NEJM Feature: Elevated risk factors can shed light on lifetime CV risk
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“The current paradigm for prevention guidelines in this country say that we should be looking at the 10-year risk for someone developing a heart attack to determine just how intensive we want to be with our therapy,” Donald M. Lloyd-Jones, MD, the study's principal investigator and chair of preventive medicine at the Northwestern University Feinberg School of Medicine in Chicago, told Cardiovascular Business. However, he said looking only at 10-year risk factors may be ineffective.
Lloyd-Jones and colleagues performed a meta-analysis—named The Cardiovascular Lifetime Risk Pooling Project—of 18 studies over the past 50 years that included 257,384 black men and women and white men and women. CV risk was measured at the ages of 45, 55, 65 and 75 years. The authors used the following risk factors: blood pressures (BP), cholesterol levels, smoking status and diabetes. During the course of the analysis, researchers estimated patients’ risk of cardiovascular (CV) events in each age category.
The researchers found that patients who held optimal risk-factor profiles (a total cholesterol level of less than 180 mg per deciliter [4.7 mmol per liter]; a BP of less than 120 mm Hg systolic and 80 mm Hg diastolic; nonsmoking status; and nondiabetic status), were at a low risk of death from CV disease through age 80.
In fact, Lloyd-Jones said that a 40-year old man who held an optimal risk-factor profile, even with elevated BP or cholesterol, would probably only have a 3 percent to 4 percent 10-year risk of developing MI. “This number is unlikely to motivate a patient to modify lifestyle or adhere to taking medication,” Lloyd-Jones added.
Additionally, those age 55 who had an optimal risk-factor profile had substantially lower risk of death from CV disease through the age of 80 compared with patients who had two or more major risk factors. For men, these numbers were 4.7 percent vs. 29.6 percent, respectively. For women, the difference was 6.4 percent vs. 20.5 percent, respectively.
Lastly, a 45-year-old man with optimal risk factors had only a 1.4 percent risk of CV disease through age 80, compared with the same age man who had two or more risk factors, resulting in a 50 percent chance of having a major event (stroke or MI) by age 80.
On the flip side, a 45-year old woman with optimal risk-factor levels would have a 4.1 percent chance of experiencing an MI or stroke; however, a woman with two or more elevated risk-factor levels at the age of 45 had a 31 percent risk of experiencing an event.
“The current study allows us to think about expanding the standard 10-year time span to think about lifetime CV,” Lloyd-Jones said. “This is a particularly useful way for us to communicate risk to patients and to understand that their risk is substantially higher when we think beyond just that 10-year risk window.”
Lloyd-Jones and colleagues reported the following conclusions:
- If a patient reaches middle age or older with all risk-factor levels being at optimal levels, the chance of encountering a CV event is “remarkably” small;
- For patients who are middle age and already have the aforementioned risk factors, the risk of encountering a CV event is “dramatically elevated;” and
- Patterns were identical for both black and white patients.
“Risk factors are universal and there was nothing unique about one group or the other,” Lloyd-Jones said. However, the researchers did find that blacks tended to have more risk factors compared with whites at any given age, “[m]eaning that their risk of developing CV disease was higher.”
For those already at risk for an event, physicians and patients must do everything they can—medical therapy and lifestyle changes—to attempt to control and reduce those risks as much as possible, he advised.
“Optimal levels will never be restored entirely, but optimal medical therapy and lifestyle changes can dramatically help to reduce the risk,” he said.
Younger patients often have optimal levels of BP, cholesterol, etc., but as they age, these levels begin to worsen and they are more at risk for diabetes and hypertension, Lloyd-Jones said.
While the news seems somewhat dismal, Lloyd-Jones said there is an upside. “If we can get more of the population to focus on healthy behaviors that will get them to middle age with optimal risk factor levels, we may be able to abolish the disease,” he said. “This is an eminently preventable disease."
Lloyd-Jones added, “Trying to preserve optimal risk-factor levels from childhood into middle age is all about lifestyle.” Because most people gain a substantial amount of weight from the age of 25 on, younger patients must focus on reducing blood pressure and cholesterol levels, eating healthy food and making good lifestyle choices from a younger age.
“If we could just get people to maintain their weight we could avoid a lot of risk factor developments,” Lloyd-Jones said. “Because once the risk factors have developed, the horse is already out of the barn.”
The researchers summed that differences in risk-factor burdens translated into differences in the lifetime risk of CV disease, which was consistent across race and birth cohorts.
The study was funded by the National Heart, Lung, and Blood Institute.