The weight was the inverse of the sampling fraction of the stratified subcohort or Ni/ni where Ni and ni were the size of the entire cohort and that of the stratified sample subcohort, respectively, of the i-th statin. According to Barlow, the robust variance was used to estimate the 95% confidence interval. To adjust for confounding, the following potential confounders were included in the Cox regression model: age, gender, status of ‘‘switcher’’,GDC-0449 use of high daily dose and concomitant diseases. In addition, as an ad hoc analysis, we also estimated the hazard ratios by using all the available data in the entire cohort according to Breslow assuming that the patient was not lost to follow-up and observed for 91 days for patients who were not a case nor a subcohort member. We did not collect the latter data because the Breslow’s method was published in 2009 after the current study was started while the Barlow’s method assumed the use of the data for cases and subcohort members only. All the statistical analyses were conducted by SAS except for the analyses by the Breslow’s method where R software system was used. We examined the association between multiple events and a variety of statins by the prospective stratified case-cohort design. The use of statin had no relationship to the increased risk of our targeted events. The adjusted hazard ratio of the increase of serum creatinine for atorvastatin and fluvastatin was, however,GDC-0879 around 2.5 when pravastatin was used as a reference drug though the 95% CI was wide and inconclusive. During the last decade, results of several studies on the renal toxicity associated with the use of statin have been published. In pooled analysis of 30 clinical trials, fluvastatin was reported to be safe and effective in chronic renal disease. For atorvastatin, a beneficial effect on renal function was reported in patients with diabetes or coronary heart disease. On the other hand, in a study using the UK database, the risk for acute renal failure was increased with pravastatin and atorvastatin in males and females and fluvastatin in females, compared to no statin users.