0404 GMT October 20, 2019
"An ever-increasing number of people reach the age of 70 without overt cardiovascular disease (CVD). This analysis suggests that improved risk prediction methods are needed to identify those who could benefit from daily low-dose aspirin," said Christopher Reid of Curtin University, Australia, sify.com wrote.
European guidelines on the prevention of CVD do not recommend aspirin for individuals free from CVD due to the increased risk of major bleeding. This advice was subsequently supported by results in moderate risk patients, diabetic patients and in people over 70 which demonstrated that modest reductions in CVD risk were outweighed by the increased bleeding hazard.
The primary finding from the study's randomized trial was that in people aged 70 years or over with no known CVD, there was no effect of 100 mg of daily aspirin on the composite primary endpoint of disability-free survival (defined as those not reaching a primary endpoint of dementia or persistent physical disability or death).
This analysis examined whether the results for the primary endpoint of disability-free survival might vary by the baseline level of CVD risk.
Analyses were also conducted for the secondary endpoints of all-cause mortality, major hemorrhage, and prevention of CVD.
The investigators calculated ten-year CVD risk probabilities at baseline for the 19,114 participants using the Framingham score (up to 75 years) and the atherosclerotic cardiovascular disease (ASCVD) pooled cohort risk equations (up to 79 years) and divided them into thirds.
As there is no CVD risk scores available beyond the age ranges specified in the equations, they also classified participants according to the presence of 0 to 1, 2 to 3, or more than three CVD risk factors. Overall rates of disability-free survival, mortality, major bleeding, and CVD were examined for each risk group and outcomes were compared for those treated with aspirin or placebo.
For participants in the lowest third of CVD risk, by both Framingham and ASCVD scores, there was no disability-free survival or cardiovascular benefit from aspirin. This group also had the highest likelihood of bleeding.
In contrast, those in the highest third of CVD risk, by both Framingham and ASCVD scores, had significantly lower CVD event rates on aspirin with similar rates of bleeding. Hazard ratios for CVD reduction with aspirin version placebo were 0.72 for those defined as high risk by the ASCVD equations.
However, this reduction in CVD did not translate to a significantly improved disability-free survival. Hazard ratios for disability-free survival with aspirin versus placebo were 0.86 for the group designated high risk by the Framingham score and 0.89 for those considered high risk by the ASCVD equations.
"The findings emphasize that the risk-benefit trade-off for aspirin use in healthy older men and women varies across levels of cardiovascular risk, said Reid.