Atrial Fibrillation, Warfarin and Kidney Function after Heart Attack

Juan Jesus Carrero PhD (Pharm and Med) Associate Professor in Renal Medicine Karolinska Institutet, Interview with:
Juan Jesus Carrero PhD (Pharm and Med)
Associate Professor in Renal Medicine
Karolinska Institutet, Sweden. Why did you choose to study this particular question?

Answer: We chose this question because there is currently an important knowledge gap regarding safety and effectiveness of common drugs in individuals with chronic kidney disease. Because kidney dysfunction interferes with drug metabolism and drug elimination, patients with kidney dysfunction have traditionally been excluded from randomized controlled trials. Yet, practice guidelines are afterwards extrapolated to those in the absence of formal evaluation. Tell us about your study…. What did you set out to discover?

Answer: We studied outcomes associated to warfarin treatment in patients with both atrial fibrillation and kidney disease. These individuals are at a markedly increased risk of bleeding and ischemic stroke. Although such patients have a clear indication for anticoagulant therapy, recent observational studies in advanced chronic kidney disease have provided conflicting results, suggesting that warfarin treatment may instead confer harm.

Our study considered all consecutive Swedish patients with Atrial Fibrillation admitted to the hospital for an acute myocardial infarction. Because of availability of creatinine assessments, we were able to estimate the severity of underlying chronic kidney disease. Our pre-specified outcomes were the composite of death, myocardial infarction and stroke, as well as the risk of bleeding, within one year from discharge date. What were your findings?

Answer: We observed that more than 50% of the included patients were considered to have chronic kidney disease, evidencing the commonness of kidney dysfunction in individuals with cardiovascular disease.

Our main finding was that warfarin treatment was associated with a lower risk for the composite outcome without increased risk of bleeding. This was observed not only for individuals with normal kidney function but also for those with moderate, severe or end-stage kidney disease. What are the implications of the study findings?

Answer: Our study may therefore suggest that patients with Atrial Fibrillation and renal disease not requiring dialysis can also benefit from warfarin therapy and thus should not be excluded from this treatment option. What additional research is needed?

Answer: This study includes individuals with kidney disease not requiring dialysis. The evaluation of warfarin safety in dialysis patients still is not fully established. Finally, because ours is an observational study, further clinical trials are necessary to definitely answer this question.


Warfarin, Kidney Dysfunction, and Outcomes Following Acute Myocardial Infarction in Patients With Atrial Fibrillation

Juan Jesús Carrero PhD(Pharm and Med), Marie Evans MD, PhD, Karolina Szummer MD, PhD, Jonas Spaak MD, PhD, Lars Lindhagen PhD, Robert Edfors MD, Peter Stenvinkel MD, PhD, Stefan H Jacobson MD, PhD, Tomas Jernberg MD, PhD

JAMA. 2014;311(9):919-928. doi:10.1001/jama.2014.1334


Last Updated on December 21, 2014 by Marie Benz MD FAAD