Juan Jesus Carrero, Ph.D., of the Karolinska Institutet, Stockholm, and colleagues examined outcomes associated with warfarin treatment in relation to kidney function among patients with established cardiovascular disease and atrial fibrillation. Using data from a Swedish registry, the study included survivors of a heart attack with atrial fibrillation and known measures of serum creatinine (n = 24,317; a substance used to measure kidney function), including 21.8 percent who were prescribed warfarin at discharge.
About 52 percent of patients had moderate chronic kidney disease (CKD) or worse. The researchers found that warfarin treatment was associated with a lower l-year risk of a composite of the outcomes of death, heart attack, and ischemic stroke without a higher risk of bleeding. This association was observed in patients with moderate, severe, or end-stage CKD. The number of patients who developed the composite outcome, bleeding events, and the total of these 2 outcomes increased with the worsening of CKD categories, as did the rate at which these events occurred.
Wolfgang C. Winkelmayer, M.D., M.P.H., Sc.D., and Mintu P. Turakhia, M.D., M.A.S., of the Stanford University School of Medicine, Palo Alto, Calif., (Dr. Winkelmayer is also an Associate Editor, JAMA), comment on the findings of this study in an accompanying editorial.2
“In conclusion, the study by Carrero et al in this issue of JAMA provides the best evidence to date that vitamin K antagonists [anticoagulants] are associated with improved clinical outcomes and no significant increased risk of bleeding in patients with myocardial infarction and atrial fibrillation with advanced CKD.”