Effects of Statin Use for Primary Prevention among Adults Aged 75 Years and Older in the National Health Insurance Service Senior Cohort (2002–2015)

BACKGROUND: This study aimed to identify adverse events and mortality in adults aged 75 years and older who were initially prescribed statins for primary prevention. METHODS: This retrospective study analyzed the data from the National Health Insurance Corporation–Senior Cohort from 2002 to 2015. An exact block matched model was constructed from statin user and statin non-user groups. RESULTS: The study sample comprised 1,370 older adults (mean age, 78 years), with 685 statin non-users matched to 685 new statin users. Compared to non-users, the adjusted hazard ratios (HRs) of new statin users were 0.83 (p=0.04) for all-cause mortality, 1.24 (p=0.03) for major adverse cardiovascular events, and 1.18 (p=0.06) for new-onset diabetes mellitus. In a sub-analysis of statin use duration, longer statin use (>5 years) was associated with a significantly lower risk of all-cause mortality (HR=0.76, p=0.01) but not with major adverse cardiovascular events (HR=0.88, p=0.36) or new-onset diabetes mellitus (HR=0.95, p=0.78) after adjusting for age, sex, body mass index, diabetes mellitus, hypertension, aspirin use, and antiplatelet use. CONCLUSION: Our findings suggested that statins started for primary prevention in older adults aged 75 years and older had an advantageous effect on all-cause mortality only if used for at least 5 years.