Eagerly-anticipated results from one of the largest-ever studies of heart failure suggest that treatment with cheap aspirin therapy is as effective as warfarin.

Data from the the ten-year Warfarin and Aspirin for Reduced Cardiac Ejection Fraction (WARCEF) trial have been published in the New England Journal of Medicine. The head-to-head study followed 2,305 patients at 168 study sites in 11 countries on three continents and revealed that the combined risk of death, stroke, and cerebral haemorrhage was 7.47% per year for patients taking the blood-thinner warfarin and 7.93% for those on aspirin - a difference that is not statistically significant.

Patients taking warfarin had close to half the stroke risk of those taking aspirin (0.72% vs. 1.36% per year) but warfarin patients had more than twice the risk for major bleeding (1.80% vs. 0.87% per year). These results, the investigators say, cancel each other out.

However, in patients followed four years or longer, there was evidence that warfarin may be more effective in preventing the combined outcome of death, stroke, and intracerebral haemorrhage. Researchers said that follow-up analyses will further evaluate this evidence and seek to identify patients for whom one of the medications is preferred.

Principal investigator Shunichi Homma of Columbia University Medical Center/New York-Presbyterian Hospital, said that "since the overall risks and benefits are similar for aspirin and warfarin, the patient and his or her doctor are free to choose the treatment that best meets their particular medical needs. However, given the convenience and low cost of aspirin, many may go this route".

Walter Koroshetz, deputy director of the National Institute for Neurological Disorders and Stroke, part of the National Institutes of Health, said that "with at least six million Americans - and many more around the world - suffering from heart failure, the results of the WARCEF study will have a large public health impact". He added that "the key decision will be whether to accept the increased risk of stroke with aspirin, or the increased risk of primarily gastrointestinal haemorrhage with warfarin".