Identification of subgroups within a Japanese older adult population for whom statin therapy is effective in reducing mortality

Use of statins for primary prevention can reduce all-cause mortality in Asian elderly populations, but their effect and the specific effective subgroups in the elderly Japanese population remain unclear. This study examined the relationship between statin therapy for primary prevention and mortality reduction in older Japanese adults, and investigated the effective subgroups. The cohort study was conducted using the Shizuoka Kokuho Database (SKDB). Data were compared between the statin-treated group and a non-statin-treated (control) group using the inverse probability of treatment weighting (IPTW) method. In the SKDB cohort aged ≥65 years, new statin use was associated with a decreased risk of all-cause mortality (hazard ratio, 0.40; 95% confidence interval [CI], 0.33–0.48) after IPTW adjustment. The risk difference for mortality at 5 years in the statin-treated group compared with that in the control group was 0.05 (95% CI, 0.04–0.06), and the number needed to treat was 21.20 (95% CI, 18.10–24.70). In conclusion, statin use for primary prevention in older adults may reduce the risk of all-cause mortality in the population without atherosclerotic disease. Furthermore, statin use for primary prevention is feasible in patients aged 75 to