[Clinical studies for acute coronary syndrome, the comparison among Western countries and Japan]

In this report, concepts of randomized controlled trial and cohort study were explained, and also an outline about difference of randomized clinical trial and registry study for the treatment and assessment of acute coronary syndrome was explained. Two studies of JEPPORT and JAPAN-ACS were introduced as subjects and argued. Randomized controlled trials involve.special inclusion and exclusion criteria. So, the phenomena observed in these clinical trials do not always explain clinical practice in the real world. On the other hand, in registry studies, all typical patients are covered, thus better reflecting the clinical practice. In this respect, the phenomena found in the registry studies consider to have complimentary value.