Validation of HAS-BLED scheme for predicting bleeding risk

BIRMINGHAM, UNITED KINGDOM. A new scheme, HAS-BLED, was recently developed as a means of predicting bleeding risks in atrial fibrillation (AF) patients receiving antithrombotic treatment. Now a team of researchers from England, Sweden and the United States reports their evaluation of the validity of the scheme in a group of 7,329 AF patients at moderate to high risk of stroke who were anticoagulated with warfarin (3,665 patients) or ximelagatran (no longer available). They compared the HAS-BLED scheme to four other less well known schemes and found HAS-BLED to be superior.

In looking at the actual risk factors in the overall group (warfarin and ximelagatran), they found (in multivariate analysis) that the following factors were independent predictors of an increased risk of bleeding when being anticoagulated.

  • Concomitant aspirin use – increased bleeding risk by 92%
  • Kidney dysfunction – increased bleeding risk by 90%
  • Age 75 years or greater – increased bleeding risk by 71%
  • Diabetes – increased bleeding risk by 36%
  • Left ventricular dysfunction – increased bleeding risk by 31%

Applying the HAS-BLED scoring system to the whole patient group resulted in the following annual risk (%/year) of suffering a major bleed when on warfarin or ximelagatran.

HAS-BLED Score
Entire Group, %/year
Warfarin Only, %/year
0
1.2
0.9
1
2.8
3.4
2
3.6
4.1
3
6.0
5.8
4
9.5
8.9
5
7.4
9.1

The most important risk factors for bleeding events as predicted by HAS-BLED were:

  • Labile (varying) INR – increased risk by 105% (106%)
  • Use of aspirin or NSAIDs – increased risk by 85% (96%)
  • Kidney dysfunction – increased risk by 77% (NS)
  • Age above 75 years at entry increased risk by 76% (82%)

NOTE: Numbers in brackets indicate risk increases for warfarin group only.

The authors conclude that the HAS-BLED scheme may provide a useful assessment of bleeding risk in AF patients in everyday clinical practice.

Lip, GYH, et al. Comparative validation of a novel risk score for predicting bleeding risk in anticoagulated patients with atrial fibrillation. Journal of the American College of Cardiology, Vol. 57, No. 2, January 11, 2011, pp. 173-80
Hohnloser, SH. Stroke prevention versus bleeding risk at atrial fibrillation. Journal of the American College of Cardiology, Vol. 57, No. 2, January 11, 2011, pp. 181-83

Editor’s comment: Inadequate control of INR is clearly the most important factor in estimating the risk of bleeding when anticoagulated. Concomitant use of aspirin, kidney dysfunction, and age of 75 years or older are also important factors, although the authors emphasize that, “bleeding in elderly patients with AF is more related to biological age rather than chronological age.” It would also seem that it may be wise to add diabetes and left ventricular dysfunction to the factors that can increase bleeding risk. Finally, the huge importance of adequate INR control may make the use of an INR home testing kit a worthwhile investment for afibbers on warfarin.