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Pravastatin for Primary Prevention in Older Adults: Restricted Mean Survival Time Analysis
Author(s) -
Orkaby Ariela R.,
Rich Michael W.,
Sun Ryan,
Lux Eliah,
Wei LeeJen,
Kim Dae Hyun
Publication year - 2018
Publication title -
journal of the american geriatrics society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.992
H-Index - 232
eISSN - 1532-5415
pISSN - 0002-8614
DOI - 10.1111/jgs.15509
Subject(s) - medicine , pravastatin , gerontology , survival analysis , primary prevention , cholesterol , disease
Objectives To use restricted mean survival time, which summarizes treatment effects in terms of event‐free time over a fixed time period, to evaluate the benefit of pravastatin therapy for primary prevention of cardiovascular disease in older adults. Design Secondary analysis of the Antihypertensive and Lipid‐Lowering Treatment to Prevent Heart Attack Trial‐Lipid‐Lowering Trial (ALLHAT‐LLT). Setting Ambulatory setting. Participants Individuals aged 65 and older (mean aged 71, 49% female) free of cardiovascular disease (N=2,867). Intervention Pravastatin 40 mg/d (n=1,467) versus usual care (n=1,400). Measurements We estimated the difference in RMST for total and coronary heart disease (CHD)‐free survival between the pravastatin and usual care groups over the 6‐year trial period and used parametric survival models to estimate RMST differences projected over 10 years. Results Over 6 years, individuals treated with pravastatin lived (RMST 2,008.1 days), on average, 33.7 fewer days than those receiving usual care (RMST 2,041.8 days) (difference –33.7 days, 95% confidence interval (CI)=–67.0 to –0.5 days, p=.047). Pravastatin‐treated individuals lived RMST 2,088.1 days), on average, 18.7 more days free of CHD over 6 years than those receiving usual care (RMST 2,069.4 days), but this difference was not statistically significant (difference 18.7 days, 95% CI=–10.4–47.8 days, p=.21). The 10‐year projection showed that pravastatin‐treated individuals would live 108.1 fewer days (95% CI=–204.5 to –14.1, p=.03) than those receiving usual care, although treated individuals would gain 77.9 days (95% CI=3.8–159.6, p=.046) of CHD‐free survival. Conclusion RMST provides an intuitive and explicit way to express the effect of pravastatin therapy on CHD‐free and overall survival in older adults free of cardiovascular disease. This measure allows a more personalized interpretation than hazard ratios of the benefits and risks of a medical intervention for decision‐making.