Nested Case-Control Study Using Countermatching and Its Implication in PMS Studies / 薬剤疫学

ABSTRACT

According to the on-going discussion in ICH E2E, in future PMS studies, it will be necessary to specifically address the problem and the best study method for the specified problem must be properly selected. In this article, the design for a nested case-control study using countermatching is introduced as one of the best candidate methods for future PMS studies. <BR>In the method, a cohort is stratified by the exposure status and a control is selected from the stratum with the exposure status opposite to that of the “counter-matched” case. <BR>It has been shown that this method can increase the efficiency of the study. In addition, it will give those involved in the PMS studies the confidence that the use of the nested case-control study design is valid in the PMS studies where the cohort consisting of a group of patients with the study drug and another group of those with the comparator drug is observed. <BR>However, to make this method realistic in the Japanese PMS milieu, the following two conditions must be satisfied. First, those involved in the PMS studies should realize the importance of the comparison of two drugs while the comparison of two similar drugs has been to date carefully avoided in Japanese PMS studies. Secondly, a method to identify two comparable groups should become possible. The latter may be accomplished by establishing the infrastructure for the mechanism where the prescription data in hospital/community pharmacies are used to identify those who recently started either of the two drugs compared in the study.