Background Information is needed on bleeding risk factors specific for patients with atrial fibrillation (AF) treated with non-vitamin K oral anticoagulants (NOACs). We aimed to identify risk factors in a large real-world cohort and to derive a bleeding risk score for patients with AF treated with NOACs.
Methods From nationwide registries (the Norwegian Patient Registry and the Norwegian Prescription Database), we identified patients with AF with a first prescription of a NOAC between January 2013 and June 2015. Cox proportional-hazards analysis was used to identify the strongest risk factors for major or clinically relevant non-major (CRNM) bleeding. Based on these, a risk prediction score was derived. Discrimination was assessed with Harrel’s C-index. C-indexes for the modified Hypertension, Age, Stroke, Bleeding tendency/predisposition, Labile international normalised ratios, Elderly age, Drugs or alcohol excess (HAS-BLED), the Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) and the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT) scores were also calculated from the same cohort.
Results Among 21 248 NOAC-treated patients with a median follow-up time of 183 days, 1257 (5.9%) patients experienced a major or CRNM bleeding. Ten independent risk factors for bleeding were identified, which when included in a risk prediction model achieved a C-index of 0.68 (95% CI 0.66 to 0.70). A simplified score comprising three variables; age, history of bleeding and non-bleeding related hospitalisation within the last 12 months, yielded a c-index of 0.66 (95% CI 0.65 to 0.68). In the same cohort, the modified HAS-BLED, ATRIA and ORBIT scores achieved c-indexes of 0.62 (95% CI 0.60 to 0.63), 0.66 (95% CI 0.64 to 0.67) and 0.66 (95% CI 0.64 to 0.67), respectively.
Conclusions Our proposed simplified bleeding score could be a useful clinical tool for quick estimation of risk of bleeding in patients with AF treated with NOACs.
- cardiac arrhythmias
- atrial fibrillation
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Contributors WG, CJ and SH contributed in conception and design of the study. CJ, WG and SH contributed with data collection. O-CWR, RH, CJ, WG and SH contributed with data analysis and interpretation. O-CWR drafted the manuscript. CJ, RH, WG and SH critically revised the manuscript and approved the final version to be published.
Funding The study was funded by the South-Eastern Norway Regional Health Authority. Additional funding was granted by Bristol-Myers Squibb/Pfizer through the European Investigator Initiated Research Program ERISTA (Grant number CV185-619) and Helse Sør-Øst RHF.
Competing interests O-CWR reports personal fees from Boehringer Ingelheim, Novartis and Pfizer, outside the submitted work. CJ reports personal fees from Pfizer and Bayer, outside the submitted work. WG reports grants and personal fees from Bayer, grants and personal fees from Novartis, personal fees from Amgen, personal fees from Pfizer, outside the submitted work. RH reports no conflicts of interest. SH reports personal fees from Pfizer, Bayer, Boehringer Ingelheim and Bristol-Myers Squibb, outside the submitted work.
Patient consent for publication Not required.
Ethics approval Norwegian Regional Ethics Committee (Ref. No. 2015/162/REC Central).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data are available.
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