Recently, a Swedish prospective national cohort study published online by JAMA showed that treatment with warfarin reduced the incidence of death, recurrent MI, and ischemic stroke (a composite endpoint) after episodic acute myocardial infarction (MI) with atrial fibrillation in all severity categories of chronic kidney disease (CKD) patients. Warfarin did not lead to an increased risk of bleeding while providing this benefit during the 1-year follow-up period. The study, conducted by Juan Carrero, MD, of the Karolinska Institutet’s Center for Molecular Medicine, and colleagues, found that in patients with acute myocardial infarction combined with atrial fibrillation, warfarin reduced the 1-year incidence of the composite endpoint of death, infarction, and ischemic stroke but did not increase the risk of bleeding, and was not associated with the severity of chronic kidney disease. The study included 24,317 survivors of acute myocardial infarction (combined atrial fibrillation and known blood creatinine levels) through an observational prospective analysis of data from the SWEDEHEART program from 2003-2010. Of all study participants, 5,292 (21.9%) were treated with warfarin. During follow-up, 9002 composite endpoint events occurred: 3551 deaths, 4573 recurrent MIs, and 878 ischemic strokes. The results showed that across all CKD severity categories, the rates of death, MI, and ischemic stroke were 5.8%, 2.2%, and 1.8% lower, respectively, in patients on warfarin than in those not on warfarin. However, the relative risk of bleeding events was not significantly higher in the warfarin group than in the non-warfarin group, regardless of CKD severity.