Oral anticoagulants in patients with atrial fibrillation at low stroke risk: a multicentre observational study.

There is currently no consensus on whether atrial fibrillation (AF) patients at low risk for stroke (one non-sex-related CHA2DS2-VASc point) should be treated with an oral anticoagulant. We conducted a multi-country cohort study in Sweden, Denmark, Norway, and Scotland. In total, 59 076 patients diagnosed with AF at low stroke risk were included. We assessed the rates of stroke or major bleeding during treatment with a non-vitamin K antagonist oral anticoagulant (NOAC), a vitamin K antagonist (VKA), or no treatment, using inverse probability of treatment weighted (IPTW) Cox regression. In untreated patients, the rate for ischaemic stroke was 0.70 per 100 person-years and the rate for a bleed was also 0.70 per 100 person-years. Comparing NOAC with no treatment, the stroke rate was lower [hazard ratio (HR) 0.72; 95% confidence interval (CI) 0.56-0.94], and the rate for intracranial haemorrhage (ICH) was not increased (HR 0.84; 95% CI 0.54-1.30). Comparing VKA with no treatment, the rate for stroke tended to be lower (HR 0.81; 95% CI 0.59-1.09), and the rate for ICH tended to be higher during VKA treatment (HR 1.37; 95% CI 0.88-2.14). Comparing NOAC with VKA treatment, the rate for stroke was similar (HR 0.92; 95% CI 0.70-1.22), but the rate for ICH was lower during NOAC treatment (HR 0.63; 95% CI 0.42-0.94). These observational data suggest that NOAC treatment may be associated with a positive net clinical benefit compared with no treatment or VKA treatment in patients at low stroke risk, a question that can be tested through a randomized controlled trial.

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© The Author(s) 2022. Published by Oxford University Press on behalf of European Society of Cardiology.

Déclaration de conflit d'intérêts

Conflict of interest: J.J.K. is currently employed by Daiichi-Sankyo, but not during the conduct of this study, and reports personal fees from Boehringer Ingelheim, outside the submitted work; A.P. reports grants from Alcon, grants from Almirall, grants from Astellas, grants from Astra-Zeneca, grants from Boehringer Ingelheim, grants from Novo Nordisk, grants from Servier, grants from LEO Pharma, outside the submitted work; Ø.K. reports participation in imposed Post-Authorization Safety Studies on an antidiabetic and an anti-psoriasis drug. The studies are funded by Leo Pharma and Novo Nordisk, with funds paid to the institution where he is employed (no personal fees) and with no relation to the work reported in this paper; L.J.K. was supported by the Research Council of Norway as part of the International Pregnancy Drug Safety Studies (InPreSS, Project No. 273366) during the conduct of the study. All other authors have nothing to declare.