Tool makes taking aspirin safer

Researchers have developed a new tool that could make the humble aspirin a safer, bettertargeted preventive for heart disease and stroke.

Thousands of New Zealanders take aspirin long-term to reduce their risk of cardiovascular disease (CVD) but the drug’s bloodthinning action carries its own risk – potentially fatal internal bleeding.

This risk varies from person to person and until now, doctors had no way of assessing an individual patient’s risk. However, researchers from the University of Auckland’s Faculty of Medical and Health Sciences and Middlemore Hospital have found a way to do just that.

The team, led by senior lecturer Dr Vanessa Selak, developed personalised bleeding risk models that estimate a person’s future risk of a major bleed.

This can then be used to predict a person’s additional bleed risk if they start taking aspirin.

Their research was published in the Annals of Internal Medicine journal yesterday.

For people who have already had a heart attack or stroke, the benefit of aspirin in reducing CVD generally outweighed its harms in increasing bleeding, Selak, from the Department of Epidemiology and Biostatistics in the School of Population Health, said. ‘‘However, guidelines are unclear in people who are at high risk of having their first heart attack or stroke.’’

To identify the extra bleed risk, researchers worked out the baseline risk of major bleeds (that resulted in hospitalisation or death) in people at high risk of CVD not already taking aspirin. They crunched data from more than 350,000 people aged 30 to 79 who had seen their GP or practice nurse for a CVD risk assessment between 2002 and 2015.

Health Ministry data allowed researchers to track those people anonymously. By linking this data, the researchers found the original pool of people went on to have 4442 major bleeds, of which 313 (7 per cent) were fatal. They identified several risk factors for CVD that were also risk factors for major bleeds, including older age, smoking, diabetes, ethnicity, deprivation, and use of blood pressure-lowering medication.

Selak said the researchers’ next step was to develop a ‘‘calculator’’ that integrated the benefits and harms to prevent CVD. The calculator could be available by the end of the year.

The research was funded by the Health Research Council.

For people who have already had a heart attack or stroke, the benefit of aspirin . . . generally outweighed its harms.