Initiation of anticoagulation in atrial fibrillation: which factors are associated with choice of anticoagulant?

• Published in: Journal of internal medicine Vol. 282; no. 2; pp. 164 - 174
• Main Authors: Gundlund, A., Staerk, L., Fosbøl, E. L., Gadsbøll, K., Sindet‐Pedersen, C., Bonde, A. N., Gislason, G. H., Olesen, J. B.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.08.2017
• Subjects: Age Factors; Aged; Aged, 80 and over; Antagonists; Anticoagulants; Anticoagulants - adverse effects; Anticoagulants - therapeutic use; apixaban; Atrial Fibrillation - complications; Cardiac arrhythmia; Cerebral infarction; comorbidity; Confidence intervals; dabigatran; Dabigatran - administration & dosage; Dabigatran - adverse effects; Dabigatran - therapeutic use; demography; Female; Fibrillation; Hemorrhage - chemically induced; Humans; Male; Myocardial infarction; Patients; Pharmacology; Population studies; Prophylaxis; Pyrazoles - administration & dosage; Pyrazoles - adverse effects; Pyrazoles - therapeutic use; Pyridones - administration & dosage; Pyridones - adverse effects; Pyridones - therapeutic use; Regression analysis; Risk Factors; rivaroxaban; Rivaroxaban - administration & dosage; Rivaroxaban - adverse effects; Rivaroxaban - therapeutic use; Stroke; Stroke - prevention & control; Vitamin K; Vitamin K - antagonists & inhibitors; warfarin; Warfarin - administration & dosage; Warfarin - adverse effects; Warfarin - therapeutic use; dabigatran; rivaroxaban; comorbidity; demography; apixaban; warfarin
• ISSN: 0954-6820; 1365-2796
• DOI: 10.1111/joim.12628

Background The use of non‐vitamin K antagonist oral anticoagulants (NOACs) for stroke prophylaxis in atrial fibrillation (AF) is increasing rapidly. We compared characteristics of AF patients initiated on NOACs versus vitamin K antagonists (VKAs). Methods Using Danish nationwide registry data, we identified AF patients initiating either a VKA or a NOAC from 22 August 2011 until 30 September 2016. We compared patient characteristics including age, gender, comorbidities, concomitant pharmacotherapy and CHA2DS2‐VASc and HAS‐BLED scores in patients initiated on a VKA, dabigatran, rivaroxaban or apixaban. Differences were examined using multivariable logistic regression models. Results The study population comprised 51 981 AF patients of whom 19 989 (38.5%) were initiated on a VKA, 13 242 (25.5%) on dabigatran, 8475 (16.3%) on rivaroxaban and 10 275 (19.8%) on apixaban. Those patients initiated on apixaban had higher mean ± SD CHA2DS2‐VASc scores than those initiated on a VKA (3.1 ± 1.6 vs. 2.9 ± 1.6). Those initiated on dabigatran had lower mean CHA2DS2‐VASc scores (2.7 ± 1.6) than all other groups. Patients with a history of a prior stroke were significantly more likely to be initiated on a NOAC compared with a VKA [odds ratio (OR) 1.35, 95% confidence interval (CI) 1.28–1.43]. By contrast, patients with a history of myocardial infarction were less likely to be initiated on a NOAC compared with a VKA (OR 0.72, 95% CI 0.67–0.77). Conclusions Atrial fibrillation patients who were initiated on apixaban had higher stroke risk scores than patients initiated on VKAs. Interestingly, opposite results were found for dabigatran.