HAS-BLED Bleeding Risk Calculator

About the HAS-BLED Bleeding Risk Calculator

Estimate the risk of a major bleed for an adult with atrial fibrillation who takes, or may start, an anticoagulant, with two published scores:

• HAS-BLED — Hypertension, Abnormal kidney or liver function, Stroke, Bleeding, Labile INR, Elderly, Drugs or alcohol, 1 point each (0 to 9) — with the major bleeds per 100 patient-years the Euro Heart Survey found at each score; 3 or more is high risk;
• ORBIT — Older age, Reduced haemoglobin, Bleeding history, Insufficient kidney function, Treatment with an antiplatelet (0 to 7 points) — the score NICE recommends because it predicts the absolute risk more accurately, with the rates of the ORBIT-AF registry.

Each result lists the factors present that can be changed — uncontrolled blood pressure, poor INR control, antiplatelets or NSAIDs, alcohol, anaemia — with what NICE advises for each, and the score without them. A high score is a reason to work on those and review more often, not on its own a reason to withhold anticoagulation; the stroke side of the decision is the CHA2DS2-VASc score. Written for clinicians; nothing leaves your browser.

Without a pass, the free preview shows the HAS-BLED or ORBIT score in full, with its risk group, its rate of major bleeding, the factors you can change and the first rows of each table; a Pro pass unlocks the score without the modifiable factors, the whole tables and Copy result.

Common uses

• Documenting bleeding risk when anticoagulation for atrial fibrillation is started or reviewed.
• Finding the modifiable factors — blood pressure, INR control, antiplatelets, NSAIDs, alcohol, anaemia — before a review.
• Comparing HAS-BLED with ORBIT, the score NICE recommends, for the same patient.
• Teaching students how the two bleeding scores are built and what their figures mean.

HAS-BLED: the items

• Hypertension: uncontrolled, systolic above 160 mmHg — 1
• Abnormal kidney function (chronic dialysis, kidney transplant, or serum creatinine 200 µmol/L — 2.26 mg/dL — or more) and abnormal liver function (chronic liver disease such as cirrhosis, or bilirubin over twice the upper limit of normal with AST, ALT or ALP over 3 times the upper limit) — 1 each
• Stroke: previous stroke — 1
• Bleeding: previous bleeding or a predisposition to bleeding, such as a bleeding disorder or anaemia — 1
• Labile INR: unstable or high INRs, or under 60% of the time in the therapeutic range — 1 (this item assumes a vitamin K antagonist such as warfarin)
• Elderly: older than 65 — 1
• Drugs (an antiplatelet or NSAID taken with the anticoagulant) and alcohol abuse or excess — 1 each

HAS-BLED: bleeding rate by score

In the Euro Heart Survey (3,978 people with atrial fibrillation, followed for a year), the rate of major bleeding per 100 patient-years was 1.13 at a score of 0, 1.02 at 1, 1.88 at 2, 3.74 at 3, 8.70 at 4 and 12.5 at 5. Major bleeding meant intracranial bleeding, or bleeding that led to admission to hospital, a large fall in haemoglobin or a transfusion. The guideline that reprints these figures lists them up to a score of 5 and defines a score of 3 or more as high risk; it names no lower groups, so below 3 the calculator gives the rate at each score.

ORBIT: the items and rates

• Older: 75 or over — 1
• Reduced haemoglobin (below 13 g/dL in men, 12 g/dL in women), haematocrit (below 40% in men, 36% in women) or a history of anaemia — 2
• Bleeding history: any gastrointestinal or intracranial bleeding, or haemorrhagic stroke — 2
• Insufficient kidney function: eGFR below 60 mL/min/1.73 m² — 1
• Treatment with an antiplatelet — 1

In ORBIT-AF (7,411 people taking an oral anticoagulant), major bleeds per 100 patient-years were 1.7, 2.3, 2.9, 4.7, 6.8, 9.0, 12.3 and 14.9 at scores of 0 to 7; 2.4 in the low group (0 to 2), 4.7 in the medium group (3) and 8.1 in the high group (4 to 7). Major bleeding followed the International Society on Thrombosis and Haemostasis definition.

Which score: NICE and ORBIT

NICE asks clinicians to assess bleeding risk when anticoagulation is considered and when people already taking it are reviewed, using ORBIT, because the evidence showed it predicts the absolute risk of major bleeding more accurately than HAS-BLED or ATRIA, for vitamin K antagonists and direct-acting oral anticoagulants alike. Other tools may be used until ORBIT is part of local pathways and software. NICE is explicit that a bleeding risk tool should not set a cut-off for who gets anticoagulation: it informs the discussion of risk, of what can be modified and of how closely to follow the person up.

Not every guideline agrees on the tool. The Brazilian atrial fibrillation guideline keeps HAS-BLED, citing a meta-analysis in which ORBIT did not predict major bleeding better, and uses it to find the modifiable factors in people at high risk; it too says a score of 3 or more is not a contraindication to anticoagulation.

The factors you can change

NICE recommends monitoring and support to modify these bleeding risk factors:

• uncontrolled hypertension;
• poor control of the INR in people taking a vitamin K antagonist;
• concurrent medicines, including antiplatelets, selective serotonin reuptake inhibitors (SSRIs) and NSAIDs;
• harmful alcohol consumption;
• reversible causes of anaemia.

Age, a previous bleed or stroke and established kidney or liver disease cannot be undone; kidney function still needs regular checks in people with kidney impairment who take a direct-acting oral anticoagulant. The calculator marks each factor as modifiable, partly modifiable or fixed.

The stroke side: CHA2DS2-VASc

Bleeding risk is weighed against the risk of stroke. NICE uses the CHA2DS2-VASc score for stroke risk in atrial fibrillation and atrial flutter: in the evidence it reviewed, a score of 2 or more was the threshold that indicated a need for anticoagulation, and men with a score of 1 were at intermediate risk. Hypertension, a previous stroke and age appear in both scores, so many people at high bleeding risk are also at high stroke risk.

Sources

• Pisters R et al. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey
• Japanese Circulation Society and Japanese Heart Rhythm Society, guideline on pharmacotherapy of cardiac arrhythmias — HAS-BLED table and bleeding rates by score
• O’Brien EC et al. The ORBIT bleeding score: a simple bedside score to assess bleeding risk in atrial fibrillation — tables 2 and 3
• NICE guideline NG196, Atrial fibrillation: diagnosis and management — recommendations 1.2.1 to 1.2.4 (risk scores and modifiable factors) and 1.6.17 (yearly review, kidney function on a direct-acting oral anticoagulant)
• Brazilian Atrial Fibrillation Guidelines — bleeding risk assessment, HAS-BLED and ORBIT
• Practical recommendations for anticoagulation in patients with atrial fibrillation — modifiable bleeding risk factors and the use of bleeding scores

Limitations

• For adults with atrial fibrillation. HAS-BLED was derived in the Euro Heart Survey, whose patients took a vitamin K antagonist, antiplatelets or neither; ORBIT in a registry of people taking an oral anticoagulant, most of them warfarin. Rates with today’s direct-acting oral anticoagulants may differ.
• The rates describe groups in the source studies, not one person; a score does not decide treatment, and bleeding risk changes over time, so it is reassessed at reviews.
• The labile INR item applies only to vitamin K antagonists such as warfarin.
• Other conditions, such as venous thromboembolism, use other bleeding scores.

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