Aspirin failed to reduce events in older Japanese patients

CHICAGO — Daily, low-dose aspirin did not decrease long-term atherosclerotic events compared with no aspirin use in a study of elderly Japanese patients with CV risk factors.

“The clinical importance of aspirin in the primary prevention of cardiovascular events is less than originally anticipated in this patient population,” Kazuyuki Shimada, MD, from the Shin-Oyama City Hospital, Tochigi, Japan, said during a presentation.

Shimada and colleagues enrolled 14,464 patients aged 60 to 85 years at 1,007 clinics in Japan from March 2005 to June 2007 in the Japanese Primary Prevention Project. Patients presented with hypertension, dyslipidemia and/or diabetes, and were randomly assigned in a 1:1 ratio to receive enteric-coated aspirin 100 mg once daily (n=7,220; mean age, 70.6 years) or no aspirin (n=7,244; mean age, 70.5 years) in addition to ongoing medications to control their conditions. A blinded multidisciplinary expert panel adjudicated study outcomes.

At a median follow-up of 5 years, the primary composite endpoint, which included death from CV causes, nonfatal stroke and nonfatal MI, was similar between the groups (aspirin, 2.77% vs. no aspirin, 2.96%; HR=0.94; P=.544).

Secondary endpoint analysis showed no significant differences in death from CVD (aspirin, 0.86% vs. no aspirin, 0.78%; HR=1.03; P=.889) and nonfatal cerebrovascular disease (aspirin, 1.65% vs. no aspirin, 1.64%; P=.780) between the groups; however, the researchers observed a reduction in the rate of nonfatal MI among patients assigned aspirin (0.3% vs. 0.58%; HR=0.53; P=.019).

According to Shimada, the study was discontinued prematurely before the primary endpoint events were adequate for the study to reach statistical power, as only 400 of the estimated 624 events had occurred. “Therefore, the possibility that aspirin does have a beneficial effect cannot be excluded,” he said.

Shimada added that future analyses are planned to identify the subgroups of patients who may benefit most from aspirin and determine whether aspirin is associated with prevention of some cancers. – by Brian Ellis

For more information:

Shimada K. LBCT.02: Anti-Lipid Therapy and Prevention of CAD. Presented at: American Heart Association Scientific Sessions; Nov. 15-19, 2014; Chicago.

Ikeda Y. JAMA. 2014;doi:10.1001/jama.2014.15690.

Disclosure: Shimada reports financial disclosures with Daiichi-Sankyo, Dainippon Sumitomo Omron, Shionogi and Takeda.