HAS-BLED Score Calculator

A score of 3 or more is the conventional cutoff for "high risk" of major bleeding on anticoagulation, corresponding to roughly a 3.7% or higher estimated annual bleeding rate in the original derivation cohort. It is a prompt for closer monitoring and correcting modifiable risk factors -- like uncontrolled blood pressure or concurrent NSAID use -- rather than an automatic reason to withhold anticoagulation that a patient's stroke risk otherwise justifies.

Several of the nine are not fixed patient characteristics: uncontrolled hypertension can be treated, a labile INR can potentially be improved with more frequent monitoring or a switch to a non-vitamin-K anticoagulant, and concurrent antiplatelet or NSAID use can sometimes be stopped or substituted. Age, prior stroke, and prior bleeding history, by contrast, cannot be changed, which is part of why HAS-BLED is meant to guide risk-factor correction rather than function as a simple stop/go gate.

Not perfectly -- the original Pisters et al. cohort actually reported a very slightly lower annual bleeding rate at a score of 1 (about 1.0%) than at a score of 0 (about 1.1%), before rates climb clearly at higher scores. This kind of small non-monotonic step at low scores is a known feature of the derivation data, likely reflecting smaller patient counts at that exact score, and is a reminder that any one point on a risk curve carries wider uncertainty than the headline percentage suggests.

No -- the two scores answer different questions and are meant to be read together. CHA2DS2-VASc estimates the stroke risk anticoagulation is trying to prevent, while HAS-BLED estimates the bleeding risk anticoagulation can cause; a clinician weighs both rather than picking one, since a patient can simultaneously have a high stroke risk that justifies anticoagulation and a high bleeding risk that calls for extra monitoring while on it.