HAS-BLED estimates the one-year risk of major bleeding in people with atrial fibrillation who are taking, or being considered for, an oral anticoagulant. It is the companion to CHA₂DS₂-VASc: that score weighs stroke risk, this one weighs bleeding risk. Its most useful job is to point at bleeding risk factors that can be corrected. The point for age is taken from the age field rather than a checkbox, so it always matches the age entered.
- What it estimates
- One-year major bleeding risk in AF
- Applies to
- Atrial fibrillation, on or considering anticoagulation
- Score range
- 0 to 9 points
- High risk
- 3 points or more
- Original derivation
- Pisters et al., Chest 2010 (Euro Heart Survey)
Formula
HAS-BLED (Pisters 2010, Euro Heart Survey)Score = Hypertension (1) + Abnormal renal function (1) + Abnormal liver function (1) + Stroke (1) + Bleeding (1) + Labile INR (1) + Elderly, age > 65 (1) + Drugs (1) + Alcohol (1)
- H
- — Uncontrolled hypertension, systolic > 160 mmHg — 1
- A
- — Abnormal renal function and/or abnormal liver function — 1 each
- S
- — Prior stroke — 1
- B
- — Prior major bleeding or predisposition to bleeding — 1
- L
- — Labile INRs, in patients on warfarin or another vitamin K antagonist — 1
- E
- — Elderly, age over 65 — 1
- D
- — Antiplatelet drugs or NSAIDs, and/or alcohol — 1 each
The A and D letters each carry two separate points, which is why nine components fit into seven letters and the maximum is 9. The bleeding rates shown are from the Pisters 2010 derivation cohort of 3,978 patients, in which 53 major bleeds occurred over a year of follow-up. Few patients scored above 5, so no rate is given for scores 6 to 9.
HAS-BLED Calculator examples
| Input | Result | Category |
|---|---|---|
| Age 58, no risk factors | 0 points | Low risk |
| Age 72, no other risk factors | 1 point | Moderate risk |
| Age 70, taking aspirin | 2 points | Moderate risk |
| Age 76, uncontrolled BP, labile INR | 3 points | High risk |
| Age 81, prior stroke, prior bleed, NSAIDs | 4 points | High risk |
| Age 68, renal and liver disease, prior bleed, labile INR, alcohol | 6 points | High risk |
What is the HAS-BLED score?
Oral anticoagulants prevent most strokes in atrial fibrillation, but they increase the risk of bleeding. HAS-BLED was published in 2010 as a simple bedside tool for estimating that bleeding risk, using factors a clinician already knows from the history, blood pressure and routine blood tests.
It was developed in 3,978 patients from the Euro Heart Survey on atrial fibrillation who had complete one-year follow-up. Major bleeding was defined as intracranial bleeding, bleeding requiring hospitalisation, a fall in haemoglobin above the study's threshold, and/or transfusion.
How is HAS-BLED calculated?
| Letter | Risk factor | Definition | Points |
|---|---|---|---|
| H | Hypertension | Uncontrolled, systolic > 160 mmHg | 1 |
| A | Abnormal renal function | Dialysis, kidney transplant, or creatinine ≥ 200 µmol/L (2.26 mg/dL) | 1 |
| A | Abnormal liver function | Chronic liver disease such as cirrhosis, or bilirubin > 2× and AST/ALT/ALP > 3× the upper limit of normal | 1 |
| S | Stroke | Prior stroke | 1 |
| B | Bleeding | Prior major bleeding or a predisposition to bleeding, such as anaemia | 1 |
| L | Labile INR | Unstable or high INRs, or time in therapeutic range < 60% — warfarin users only | 1 |
| E | Elderly | Age over 65 | 1 |
| D | Drugs | Antiplatelet agents or NSAIDs | 1 |
| D | Alcohol | 8 or more drinks a week | 1 |
| Maximum | 9 |
Hypertension in HAS-BLED means uncontrolled blood pressure, not a diagnosis of hypertension — a treated patient with a systolic pressure below 160 mmHg does not score the point. That is a common difference from CHA₂DS₂-VASc, where any history of hypertension counts.
The labile INR point only applies to people taking warfarin or another vitamin K antagonist. For someone on a direct oral anticoagulant, or not yet anticoagulated, it should be left unticked.
What does my HAS-BLED score mean?
| Score | Major bleeds per 100 patient-years | Band |
|---|---|---|
| 0 | 1.13 | Low |
| 1 | 1.02 | Moderate |
| 2 | 1.88 | Moderate |
| 3 | 3.74 | High |
| 4 | 8.70 | High |
| 5 | 12.50 | High |
| 6–9 | Insufficient data | High |
These figures come from a single derivation cohort with relatively few bleeding events, so the higher scores in particular rest on small numbers of patients. Read them as a ranking of risk rather than a precise prediction. The slight dip from 0 to 1 is in the source data.
A score of 3 or more is the conventional marker of high bleeding risk. The 2020 European Society of Cardiology atrial fibrillation guideline used that threshold to identify patients for earlier and more frequent clinical review.
Does a high HAS-BLED score mean I should stop anticoagulation?
No — not on its own. People with atrial fibrillation who have many bleeding risk factors usually have many stroke risk factors too, and for most of them anticoagulation still prevents more harm than it causes. Withholding treatment because of a bleeding score risks trading a bleed for a stroke.
The 2020 ESC guideline stated that estimated bleeding risk, in the absence of absolute contraindications, should not in itself guide decisions to use anticoagulation for stroke prevention. The 2024 ESC guideline went further: it recommends assessing and managing modifiable bleeding risk factors in everyone eligible for anticoagulation, and recommends against using bleeding risk scores to decide on starting or withdrawing it. The 2020 recommendation to consider HAS-BLED for formal bleeding risk assessment was replaced, and no specific bleeding score is recommended in its place.
Which bleeding risk factors can be changed?
- Uncontrolled blood pressure — bringing systolic pressure under control removes the H point and lowers the real risk it represents.
- Labile INRs — better INR control, or a switch to a direct oral anticoagulant where suitable, addresses the L point.
- Antiplatelet drugs and NSAIDs — review whether aspirin or another antiplatelet is still needed, and look for alternatives to anti-inflammatory painkillers.
- Alcohol — reducing intake addresses the second D point.
Age, prior stroke, a history of bleeding, and established kidney or liver disease cannot usually be reversed. They still matter: they are reasons for closer monitoring and for careful choice and dosing of the anticoagulant.
How is HAS-BLED different from CHA₂DS₂-VASc?
CHA₂DS₂-VASc estimates stroke risk and is used to decide whether anticoagulation is indicated. HAS-BLED estimates bleeding risk and is used to make anticoagulation safer once that decision is made. Several factors appear in both — age, prior stroke, and hypertension — which is why patients who score highly on one often score highly on the other.
The two are designed to be used together, but they are not weighed against each other as a simple subtraction. The stroke score drives the decision; the bleeding score drives the follow-up.
Frequently asked questions
What is a high HAS-BLED score?
A score of 3 or more is conventionally considered high bleeding risk. In the original 2010 derivation cohort, major bleeding rates rose from about 1 to 2 per 100 patient-years at scores 0 to 2 to 3.74 at a score of 3 and higher above that. A high score calls for closer review, not automatically for stopping treatment.
Should anticoagulation be withheld if HAS-BLED is 3 or more?
Not on the basis of the score alone. European guidelines state that bleeding risk scores should not be used to decide on starting or withdrawing oral anticoagulation in atrial fibrillation. Instead, a high score is a prompt to correct modifiable risk factors and to review the patient more often.
Does the labile INR point apply to DOACs?
No. The L point measures how stable warfarin control is, using unstable or high INRs or a time in therapeutic range below 60%. Direct oral anticoagulants such as apixaban or rivaroxaban are not monitored by INR, so the point does not apply and should be left unticked.
Does treated hypertension count in HAS-BLED?
Only if it is uncontrolled. HAS-BLED scores hypertension when systolic blood pressure is above 160 mmHg. A person with well-controlled hypertension on treatment does not score the point, which differs from CHA₂DS₂-VASc, where any history of hypertension counts towards the stroke score.
What is the maximum HAS-BLED score?
The maximum is 9. Although the acronym has seven letters, the A covers abnormal kidney function and abnormal liver function separately, and the D covers drugs and alcohol separately, each worth one point. Very few patients in the derivation study scored above 5, so bleeding rates for the highest scores are not available.
Can my HAS-BLED score go down?
Yes. Four of the nine points are usually modifiable: uncontrolled blood pressure, labile INRs, antiplatelet or NSAID use, and alcohol. Addressing them lowers both the score and the underlying risk it reflects. Points for age, prior stroke, prior bleeding, and kidney or liver disease generally stay.
Sources
- A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey — Pisters R et al., Chest (PubMed), 2010
- 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS) — Hindricks G et al., European Heart Journal, 2021
- 2024 ESC Guidelines for the management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS) — Van Gelder IC et al., European Heart Journal, 2024