Neal S. Parikh, MD

In Stroke, Dr. Uchiyama and colleagues report on their investigation of aspirin for primary stroke prevention in an at-risk, elderly cohort in Japan.

The Japanese Primary Prevention Project was intended to investigate the utility of aspirin for primary prevention in an Asian population–a population thought to be at greater baseline risk of intracranial hemorrhage (ICH). In this paper, the authors present results of a post-hoc analysis regarding ischemic stroke, TIA and ICH.

The study was a nationwide, multicenter, randomized, open-label trial. Patients between the ages of 60-85 and with at least one vascular risk factor were recruited from 2005 to 2007 by primary care doctors. Patients with a prior vascular event and those with atrial fibrillation were excluded, as were those with bleeding disorders and those already on a different anti-platelet agent. Patients were randomized to 100 mg of aspirin or no aspirin.

The primary outcome was a composite of cardiovascular death, nonfatal stroke, and nonfatal MI. Ischemic stroke, ICH, TIA were among the secondary endpoints, of which ischemic stroke, TIA, and ICH are specifically discussed in this article.

Over 14,000 patients were followed for median of 5 years. The mean age was 70, and approximately 60% of patients were female. 85% of patients in both groups had hypertension, 72% had dyslipidemia, and 34% had diabetes. Self-reported adherence in the aspirin group at 5 years was 76%; adherence to the no aspirin assignment was 90%.

At 5 years, there was not a significant difference in the cumulative rate of any stroke or TIA: 2.068% in the aspirin group versus 2.299% in the no aspirin group; adjusted HR 0.927 (95% CI, 0.74-1.16). Similarly, there was not a significant difference in the individual outcomes of any stroke, ischemic stroke, and ICH. In Cox regression analysis, aspirin use was not significantly associated with cerebrovascular outcome rates.

The results are consistent with prior studies conducted in Western populations in which aspirin was not effective for stroke primary prevention. The key take home message may be the explanation of low outcome rates: aggressive risk factor management, particularly of hypertension.