Recalibration of the HAS-BLED score: should haemorrhagic stroke account for 1 or 2 points?

Following a haemorrhagic stroke, it is uncertain whether this event scores 1 point (either for Stroke or Bleeding) or 2 points (1 point each for Stroke and Bleeding) on the HAS-BLED score. We investigated the value of a recalibration of the HAS-BLED score to account for 2 points from a haemorrhagic stroke.

We analysed data from the Danish nationwide cohort of incident atrial fibrillation (AF) patients from January 1999 to December 2013. The primary outcome in this observational study was major bleeding. The original- and the recalibrated HAS-BLED scores were assessed and event rates of major bleeding were calculated. We compared the predictive accuracy of major bleeding by C-statistics, the Net Reclassification Index (NRI) and Integrated Discrimination Improvement (IDI).

In a total of 210,299 AF patients, we observed an event rate for major bleeding of 4.3 per 100 person-years. The C-statistics for the two scores were modest: 0.613 (95%CI, 0.607-0.619) for the original and 0.616 (95%CI, 0.610-0.622) for the recalibrated. The NRI was 10.0% (95%CI 7.6%-12.4%). When assessing the NRI in less than 6 months follow-up, we observed a markedly higher NRI of 34.2%. The relative IDI was 23.6% (95%CI, 15.7%-31.5%) reflecting that the recalibrated HAS-BLED score more accurately predicted bleeding events.

Recalibration of the "S" component in the HAS-BLED score, counting 2 points for a haemorrhagic stroke, resulted in an increase in the C-statistics, NRI and IDI. This approach could potentially aid physicians in a more accurate bleeding risk assessment in AF patients.