A bidirectional relationship exists between atrial fibrillation (AF) and chronic renal disease. Patients with AF have a higher incidence of renal dysfunction, and the latter predisposes to incident AF. The coexistence of both conditions results in a higher risk for thromboembolic-related adverse events but a paradoxical increased hemorrhagic risk. Oral anticoagulants (both vitamin K antagonists [VKAs] and non-VKA oral anticoagulants [NOACs]) have been demonstrated to be effective in mild to moderate renal dysfunction. Patients with severe renal impairment were excluded from the non-VKA oral anticoagulant trials, so limited data are available. In end-stage renal failure, the net clinical benefit of VKAs in dialysis-dependent patients remains uncertain, although some evidence suggests that such patients may do well with high-quality anticoagulation control. Risk stratification and careful follow-up of such patients are necessary to ensure a net clinical benefit from thromboprophylaxis.

Background and Purpose-Obesity is a risk factor for all-cause and cardiovascular death but, despite this, an inverse relationship between overweight or obesity and a better cardiovascular prognosis in long-term follow-up studies has been observed; this phenomenon, described as obesity paradox, has also been found evident in atrial fibrillation cohorts. Methods-We performed a systematic review on the relationship between body mass index and major adverse outcomes in atrial fibrillation patients. Moreover, we provided a meta-analysis of non-vitamin K antagonist oral anticoagulants (NOACs) trials. Results-An obesity paradox was found for cardiovascular death and all-cause death in the subgroup analyses of randomized trial cohorts; however, observational studies fail to show this relationship. From the meta-analysis of NOAC trials, a significant obesity paradox was found, with both overweight and obese patients reporting a lower risk for stroke/systemic embolic event (odds ratio