Physicians' Academy for Cardiovascular Education

Low-dose aspirin is not effective as primary CV prevention in Japanese elderly

News - Nov. 17, 2014

 
Low-Dose Aspirin for Primary Prevention of Cardiovascular Events in Elderly Patients With Multiple Atherosclerotic Risk Factors: A Randomized Controlled Trial

 
Presented at the AHA congress 2014 by: Yasuo Ikeda (Shin-oyama City Hospital, Tochigi, Japan)

LBCT.02 - Anti-Lipid Therapy and Prevention of CAD

 

Background

The World Health Organisation has predicted that the annual global mortality as a consequence of cardiovascular (CV) disease (including myocardial infarction and stroke) will approach 25 million in 2030. Prevention of atherosclerotic CV disease is therefore a priority in Japanese public health, as a consequence of the aging population and adoption of Western diet and lifestyle.
This study therefore aimed to examine if daily low-dose aspirin can reduce the incidence of CV events in elderly Japanese patients with atherosclerotic risk factors. The Japanese Primary Prevention Project was a multicentre study based on the Prospective Open Blinded Endpoint (PROBE) study design. 14.464 patients were recruited by primary care physicians, and followed for up to 6.5 years (median follow-up: 5.02 years, IQR: 4.55-5.33). Patients presented with hypertension, dyslipidaemia and/or diabetes mellitus, and were randomised to enteric coated aspirin 100 mg once daily or no aspirin, in addition to current therapy.

 
Main results

  • No difference was seen between the treatment groups in the occurrence of the primary endpoint of death by CV causes, non-fatal stroke and non-fatal MI (event rate over 5 years: 2.77% with aspirin vs. 2.96% without, HR: 0.94, 95%CI: 0.77-1.15, P=0.544).
  • No differences were seen in the primary endpoint in different risk factor sub groups.
  • Only with regard to the secondary endpoint of non-fatal MI a benefit was seen of aspirin, yielding an event rate over 5 years of 0.30% as compared with 0.58% without aspirin (HR: 0.53, Wald 95%CI: 0.31-0.91, P=0.019) and with regard to the occurrence of TIA (event rate over 5 years: 0.26% vs. 0.49%, HR: 0.57, Wald 95%CI: 0.32-0.99, P=0.044).
  • More serious extracranial bleedings needing transfusion or hospital admission were needed with aspirin use (event rate over 5 years:  0.86% vs. 0.51%, HR: 1.85, 95%CI: 1.22-2.81, P=0.004).
  • Multiple gastrointestinal side-effects of interest occurred more with aspirin use.
 

Conclusion

This study shows that elderly Japanese patients with CV risk factors do not benefit from daily low-dose aspirin to reduce the general risk of atherosclerotic events. It should be noted that the study was stopped prematurely (at 400 events instead of the estimated 624), thus it is possible that the findings are the result of a lack of power. In any case, the clinical use of aspirin for the primary prevention of CV events in this patient population is lower than anticipated.
Aspirin did lower the incidence of non-fatal MI and TIA, but it increased the number of extracranial bleedings.

This article was published in JAMA on November 17.

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