CKD is associated with a higher risk of stroke/thromboembolism across stroke risk strata in AF patients. High-risk CKD patients (CHA₂DS₂-VASc ≥2) with AF benefit from warfarin treatment for stroke prevention.

Study queStionWhat are the risks of all cause mortality, thromboembolism, major bleeding, and recurrent gastrointestinal bleeding associated with restarting antithrombotic treatment after gastrointestinal bleeding in patients with atrial fibrillation? MethodSThis Danish cohort study (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) included all patients with atrial fibrillation discharged from hospital after gastrointestinal bleeding while receiving antithrombotic treatment. Restarted treatment regimens were single or combined antithrombotic drugs with oral anticoagulation and antiplatelets. Follow-up started 90 days after discharge to avoid confounding from use of previously prescribed drugs on discharge. Risks of all cause mortality, thromboembolism, major bleeding, and recurrent gastrointestinal bleeding were estimated with competing risks models and time dependent multiple Cox regression models.Study anSwer and liMitationS 4602 patients (mean age 78 years) were included. Within two years, 39.9% (95% confidence interval 38.4% to 41.3%, n=1745) of the patients had died, 12.0% (11.0% to 13.0%, n=526) had experienced thromboembolism, 17.7% (16.5% to 18.8%, n=788) major bleeding, and 12.1% (11.1% to 13.1%, n=546) recurrent gastrointestinal bleeding. 27.1% (n=924) of patients did not resume antithrombotic treatment. Compared with non-resumption of treatment, a reduced risk of all cause mortality was found in association with restart of oral anticoagulation (hazard ratio 0.39, 95% confidence interval 0.34 to 0.46), an antiplatelet agent (0.76, 0.68 to 0.86), and oral anticoagulation plus an antiplatelet agent (0.41, 0.32 to 0.52), and a reduced risk of thromboembolism was found in association with restart of oral anticoagulation (0.41, 0.31 to 0.54), an antiplatelet agent (0.76, 0.61 to 0.95), and oral anticoagulation plus an antiplatelet agent (0.54, 0.36 to 0.82). Restarting oral anticoagulation alone was the only regimen with an increased risk of major bleeding (1.37, 1.06 to 1.77) compared with nonresumption of treatment; however, the difference in risk of recurrent gastrointestinal bleeding was not significant between patients who restarted an antithrombotic treatment regimen and those who did not resume treatment. what thiS Study addSAmong patients with atrial fibrillation who experience gastrointestinal bleeding while receiving antithrombotic treatment; subsequent restart of oral anticoagulation alone was associated with better outcomes for all cause mortality and thromboembolism compared with patients who did not resume treatment. This was despite an increased longitudinal associated risk of bleeding.

Background Comparative data of non‐vitamin K antagonist oral anticoagulants (NOAC) are lacking in patients with atrial fibrillation (AF). Objective We compared effectiveness and safety of standard and reduced dose NOAC in AF patients. Methods Using Danish nationwide registries, we included all oral anticoagulant‐naïve AF patients who initiated NOAC treatment (2012–2016). Outcome‐specific and mortality‐specific multiple Cox regressions were combined to compute average treatment effects as 1‐year standardized differences in stroke and bleeding risks (g‐formula). Results Amongst 31 522 AF patients, the distribution of NOAC/dose was as follows: dabigatran standard dose (22.4%), dabigatran‐reduced dose (14.0%), rivaroxaban standard dose (21.8%), rivaroxaban reduced dose (6.7%), apixaban standard dose (22.9%), and apixaban reduced dose (12.2%). The 1‐year standardized absolute risks of stroke/thromboembolism were 1.73–1.98% and 2.51–2.78% with standard and reduced NOAC dose, respectively, without statistically significant differences between NOACs for given dose level. Comparing standard doses, the 1‐year standardized absolute risk (95% CI) for major bleeding was for rivaroxaban 2.78% (2.42–3.17%); corresponding absolute risk differences (95% CI) were for dabigatran −0.93% (−1.45% to −0.38%) and apixaban, −0.54% (−0.99% to −0.05%). The results for major bleeding were similar for reduced NOAC dose. The 1‐year standardized absolute risk (95% CI) for intracranial bleeding was for standard dose dabigatran 0.19% (0.22–0.50%); corresponding absolute risk differences (95% CI) were for rivaroxaban 0.23% (0.06–0.41%) and apixaban, 0.18% (0.01–0.34%). Conclusions Standard and reduced dose NOACs, respectively, showed no significant risk difference for associated stroke/thromboembolism. Rivaroxaban was associated with higher bleeding risk compared with dabigatran and apixaban and dabigatran was associated with lower intracranial bleeding risk compared with rivaroxaban and apixaban.

Among anticoagulant-naïve AF patients, treatment with NOACs was not associated with significantly lower risk of stroke/TE compared with VKA, but intracranial bleeding risk was significantly lower with dabigatran and apixaban.

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