Comparison between Japan and North America in the post-hospital course after recovery from an acute coronary event

Abstract

We compared the post-hospital prognosis after an acute coronary event (acute myocardial infarction and unstable angina) in 106 patients in Japan vs. 789 patients in North America who were prospectively enrolled in the Multicenter Study of Myocardial Ischemia and were followed-up for an average of 26 months per patients. Risk factors more frequent in Japan were older age, males and smoking at enrolment, but the rest of many risk factors were similar. After adjusting for differences in clinical and medication variables, Cox analyses indicated patients in North America had a significantly greater risk of experiencing a primary end-point (cardiac death, non-fatal myocardial infarction or unstable angina) than patients in Japan (hazard ratio [North America:Japan] = 3.1, P = 0.003). There was a non-significant trend in the restricted end-points (cardiac death or non-fatal myocardial infarction) with North America having more frequent events than Japan (hazard ratio = 2.2, P = 0.12). The long-term outcome after recovery from an acute coronary event is more favorable in Japan than in North America, mostly due to a reduction in subsequent hospitalization for unstable angina. The reason for these findings cannot be explained by differences in the measured risk factors or medications.