ORBIT bleeding score: how the five-item points total works
The ORBIT bleeding score adds points for five items: age 75 or older (1), anemia (2), bleeding history (2), insufficient kidney function (1) and antiplatelet use (1). The total runs from 0 to 7. A score of 0 to 2 is low, 3 is intermediate and 4 or more is high.
Not a medical device. Not a diagnosis or dosing recommendation.
What is the ORBIT bleeding score?
ORBIT is a bleeding-risk score for people with atrial fibrillation (AF). It was described by O'Brien and colleagues in the European Heart Journal in 2015. It's named after the ORBIT-AF registry, the data it was built from.
Magent's calculator takes age plus four true/false items and returns the total, the maximum of 7, and a risk group: low, intermediate or high.
This page explains how the points add up. It doesn't say what a score means for a particular person.
The ORBIT formula
Age 75 or older 1 point
Anemia 2 points
Bleeding history 2 points
Insufficient kidney function 1 point
Antiplatelet use 1 point
-------------------------------------------
Total 0 to 7
0 to 2 → low · 3 → intermediate · 4 or more → highExact expression the calculator uses:
ORBIT = age_ge_75 (1) + anemia (2) + bleeding_history (2) + insufficient_kidney (1) + antiplatelet (1); max 7; 0-2 low, 3 intermediate, >=4 highInputs
| Input | What you enter | Points |
|---|---|---|
age | Age in whole years, 18 to 120 | 1 if 75 or older |
anemia | true or false, as you assign it | 2 |
bleeding_history | true or false, as you assign it | 2 |
insufficient_kidney | true or false, as you assign it (the paper used eGFR below 60) | 1 |
antiplatelet | true or false, as you assign it | 1 |
How the calculation works
- Age: 75 or older adds 1 point. 74 adds nothing.
- Flags: each true item adds its points. Anemia and bleeding history count 2 each; kidney function and antiplatelet use count 1 each.
- Add the points for a total from 0 to 7.
- Risk group: 0 to 2 is
low, 3 isintermediate, 4 or more ishigh.
The calculator doesn't take a hemoglobin value or work out eGFR. You decide whether the anemia and kidney items are true.
Units
Age is in whole years. The other four inputs are true or false and have no units. An age outside 18 to 120, a non-whole age or a flag that isn't true or false is rejected with an error.
Worked examples
These use Magent's own expected values for the calculator.
Example 1: age 70, no items
- Age under 75 → 0. All flags false → 0.
- Total 0 →
low.
Example 2: the age edge
- Age 75, no other items → 1,
low. - Age 74, no other items → 0,
low.
Example 3: one item at a time, age 70
- Anemia alone → 2,
low. - Bleeding history alone → 2,
low. - Insufficient kidney function alone → 1,
low. - Antiplatelet use alone → 1,
low.
Example 4: age 75 with anemia
- Age 75 → 1. Anemia → 2.
- Total 3 →
intermediate.
Example 5: age 75 with anemia and insufficient kidney function
- 1 + 2 + 1.
- Total 4 →
high.
Example 6: every item
- 1 + 2 + 2 + 1 + 1.
- Total 7, the maximum →
high.
History of the ORBIT score
The calculator cites O'Brien EC, Simon DN, Thomas LE and colleagues, The ORBIT bleeding score: a simple bedside score to assess bleeding risk in atrial fibrillation, European Heart Journal, 2015. According to the abstract, the authors used the ORBIT-AF registry of people with AF taking oral anticoagulation at US sites. They kept the five most predictive factors and weighted each by how strongly it was linked to major bleeding. The anemia item covered reduced hemoglobin, reduced hematocrit or a history of anemia. They compared the score with HAS-BLED and ATRIA, and also tested it in the ROCKET-AF trial population.
When it's used
The 2015 paper applied ORBIT to adults with atrial fibrillation who were taking oral anticoagulation.
Where it's used
ORBIT needs age and four yes/no items, nothing more. No lab value is entered directly, though the anemia and kidney items rest on lab results.
Who uses it
The person using the calculator assigns the four true/false items and enters age. The calculator adds the points and assigns the risk group.
Limits of the calculation
- The calculator doesn't check whether anemia or insufficient kidney function is present. It takes your true/false answer.
- It returns a points total and a group, not a bleeding rate.
- It isn't HAS-BLED, and the scores aren't interchangeable.
- A bleeding score doesn't weigh stroke risk. That's a separate score.
- This page doesn't say what to do with a score.
Clinical decisions belong to a qualified clinician who knows the patient.
How it differs from related calculators
- HAS-BLED is another AF bleeding score with different items.
- ATRIA uses anemia, severe kidney disease, age, prior bleeding and hypertension.
- HEMORR2HAGES is another bleeding score with its own items.
- CHA2DS2-VASc estimates stroke risk, not bleeding risk.
Glossary
- Atrial fibrillation (AF): an irregular heart rhythm.
- Oral anticoagulation: blood-thinning medicine taken by mouth.
- Antiplatelet: a medicine that makes platelets less sticky, such as aspirin.
- eGFR: estimated glomerular filtration rate, a measure of kidney function.
Common mistakes
- Scoring age 74 as a point. The age point starts at 75.
- Giving anemia or bleeding history 1 point. Each counts 2.
- Swapping ORBIT and HAS-BLED. They use different items and groups.
- Entering a hemoglobin value. For anemia the calculator takes true or false, not a number.
Source
O'Brien EC, Simon DN, Thomas LE, et al. The ORBIT bleeding score: a simple bedside score to assess bleeding risk in atrial fibrillation. Eur Heart J. 2015;36(46):3258-3264. DOI: 10.1093/eurheartj/ehv476. PMID: 26424865
Frequently asked questions
How is the ORBIT bleeding score calculated?
Add 1 for age 75 or older, 2 for anemia, 2 for bleeding history, 1 for insufficient kidney function and 1 for antiplatelet use.
What is a high ORBIT score?
4 or more is high. 3 is intermediate and 0 to 2 is low.
How is ORBIT different from HAS-BLED?
They're separate AF bleeding scores with different items, points and groups.
Does the calculator need a hemoglobin value?
No. You mark anemia true or false.
What is the highest ORBIT score?
7, when every item is present.