A new study led by researchers at Massachusetts General Hospital in Boston recently showed that the new guidelines issued in 2013 concerning statin based therapy are better than the previous guidelines in identifying cardiovascular risk. The study was recently published in the journal JAMA and is entitled “Guideline-Based Statin Eligibility, Coronary Artery Calcification, and Cardiovascular Events.”
Statins are a medication approved by the Food and Drug Administration (FDA) for hypercholesterolemia (high cholesterol levels) due to their ability to inhibit cholesterol biosynthesis. Statins have also been shown to have other clinical benefits, namely immunomodulatory and anti-inflammatory properties. Hypercholesterolemia is associated with an increased risk for cardiovascular events and cardiac mortality.
The 2013 American College of Cardiology/American Heart Association (ACC/AHA) guidelines for the management of cholesterol established new eligibility criteria for statin therapy. However, it is not clear if these new criteria improve the identification of individuals at higher cardiovascular risk.
The goal of the study was to compare the new 2013 ACC/AHA guidelines to the previous 2004 guidelines issued by the National Cholesterol Education Program Updated Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (ATP III), in terms of the ability to identify individuals with cardiovascular disease and/or coronary artery calcification (CAC), a condition where calcium deposits accumulate in the coronary arteries that can lead to heart attack.
The team analyzed data from children and grandchildren of participants in the Framingham Heart Study, a project started in 1948 with participants from the town of Framingham, Massachusetts, which was focused on the identification of risk factors for cardiovascular diseases. The participants enrolled in the study were aged 35 or older in the case of men, and 40 or older in the case of women. Participants had no known cardiovascular disease, and had undergone a cardiac computed tomography (CT) scan between 2002 and 2005. Researchers analyzed how well both criteria sets predicted cardiovascular risk up to 2013.
Researchers found that among the 2,425 participants who had never received statin therapy, 39% were eligible to treatment by the ACC/AHA criteria in comparison to 14% by the ATP III criteria. Surprisingly, within these groups, a similar percentage of actually experienced cardiovascular events were found, being 6.3% in patients who met the ACC/AHA criteria and 6.9% for those who met ATP III criteria. The team also reported that the ACC/AHA criteria were better in identifying individuals with a low risk of cardiovascular events in comparison to ATP III criteria.
“Using 10-year follow-up data from asymptomatic patients enrolled in the Framingham Heart Study, our paper demonstrates that these new guidelines – which represent a shift in the treatment approach for primary prevention of cardiovascular disease — indeed improve identification of adults at higher risk for future cardiovascular events who were not captured by previous guidelines,” noted the study’s senior author Dr. Udo Hoffmann in a news release. “Extrapolating our results to the approximately 10 million U.S. adults who would be newly eligible for statin therapy under the new guidelines, we estimate that between 41,000 and 63,000 cardiovascular events – heart attacks, strokes or deaths from cardiovascular disease – would be prevented over a 10-year period.”
Regarding CAC, cardiac CT scans revealed that 42% of the participants had CAC with 8% having high levels. Researchers found that these participants were more likely to be eligible to statin therapy through the ACC/AHA (85%) than by the ATP III criteria (34%).
“Our study shows that the ACC/AHA guidelines for statin eligibility aligned with risk levels indicated by CAC scores much better than the ATP III guidelines, providing a potential explanation for the improved prediction of cardiovascular risk,” explained Dr. Hoffmann. “However, 93 percent of those designated statin-eligible by ACC/AHA criteria would not be expected to have a cardiovascular event during the next 10 years, while nearly 30 percent of those with coronary calcification would not be captured by the new guidelines as statin eligible. That indicates that calcium scoring could be used to further improve our ability to identify people at truly high or low risk for cardiovascular events.”
The research team concluded that the new ACC/AHA guidelines are more accurate and efficient than the previous ATP III guidelines in identifying the risk of cardiovascular events and statin eligibility. This is important as it allows a reliable distinction between patients that require statin therapy due to an intermediate to high risk for cardiovascular events and patients with low risk, avoiding in this case unnecessary treatment.