HAS-BLED Bleeding Risk Score

HAS-BLED is a validated clinical score estimating the 1-year risk of major bleeding in patients with atrial fibrillation who are being considered for, or are taking, anticoagulation. It was developed by Pisters et al. and published in Chest (2010).

Each letter represents a risk factor: Hypertension, Abnormal renal/liver function, Stroke, Bleeding history, Labile INR, Elderly (>65), and Drugs/alcohol. Most score 1 point each; abnormal renal/liver function and drugs/alcohol can each contribute up to 2 points. Maximum score: 9.

HAS-BLED is designed to be used alongside a stroke-risk score such as CHA₂DS₂-VASc — not as a standalone reason to avoid anticoagulation.

Source: Pisters R et al. Chest 2010;138(5):1093–1100 (original cohort; rates are per 100 patient-years). Scores of 5 and above had small numbers; 6 to 9 had insufficient data. "High risk" for 3 or more follows NPS MedicineWise.

The 2018 Australian Clinical Guidelines for AF (NHFA/CSANZ) state that bleeding risk scores should not be used on their own to avoid anticoagulation, and that a higher score should prompt attention to modifiable risk factors.

Decisions about anticoagulation are made between a patient and their prescriber, taking into account stroke risk as well as bleeding risk. This page is general information only and is not medical advice.

Source: NHFA/CSANZ AF Guideline Working Group. Heart Lung Circ 2018;27:1209–1266.

HAS-BLED was validated primarily in patients taking warfarin. Its performance in patients taking a DOAC is a separate question not covered by this page. The "Labile INR" component refers to INR control, which applies to people monitored with an INR.

The score does not capture every bleeding risk factor (e.g. frailty, falls risk, specific drug interactions) and should be interpreted alongside the whole clinical picture, not in isolation.

This tool is a decision aid, not a decision maker. Any change to anticoagulation should be made in discussion with the prescribing clinician.