool to support clinical decision making.

Introduction

Anticoagulation therapy can clearly reduce the risk of stroke and systemic emboli when used in atrial fibrillation (AF) patients,[1,2] yet clinicians and patients must often consider these benefits vs. the risk of major bleeding.[3,4] In clinical practice, simple scores can serve as a useful tool to support providers to estimate the risks of stroke as well as for major bleeding.[5–8] However, existing bleeding scores, including hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile INR, elderly, drugs/alcohol concomitantly (HAS-BLED)[9] and anticoagulation and risk factors in atrial fibrillation (ATRIA),[10] were based on small numbers of events,[11] have shown inconsistent performance in external populations,[12,13] and may require data elements that are not accessible for all oral anticoagulation (OAC) users.[14–16] Therefore, there remains a need for a simple, accurate risk score that uses readily available clinical information to predict the occurrence of major bleeding in AF patients receiving contemporary anticoagulation.

Using data from the national Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) registry, we constructed a full continuous predictive model as well as a simple risk score for major bleeding among patients who were taking OAC therapy. We compared the performance of this novel score to that of two other major bleeding models (HAS-BLED and ATRIA) in the ORBIT-AF population as well as in an external validation sample of those enrolled in Rivaroxaban Once-daily oral direct factor Xa inhibition compared with vitamin K antagonism for prevention of stroke and embolism trial in atrial fibrillation (ROCKET-AF), a randomized trial of anticoagulation therapy for stroke prevention.

Comments

3090D553-9492-4563-8681-AD288FA52ACE

processing....