Second, CKD increases the competing risk of death from causes unrelated to AF-associated stroke and may attenuate expected bene t of stroke prevention therapy. In a recent analysis of 7 risk strati cation scores, all had substantially poorer discrimination in CKD patients than those without CKD (c-statistics, 0.50-59 vs 0.69- 0.70, respectively), and inclusion of CKD stage did not improve calibration or discrimination.430 One study from Taiwan showed that the CHA2DS2-VASc score could adequately risk stratify for ischemic stroke among a hemodialysis population (c-index, 0.682; superior to Third, moderate to severe CKD increases the risk of major and intracranial bleeding through a number of mechanisms, and the risk may be further increased by the use of oral anticoagulation or APT. The clinical bleeding risk scores (eg, HAS-BLED, ORBIT, RIA) all include CKD measures as part of their score calculation.103 Therefore, CKD is both a marker of risk of disease and of its therapy, and there is signi cant controversy as to the net clinical bene t of oral anticoagulation in severe CKD despite encouraging observational studies.432 Fourth, there are virtually no randomized trial data of oral anticoagulation in severe CKD (creatinine clearance [CrCl] < 25-30 mL/min). 