This was probably because we obtained minimum amount of information except for the cases and subcohort members. This study has some limitations. New statin use in this study might not be perfectly representative of statin use in entire country. However, the distribution of prevalent users of statin in 68 hospitals was almost the same with that in the whole nation. Second, pediatric patients were included in this study and the study population may not be homogenous. However, the number of pediatric patients was 10 in entire cohort and 2 in subcohort and the effect of the inclusion of pediatric patients on the results would be minimal. Third, during the 3-month follow-up period,FDA-approved Compound Library the proportion of those who had blood test and urine test was less than 100% though the proportion was similar between statins. Fourth, some events associated with a drug may occur late and the follow-up period longer than 3-month may be needed to know the occurrence of such events. However, most of renal, liver and muscle events had occurred within the 12-week observation period in a DUI conducted in Japan. For short-term outcomes like in our study, the 3- month follow-up may be therefore adequate. Fifth,FG-4592 this study had insufficient statistical power to detect the association between use of statin and renal, liver and muscle events. The sample size was smaller than initially planned and the 95% CI of the hazard ratio was wide for most events though all the cases were carefully adjudicated by the event review committee. Lastly, the inclusion of the ‘‘switchers’’ in the study population may have impeded the estimation of the correct estimates of the risk as the ‘‘switchers’’ may be regarded as a non-new user of a drug class of lipidlowering drugs. However, the proportion of the ‘‘switchers’’ was relatively small and the results were essentially the same even when excluding the ‘‘switchers’’ in the analysis. Stxs are a family of protein toxins that share a structure of polypeptide subunits consisting of an enzymatically active A subunit that is linked to a pentamer of B subunits.