November 6, 2013
British Review Advises Caution in Using Aspirin for
Disease Prevention

Coventry, UK—Do the benefits of daily aspirin use really outweigh the risks in patients who are at risk of developing cardiovascular disease or colorectal cancer but have not yet done so?

There is no one-size-fits-all answer, according to the authors of a British study. Because of the potential for adverse side effects, they urge caution about the widespread use of aspirin for individuals who are as yet free of disease.

The comprehensive risk and benefit review of randomized controlled trials available as of June 2012 was conducted by researchers at Warwick Medical School and published by Britain’s National Institute for Health Research Health Technology Assessment (NIHR HTA) Programme.

The Warwick researchers found that the reported benefits of taking aspirin each day ranged from a 10% reduction in major cardiovascular events to a 15% drop in total coronary heart disease. In real terms, study authors note that would translate to 33 to 46 fewer deaths per 100,000 patients using the therapy. As for colorectal cancer, the analysis found reported reductions beginning about 5 years after treatment initiation and resulting in 34 fewer deaths from colorectal cancer per 100,000 patients.

On the other hand, daily dosing of aspirin increased gastrointestinal bleeding 37%, essentially an extra 68 to 117 occurrences per 100,000 patients, and between a 32% to 38% increase in the likelihood of a hemorrhagic stroke, or about an extra 8 to 10 occurrences per 100,000 patients, according to the report.

“This study looks deeper into the range of research on regular aspirin use than anything before, using more innovative methods, and it makes it clear that there is an incredibly fine balance between the possible benefits and risks of the intervention,” said Aileen Clarke, MD, professor of Public Health Research and director of Warwick Evidence at Warwick Medical School. “We need to be extremely careful about over-promoting aspirin intervention without having first fully understood these negative side effects.”

The study notes, “No guidelines currently recommend the routine use of aspirin across the adult population for the primary prevention of either cancer or CVD. Recommended usage among higher-risk populations critically depends on definitions of ‘higher’ risk, and these vary considerably.”

Clarke added that several ongoing trials coming to completion in the next 6 years “may help to clarify this further, including the impact of different dose regimens.”

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