Low-dose aspirin was not associated with significant reduction in total cardiovascular events in elderly patients with multiple cardiovascular risk factors according to late-breaking clinical trial research presented at the American Heart Association's Scientific Sessions 2014.

The role of aspirin in the primary prevention of cardiovascular (CV) disease has been hotly debated for several years.  Meta-analyses indicate benefits as well as risks. Recently, the US Food and Drug Administration cautioned against the general use of aspirin for the primary prevention of heart attacks and strokes.  The Japanese Primary Prevention Project (JPPP) study, prospectively evaluated daily, low-dose aspirin in the primary prevention of cardiovascular events in elderly Japanese patients with one or more risk factors for cardiovascular events but no history of atherosclerotic disease.

A total of 14,466 individuals aged 60 to 85 years with hypertension, dyslipidemia and/or diabetes mellitus who did not have a history of CV disease were randomly assigned to receive enteric-coated aspirin, 100 mg/day or no aspirin, while continuing treatment to control their risk factors. Patients were enrolled from 1007 clinics in Japan between March 20115 and June 2007. Throughout the study, 10.5% of the study population was lost to follow-up.

At a median follow-up of 5.02 years, there was no significant difference between the two groups in the number of primary events or the risk of event. The 5-year cumulative event rates were 2.772 percent for the aspirin treated group compared to 2.960 percent, for the no-aspirin group.

The primary endpoint was a composite of death from CV causes, non-fatal stroke and non-fatal MI. At 5 years there was an insignificant 6% reduction in the risk of a primary endpoint event in the aspirin group vs. the no aspirin group (p = 0.544).  No statistically significant interaction between any risk factor and treatment was observed.

When evaluating secondary endpoints, the researchers found that the rate of TIA was significantly reduced in the aspirin group (a 43% reduction, p=0.044).  Conversely, there was a significant increase in serious extracranial hemorrhage in the aspirin group − the hazard ratio indicates an 85% increase in such events (p=0.004). Therefore, the authors caution that any benefits of aspirin in terms of the reduced risk of TIA must be counterbalanced with consideration of the significantly increased risk of serious extracranial hemorrhage.

The authors conclude that aspirin was not associated with significant reduction in total cardiovascular events in elderly patients with multiple cardiovascular risk factors.

The JPPP was sponsored by the Japanese Ministry of Health, Labor, and Welfare and the Waksman Foundation of Japan. Enteric coated 100-mg aspirin tablets were provided free of charge by Bayer Yakuhin.