What does ORBIT stand for?

ORBIT stands for Outcomes Registry for Better Informed Treatment of Atrial Fibrillation. The bleeding risk model was derived from that registry of over 7,000 AF patients on anticoagulation.

What counts as renal impairment for ORBIT?

The original ORBIT score defines renal impairment as an estimated GFR below 60 mL/min/1.73 m², or a history of dialysis or renal transplant.

What counts as prior bleeding?

Prior major bleeding or clinically relevant non-major bleeding (CRNMB) within the study period. This includes gastrointestinal bleeds, intracranial hemorrhage, and bleeds requiring medical attention or dose adjustment.

What is the annual bleeding rate for each risk tier?

In the ORBIT-AF registry: Low (0–2 points) ~2.4% per year; Medium (3 points) ~4.7% per year; High (4–7 points) ~8.1% per year. These rates apply to patients on therapeutic anticoagulation.

How does ORBIT compare to HAS-BLED?

Both scores predict major bleeding in AF patients on anticoagulation, but use different variables. ORBIT avoids labile INR (hard to assess prospectively) and uses a simpler 5-factor model. Studies show comparable discriminative performance (c-statistic ~0.62–0.68 for both).

Should a high ORBIT score mean stopping anticoagulation?

Not automatically. A high bleeding risk must be weighed against the thromboembolic risk (CHA2DS2-VASc score). In most AF patients, the benefit of stroke prevention outweighs bleeding risk even at high ORBIT scores. Clinical judgment is essential.

ORBIT Bleeding Score

Name: ORBIT Bleeding Score
Availability: InStock
Author: Nham Vu

Score 5 clinical factors to estimate major bleeding risk in patients on anticoagulation therapy.

Patient Factors

Check each factor that applies to the patient.

O Older Age (≥75 years)

+1 point

R Renal Impairment (GFR <60)

eGFR <60 mL/min/1.73 m², dialysis, or transplant — +1 point

B Prior Bleeding History

Major or clinically relevant non-major bleeding — +2 points

I Iron Deficiency / Anaemia

Hgb <13 g/dL (men) or <12 g/dL (women), or Hct <40% (men) / <36% (women) — +2 points

T Antiplatelet Drug Use

Concurrent aspirin, clopidogrel, prasugrel, or ticagrelor — +1 point

Select patient factors and press
Calculate ORBIT Score

ORBIT Score

/ 7 points

LowMediumHigh

Estimated Annual Major Bleeding Rate

Score Breakdown

ORBIT Risk Tiers

Score	Risk Tier	Annual Major Bleed Rate
0 – 2	Low	2.4% / year
3	Medium	4.7% / year
4 – 7	High	8.1% / year

Source: O'Brien et al., Am Heart J 2011. Rates from ORBIT-AF registry patients on therapeutic anticoagulation.

Clinical use only. This calculator is a decision-support aid. It does not replace clinical judgment. Always weigh bleeding risk against thromboembolic risk (e.g., CHA²DS²-VASc) before adjusting anticoagulation.

Summary

Score 5 clinical factors to estimate major bleeding risk in patients on anticoagulation therapy.

How it works

Enter patient age — 1 point is awarded if age is 75 or older.
Indicate if the patient is female — 1 point is awarded for female sex.
Enter renal impairment status — reduced kidney function (GFR < 60) scores 1 point.
Check prior bleeding history — any prior major or CRNMB bleeding scores 2 points.
Indicate antiplatelet drug use — 1 point is awarded for concurrent antiplatelet therapy.
The total ORBIT score (0–7) maps to a risk tier with estimated annual major bleeding rate.

Use cases

Stratify major bleeding risk before starting long-term anticoagulation.
Compare bleeding risk vs thrombotic benefit when initiating warfarin or a DOAC.
Support shared decision-making discussions with patients about anticoagulation.
Guide monitoring frequency for patients already on anticoagulation therapy.
Document clinical risk assessment in AF management plans.
Identify high-risk patients who may benefit from closer follow-up.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu