The HAS-BLED score has better prediction accuracy for major bleeding than the CHADS2 or CHA2DS2-VASc scores In anticoagulated patients with atrial fibrillation.

Roldán V, Marín F, Manzano-Fernández S et al.
J Am Coll Cardiol. 2013 Sep 13. doi: 10.1016/j.jacc.2013.08.1623. [Epub ahead of print]

Background

Different stroke risk stratification schemes exist for atrial fibrillation (AF) patients [1], such as the CHADS₂ (Congestive heart failure, Hypertension, Age >75, Diabetes mellitus, and prior Stroke or TIA [Doubled])  score [2]. The more recent CHA₂DS₂-VASc Cardiac failure or dysfunction, Hypertension, Age ≥75 [Doubled], Diabetes, Stroke [Doubled] – Vascular disease, Age 65-74 and Sex category [Female]) score focuses more on the initial identification of ‘truly low risk’ identification as the initial decision-making step [1,3,4].
Since stroke risk and bleeding risk are closely related, the CHADS₂ score closely correlates with bleeding rate [5,6]. As a result, clinicians sometimes use the CHADS₂ score or the CHA₂DS₂-VASc score as an indicator of bleeding risk. This could lead to low use of oral anticoagulation (OAC) in patients with high scores in these risk assessments [7-9].
Specific bleeding risk scores have been developed for patients with AF [10]. The HAS-BLED score (Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile INR, Elderly, Drugs/Alcohol Concomitantly) is now recommended in European and Canadian AF guidelines to estimate major bleeding risk in AF patients on anticoagulation [4, 10-12]. HAS-BLED has been shown to be a better predictor of serious bleeding both in clinical trial cohorts [13] and ‘real world’ clinical practice [14,15]. In addition, it is the only risk score that can predict intracranial bleeding in AF [13] and non-AF patients [16].
This study tested the hypothesis that the specific bleeding risk score HAS-BLED has better predictive value for major bleeding than CHADS₂ and CHA₂DS₂-VASc in AF patients on anticoagulation (with acenocoumarol and with a consistent INR between 2.0 and 3.0 over the past 6 months). 1370 patients were included and followed for a median time of 996 (IQR: 802-1254) days. 114 patients presented with a major bleeding event, of which 31 intracranial.

Main results

• Univariate analysis showed predictive value of both the CHADS₂ and CHA₂DS₂-VASc scores for bleeding events, with HR: 1.31 (95% CI:1.14-1.52; p<0.001) and HR: 1.22 (95% CI: 1.09-1.37; p=0.001),respectively. The HAS-BLED score was more predictive for major bleeds, with HR: 1.94 (95% CI: 1.66-2.28; p<0.001).
• The C-statistics for HAS-BLED (mean 0.69 + SD 0.03, P<0.001) and the multivariable model (0.71 + ).03, P<0.001) were significantly higher than those for CHADS₂ (0.59 + 0.03, P=0.002) or CHA₂DS₂-VASc (0.58 + 0.03, P=0.006) (P<0.001 for both comparisons).
• After adjustment for HAS-BLED score, both CHADS₂ and CHA₂DS₂-VASc lost their significance in predictive value in the multivariate analysis.
• Both net reclassification improvement (NRI) and integrated discrimination improvement (IDI) showed that the HAS-BLED score was more accurately associated with major bleeding episodes than with both of the other scores.

Conclusion

This study confirms the hypothesis that the HAS-BLED score is of modest but significantly better predictive value than stroke stratification scores CHADS₂ and CHA₂DS₂-VASc, for major bleeding events in anticoagulated AF patients. Consequently, the well-validated and user-friendly HAS-BLED score should be used, while use of the other scores should be avoided to assess high bleeding risk.

References

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