A recent study led by Northwestern Medicine and Yonsei University in South Korea has found that more than 99% of individuals who experienced a heart attack, stroke, or heart failure had at least one risk factor above optimal levels before the event occurred. The research challenges the belief that cardiovascular disease can often strike without warning.
The study analyzed health records from over 9 million adults in South Korea and nearly 7,000 adults in the United States, following participants for up to two decades. Researchers focused on four major risk factors: blood pressure, cholesterol, blood sugar, and tobacco use. These were assessed using definitions set by the American Heart Association.
“We think the study shows very convincingly that exposure to one or more nonoptimal risk factors before these cardiovascular outcomes is nearly 100%,” said Dr. Philip Greenland, professor of cardiology at Northwestern University Feinberg School of Medicine. “The goal now is to work harder on finding ways to control these modifiable risk factors rather than to get off track in pursuing other factors that are not easily treatable and not causal.”
In both Korean and U.S. groups studied, more than 99% of those who developed coronary heart disease, heart failure or stroke had at least one nonoptimal risk factor prior to their event. More than 93% had two or more risk factors present.
High blood pressure was identified as the most common risk factor among patients—affecting over 95% in South Korea and more than 93% in the United States. Even among women under age 60—typically considered a lower-risk group—more than 95% had at least one nonoptimal factor before experiencing heart failure or stroke.
When researchers examined stricter thresholds for clinically elevated levels (such as higher cut-offs for blood pressure, cholesterol, glucose, and current smoking), they found that at least 90% of patients still had at least one major risk factor before their first cardiac event.
The findings are published in The Journal of the American College of Cardiology under the title “Very High Prevalence of Nonoptimally Controlled Traditional Risk Factors at the Onset of Cardiovascular Disease.” The research was funded by a grant from the National Research Foundation of Korea.
Dr. Greenland and his colleagues emphasize early detection and management of modifiable risks as a key strategy for preventing future cardiac events.