Benefits associated with achieving optimal risk factor levels for the primary prevention of cardiovascular disease in older men

Abstract

Background: Most incident cardiovascular disease (CVD) occurs after patients reach the age of 65. The additive benefits of aggressive risk factor management with advancing age are not well established.

Objective: To evaluate the relationship between control of four modifiable risk factors (smoking, non-high density lipoprotein cholesterol, blood pressure, and aspirin use) and risk of CVD in a primary prevention population of older men.

Materials and methods: U.S. male physicians from the Physicians' Health Study (n = 4182; an epidemiologic follow-up of a randomized trial of aspirin and beta-carotene) who in 1997 were ≥ 65 years, free of CVD and diabetes, and had a blood sample on file were studied. Cox proportional hazard models were adjusted for age and competing causes of death. The first of any CVD event, defined as cardiovascular death, nonfatal myocardial infarction, angina, coronary revascularization, nonfatal stroke, transient ischemic attack, carotid artery surgery, and other peripheral vascular disease surgery, was measured.

Results: Mean follow-up was 9.3 years, mean age was 73 years, and 96% were nonsmokers. Compared with when 4 of 4 risk factors were controlled (6.0% of participants), control of 0 of 4 risk factors almost quadrupled the risk of CVD (0.4% of participants; event rate 41.2%; hazard ratio [HR] 3.83, 95% confidence interval [95% CI] 1.72-8.55); control of 1 of 4 risk factors more than doubled the risk (14.2% of participants; HR 2.53, 95% CI 1.80-3.57); control of 2 of 4 risk factors almost doubled the risk (43.8% of participants; HR 1.94, 95% CI 1.41-2.69), and those with control of 3 of 4 risk factors also were at increased risk (35.6% of participants; HR 1.80, 95% CI 1.30-2.50). Control of each additional risk factor was associated with greater cardiovascular protection (P for trend P = .002). Depending on the number of risk factors controlled, the number-needed to control to prevent one CVD event ranged from 5 to 22.

Conclusion: Control of 4 treatable risk factors (nonsmoking, control of non-high density lipoprotein cholesterol and blood pressure, and aspirin use) was associated with substantial protection against incident cardiovascular events in older men even after adjustment for competing causes of mortality.

Trial registration: ClinicalTrials.gov NCT00000500.