November 17, 2014
Science Daily/JAMA - Journal of the American Medical Association
Researchers examined whether once-daily, low-dose aspirin would reduce the total number of cardiovascular (CV) events (death from CV causes, nonfatal heart attack or stroke) compared with no aspirin in Japanese patients 60 years or older with hypertension, diabetes, or poor cholesterol or triglyceride levels.
The World Health Organization estimates that annual global mortality due to cardiovascular diseases (including heart attack and stroke) will approach 25 million by 2030. A recent study of trends in cardiovascular disease in Japan indicated that there has been, from 1960 to 2000, a steep increase in the prevalence of glucose intolerance, hypercholesterolemia, and obesity, probably due to the adoption of Western diets and lifestyles. By 2030, it is estimated that 32 percent of the Japanese population will be 65 years or older. Prevention of atherosclerotic cardiovascular diseases is an important public health priority in Japan due to an aging population, according to background information in the article.
This study included 14,464 patients (60 to 85 years of age) with hypertension, dyslipidemia (poor cholesterol or triglyceride levels), or diabetes mellitus who were randomized to aspirin (100 mg/d) or no aspirin in addition to ongoing medications. The patients were recruited by primary care physicians at 1,007 clinics in Japan. The study was terminated early by the data monitoring committee after a median follow-up of 5.02 years based on likely futility.
The researchers found that there was no statistically significant difference between the two groups in time to the primary end point (a composite of death from cardiovascular causes, nonfatal stroke, and nonfatal heart attack). At 5 years after randomization, the cumulative primary event rate was similar in participants in the aspirin group (2.77 percent) and those in the no aspirin group (2.96 percent).
Aspirin significantly reduced incidence of nonfatal heart attack and transient ischemic attack, and significantly increased the risk of extracranial hemorrhage requiring transfusion or hospitalization.
The authors write that despite inconsistent evidence for the benefit of aspirin in primary prevention of cardiovascular events, the benefits in secondary prevention are well documented, including in Japanese patients. "There is also a growing body of evidence to suggest benefits for aspirin in the prevention of colorectal and other cancers, and the prevention of cancer recurrence, including in the Japanese population. Reduction in the incidence of colorectal cancer may influence the overall benefitrisk profile of aspirin. Further analyses of [this] study data are planned, including analysis of deaths associated with cancers, to allow more precise identification of the patients for whom aspirin treatment may be most beneficial."