A Kiwi study has found the number of heart attacks or strokes prevented by prescribing aspirin to high risk patients is likely to outweigh the risks of bleeding.
But the University of Auckland researchers are also advising a cautious approach to prescribing aspirin to people aged 60-69 years when other factors also needed to be considered.
The Health Research Council-funded research was published today in the New Zealand Medical Journal using data from the PREDICT cohort study – a study analysing ongoing data gathered using the PREDICT cardiovascular disease (CVD) risk prediction tool involving more than 400,000 New Zealanders.
The study authors’ says there remains some uncertainty about whether aspirin should be used to prevent someone having a first CVD event (i.e. a heart attack or stroke) because while aspirin reduces CVD risk it also increases the risk of bleeding – particularly from the gastrointestinal tract.
The current New Zealand recommendations are to consider prescribing aspirin for people under 70 who have a high (15% or greater) risk of having a first CVD event within the next five years. Prescribers are also recommended to assess and discuss the potential benefits and harms with patients but no resources were available to support this decision-making process.
The researchers used the PREDICT cohort study data to model the relative CVD or bleeding risk for male and female patients aged 40-80 with varying levels of CVD risk from low to very high. They then compared the results for if the patient group already was using other medication successfully to lower their cholesterol and blood pressure and or if they were only taking aspirin.
The results found that on average the number of CVD events avoided by taking aspirin was likely to exceed the harm of bleeding in people meeting the risk criteria for being prescribed aspirin.
However they said the results also indicated caution was needed in prescribing aspirin to people aged 60-69 years, especially if they did not already have their cholesterol- and blood pressure-lowering medication optimised, or if they had other bleeding risk factors, such as diabetes or smoking.