Statins for Primary Prevention of Cardiovascular Events and Mortality in Older Men

Ariela R. Orkaby, MD, MPH; J. Michael Gaziano, MD, MPH; Luc Djousse, MD, ScD; Jane A. Driver, MD, MPH

Disclosures

J Am Geriatr Soc. 2017;65(11):2362-2368. 

In This Article

Results

Seven thousand two hundred and thirteen participants were eligible for analysis. At baseline statin questionnaire, 1,531 (21.2%) reported using statins >180 days in the prior year. Median age was 76.9 ± 5.2 years (min 70, max 102). Statin users were more likely to be younger, have hyperlipidemia, hypertension, and diabetes. Users were also more likely to be taking aspirin. There was no significant difference in smoking, alcohol use, or weekly exercise. Non-users were more likely to have dementia and have limitations in physical activity, such as walking, bathing, or dressing. Median time of follow up was 7.1 years (inter-quartile range 4.8–8.4), during which a total of 1,137 CV events occurred.

A total of 5,758 individuals were available for propensity score analysis, of which 1,322 reported taking a statin at baseline. The C-statistic for the PS model was 0.86. Using the ("greedy") matching method there were 1,130 matched pairs, with excellent overlap in propensity score distribution between users and non-users, and with a mean score in both groups of 0.44 (SD 0.13, P = .97). A total of 362 major CV events occurred in the PS matched cohort. Baseline characteristics are shown in Table 1. In the PS matched group, statin use was associated with an 18% lower risk of mortality, HR 0.82 (95% CI 0.69–0.98), P = .03, and a non-significant lower risk of major CV events, HR 0.86 (95% CI 0.70–1.06), P = 0.17. (Table 2 and Supplementary Appendix S2).

In secondary analyses, we separated CHD events from stroke and found no significant relationship between statin use and stroke, HR 0.70 (95% CI 0.45–1.09), P = .12; or CHD events, HR 0.95 (95% CI 0.74–1.21), P = .66. We also considered the competing risk of mortality[31] and found no evidence in our study. As age is the most important predictor of CVD, to account for a possible cohort effect we repeated our main analysis using "age with left censoring" rather than "days from baseline" as the time scale. The results were similar for major CV events, HR 0.87 (95% CI 0.71–1.07), all-cause mortality HR 0.84 (95% CI 0.85–1.01), CHD events, HR 0.92 (95% CI 0.72–1.17), and stroke, HR 0.69 (95% CI 0.44–1.08).

In subgroup analyses, we examined the cohort effect of "age at baseline," dichotomizing at median age (76), functional status, and cholesterol. Results did not change according to age category at baseline or functional status, although there was a suggestion that those who were >76 years at baseline did not benefit from statins, HR 1.14 (95% CI 0.89–1.47), compared to those who were 70–76 at baseline, HR 0.83 (95% CI 0.61–1.11), however as the confidence intervals overlap between the two groups of age, this suggests no difference between the groups. Amongst those who had elevated measured total cholesterol (>200 mg/dL) at baseline there was a statistically significant association between statin use and reduced risk of CVD events, HR 0.68 (95% CI 0.50–0.94) while those with a low total cholesterol who took statins had an increased risk of major CV events, HR 1.43 (95% CI 0.99–2.07), with overall P-interaction .003. This was not seen when we restricted the outcome to all-cause mortality (Table 3).

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