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ATRIA Bleeding Risk Score

Calculators  Cardiovascular
The AnTicoagulation and Risk factors In Atrial fibrillation (ATRIA) bleeding risk score is used to determine the chance of bleeding in a patient taking warfarin as a anticoagulant for his/her atrial fibrillation.
Hemoglobin levels <12 g/dL (Female), <13 g/dL (Male)
No 0
Yes 3
Intense Renal Disease
Glomerular filtration rate <30 mL/min or dialysis-dependent
No 0
Yes 3
Age ≥75 years
No 0
Yes 2
Any Previous Hemorrhage Diagnosis
Ex: Intracranial hemorrhage, GI bleed
No 0
Yes 1
History of Hypertension
No 0
Yes 1


Measured Factor
ATRIA bleeding risk score
Measured Factor Disease
  • intracranial hemorrhage
  • extracranial hemorrhage
Measured Factor Detail
Bleeding associated with the use of anticoagulants such as warfarin can have significant impacts on health, and may be life threatening in some cases. Intracranial hemmorhage is one of the most significant concerns when patients are taking anticoagulant therapy. This calculator estimates hemorrhage risk to guide decision regarding warfarin use for atrial fibrillation. The hemorrhage risk is greater when patient has anemia, severe renal disease, age greater than or equal to 75 years, prior hemorrhage, or hypertension. Each of the following categories is given points if present in the patient:
Anemia = 3 points
Severe renal disease (e.g., glomerular filtration rate < 30 ml/min or dialysis-dependent) = 3 points
Age greater than or equal to 75 years = 2 points
Prior hemorrhage = 1 point
Diagnosed hypertension = 1 point
Body System
Measured Factor High Impact
  • Hemorrhage rates are 0.76% in the low risk group (0-3 points), 2.6% in intermediate risk (4 points), and 5.8% in high risk (5-10 points)
  • It is reasonable to start warfarin if low risk
  • Consider alternatives to warfarin if intermediate risk
  • Strongly considering alternatives to warfarin if high risk.

Result Interpretation

Ranges Ranges
  • Critical High: High risk: score is from 5-10 points corresponding to hemorrhagic rate of 5.8 | Considering alternatives to warfarin is strongly advised, because warfarin likely causes hemorrhage.
  • Normal: 0
  • Normal Adult Male: 0
  • Normal Adult Female: 0
  • Normal Geriatric Male: 0
  • Normal Geriatric Female: 0
Result High Conditions
  • intracranial hemorrhage
  • extracranial hemorrhage
Test Limitations
The ATRIA bleeding risk score when compared to other bleeding risk tests was shown to overestimate the risk of bleeding in some patients. Moreover, when the ATRIA bleeding risk score was compared to the ORBIT risk score, the ORBIT score was determined to be superior to the ATRIA score.
References: 2


Study Validation 1
A comparison of several bleeding risk scores including the ATRIA score was done using the data from the RE-LY trial. The ATRIA score was able to establish a significant trend (P < 0.001) showing the difference in major bleeding when patients used dabigatran compared to warfarin. The ATRIA score did tend to overestimate the bleeding risk compared to the other scores. However, the study concludes that the ORBIT, ATRIA, and HEMORR2 HAGES risk scores are capable of determining a significant risk of bleeding based on their individual factors.
References: 3
Study Validation 2
In a study that compared ATRIA, HAS-BLED, and ORBIT scores, all three scores were able to predict bleeding events. In this study, HAS-BLED showed the best performance in establishing a significant connection between risk score and bleeding outcomes. When a time in therapeutic range value related to warfarin therapy was added to the ATRIA and ORBIT scores, they were able to show a much higher correlation between risk score and bleeding events.
References: 4
Study Validation 3
In a comparison of several bleeding risk scores, all were found to show a correlation between risk score and bleeding events. The CHA2DS2-VAsc score was shown to have the most significant performance in predicting bleeding events. However, there was no statisical significance in the difference between the scores, and all of the scores were determined to provide similar insight in predicting bleeding events.
References: 5


Daniel Singer, MD, is a professor of medicine at Harvard Medical School and professor in the Department of Epidemiology at Harvard School of Public Health. He serves as an associate Chief for Research, MGH Division of General Internal Medicine and a Fellowship Site Director at Harvard Medical School. He is also a professor in the Department of Epidemiology of the Massachusetts General Hospital. Dr. Singer is best known for his research on prevention of stroke in atrial fibrillation,


  1. Fang MC, Go AS, Chang Y, Borowsky LH, Pomernacki NK, Udaltsova N, Singer DE. A New Risk Scheme to Predict Warfarin-Associated Hemorrhage: the AnTicoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study. J Am Coll Cardiol. 2011 Jul 19; 58(4): 395-401.
  2. Proietti M, Hijazi Z, Andersson U, Connelly SJ, Eikelboom JW, Ezekowitz MD, Lane DA, et al. Comparison of bleeding risk scores in patients with atrial fibrillation: insights from the RE-LY trial. J Intern Med. 2018 Mar; 283(3): 282-292.
  3. Proietti M, Hijazi Z, Andersson U, Connelly SJ, Eikelboom JW, Ezekowitz MD, Lane DA, Oldgren J, Roldan V, Yusuf S, Wallentin L. Comparison of bleeding risk scores in patients with atrial fibrillation: insights from the RE-LY trial. J Intern Med. 2018 Mar; 283(3): 282-292.
  4. Senoo K, Proietti M, Lane DA, Lip GY. Evaluation of the HAS-BLED, ATRIA, and ORBIT Bleeding Risk Scores in Patients with Atrial Fibrillation Taking Warfarin. Am J Med. 2016 Jun; 129(6): 600-7.
  5. Yao X, Gersh BJ, Sangaralingham LR, Kent DM, Shah ND, Abraham NS, Noseworthy PA. Comparison of the CHA2DS2-VASc, CHADS2, HAS-BLED, ORBIT, and ATRIA Risk Scores in Predicting Non-Vitamin K Antagonist Oral Anticoagulants-Associated Bleeding in Patients With Atrial Fibrillation. Am J Cardiol. 2017 Nov 1;120(9):1549-1556.

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