0
Correspondence |

Response FREE TO VIEW

Ron Pisters, MD; Deirdre A. Lane, PhD; Robby Nieuwlaat, PhD; Harry J. G. M. Crijns, MD; Gregory Y. H. Lip, MD
Author and Funding Information

From the University of Birmingham Centre for Cardiovascular Sciences (Drs Pisters, Lane, and Lip), City Hospital: and the Department of Cardiology, Maastricht University Medical Centre (Drs Nieuwlaat and Crijns).

Correspondence to: Gregory Y. H. Lip, MD, University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham B18 7QH, England; e-mail: g.y.h.lip@bham.ac.uk


Financial/nonfinancial disclosures: The authors have reported to CHEST the following conflicts of interest: Dr Pisters has consulting fees from Bayer and Boehringer Ingelheim and lecture fees from Boehringer Ingelheim. Dr Lane is the recipient of an investigator-initiated educational grant from Bayer Healthcare and has received sponsorship to attend the European Society of Cardiology Congress 2009 from AstraZeneca. Dr Crijn has received consulting fees from Boehringer Ingelheim, Sanofi-Aventis, and AstraZeneca; grant support from St. Jude Medical, Boston Scientific, Boehringer Ingelheim, Sanofi-Aventis, Medapharma, and Merck; and honoraria from Medtronic, Sanofi-Aventis, Medapharma, Merck, Boehringer Ingelheim, and Biosense Webster. Dr Lip has served as a consultant for Bayer, Astellas, Merck, AstraZeneca, Sanofi-Aventis, Aryx, Portola, Biotronic, and Boehringher Ingelheim, and has been on the speakers bureau for Bayer, Boehringher Ingelheim, and Sanofi-Aventis. Dr Nieuwlaat has reported that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (http://www.chestpubs.org/site/misc/reprints.xhtml).


© 2011 American College of Chest Physicians


Chest. 2011;139(5):1248. doi:10.1378/chest.11-0184
Text Size: A A A
Published online

To the Editor:

Dr Corbanese raises the question as to whether the C statistic suffices as a comprehensible measure of predictive accuracy of our novel bleeding risk model, HAS-BLED (hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly [>65 years], drugs/alcohol concomitantly). We acknowledge that the C statistic has its shortcomings, although it is used widely in many validation studies of risk-scoring systems. In addition, the moderate size of the Euro Heart Survey study population1 was reason not to apply the complex statistics proposed by Dr Corbanese in our analysis.

However, in a recent second validation of HAS-BLED, Lip et al2 tested the different statistical methods on the available bleeding risk models in a much larger clinical trial cohort (>7,000 patients). In this study, univariate Cox regression was used to estimate the hazard ratios and 95% CIs for individual risk factors, with major bleeding as the dependent variable. All potential risk factors investigated in the univariate analyses were included in the multivariate Cox regression analyses; only those variables with P values that remained significant at the 5% level in the presence of other selected variables were retained in the final model. Then, C statistics were estimated to quantify the predictive accuracy of the risk schemes, with 95% CIs obtained by bootstrapping analyses.

The Hosmer-Lemeshow test for calibration was also performed by Lip et al2 in conjunction with all C statistics, and none of the P values was ≤ .05 for any of the risk scores (ie, lack of goodness of fit was not indicated). For HAS-BLED in particular, the P values were .24 for all patients and .13 for the warfarin patient cohort. Furthermore, using multivariate Cox regression models, Lip et al2 tested whether the HAS-BLED score added significantly to models already incorporating the four older scores, one at a time. In all four instances, HAS-BLED was associated with predictive improvement when inserted into models already incorporating the older scores. In contrast, none of the other four older scores added significantly when inserted one at a time into a model already including HAS-BLED. Thus, we hope we have clarified the interpretation of the predictive accuracy of the HAS-BLED model, as well as its comparison with the other bleeding risk models, in the second validation study, which had a much larger sample size and used other statistical methods beyond the C statistic,2 as suggested by Dr Corbanese.

Pisters R, Lane DA, Nieuwlaat R, de Vos CB, Crijns HJGM, Lip GYH. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey. Chest. 2010;1385:1093-1100. [CrossRef] [PubMed]
 
Lip GY, Frison L, Halperin JL, Lane DA. Comparative validation of a novel risk score for predicting bleeding risk in anticoagulated patients with atrial fibrillation: the HAS-BLED (hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile INR, elderly, drugs/alcohol concomitantly) score. J Am Coll Cardiol. 2011;572:173-180. [CrossRef] [PubMed]
 

Figures

Tables

References

Pisters R, Lane DA, Nieuwlaat R, de Vos CB, Crijns HJGM, Lip GYH. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey. Chest. 2010;1385:1093-1100. [CrossRef] [PubMed]
 
Lip GY, Frison L, Halperin JL, Lane DA. Comparative validation of a novel risk score for predicting bleeding risk in anticoagulated patients with atrial fibrillation: the HAS-BLED (hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile INR, elderly, drugs/alcohol concomitantly) score. J Am Coll Cardiol. 2011;572:173-180. [CrossRef] [PubMed]
 
NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543