People with chronic kidney disease who take the blood thinner warfarin to treat a form of irregular heartbeat are at no greater risk for stroke or death than similar patients who don't take the medicine, researchers report.
The Swedish study involved more than 24,000 people diagnosed with heart disease and atrial fibrillation, a common and dangerous form of irregular heartbeat. In atrial fibrillation, blood pools in the heart's chambers, raising the risk for stroke.
Researchers led by Juan Jesus Carrero of the Karolinska Institute in Stockholm examined the link between treating atrial fibrillation with a blood thinner and patients' kidney function.
The study, published in the March 5 issue of the Journal of the American Medical Association, found that taking warfarin was associated with a lower one-year risk of death, heart attack or stroke combined, without any increase in the risk of bleeding.
This was true even in cases of severe or end-stage chronic kidney disease, Carrero's team reported.
Two experts said the type of patient described in the study requires complex management, but it seems that warfarin can safely help improve their care.
"There are complex issues related to this population of patients," said Dr. Kenneth Ong, interim chief of cardiology at the Brooklyn Hospital Center in New York City. "Patients with a history of atrial fibrillation are different from those who develop it in the course of a heart attack. Those who develop it represent a sicker group."
"The use of warfarin has been shown to be of benefit in patients who recently had a heart attack, regardless of the presence or absence of atrial fibrillation," Ong said. "Having said that, before this publication it is unclear whether this patient group as a whole would have a better outcome if they were given warfarin compared to those who did not take it."
Dr. Neil Sanghvi is a clinical electrophysiologist at Lenox Hill Hospital in New York City. He said the Swedish study shows the benefits of warfarin for this type of patient.
"Warfarin therapy should not be withheld due to the theoretical risks of bleeding given the demonstrated reduction in death, heart attacks and strokes," Sanghvi said.