Remnant Cholesterol Improves CV Risk Prediction

June 16, 2022

Adding remnant cholesterol to guideline prediction models should improve the identification of individuals who would benefit the most from statin treatment for the primary prevention of heart disease, a new study suggests.

The study, which followed almost 42,000 Danish individuals without a history of ischemic cardiovascular disease, diabetes, or statin use for more than 10 years, found that elevated remnant cholesterol appropriately reclassified up to 40% of those who later experienced myocardial infarction (MI) and ischemic heart disease.

"The clinical implications of our study include that doctors and patients should be aware of remnant cholesterol levels to prevent future risk of MI and ischemic heart disease," the authors conclude.

They suggest that the development of a cardiovascular risk algorithm, including remnant cholesterol together with LDL cholesterol, would help to better identify high-risk individuals who could be candidates for statins in a primary prevention setting.

They note that that physicians are encouraged to evaluate non-HDL cholesterol and/or apolipoprotein B rather than LDL cholesterol and certainly not yet remnant cholesterol, possibly because of the limited availability of remnant cholesterol values in some parts of the world.

However, they point out that remnant cholesterol can be calculated with a standard lipid profile without additional cost, which is currently already the standard procedure in the greater Copenhagen, Denmark area.

"This means that the use of remnant cholesterol is easy to introduce into daily clinical practice," they say.

The study was published online in the Journal of the American College of Cardiology on June 13.

The authors, Takahito Doi, MD, Anne Langsted, MD, and Børge Nordestgaard, from Copenhagen University Hospital, Denmark, explain that remnant cholesterol is total cholesterol minus LDL-cholesterol minus HDL-cholesterol and includes the cholesterol content of the triglyceride-rich very-low-density lipoproteins, intermediate-density lipoproteins, and chylomicron remnants in the nonfasting state.

"When these particles enter the arterial wall, they are taken up by macrophages to produce foam cells, and therefore elevated remnant cholesterol likely enhance accumulation of cholesterol in the arterial wall, leading to progression of atherosclerosis and in consequence ischemic heart disease," they note.  

They point out that most guidelines for assessment of the 10-year risk of ischemic heart and atherosclerotic cardiovascular disease include levels of total and HDL cholesterol, but remnant cholesterol levels are not included.

They conducted the current study to investigate whether elevated remnant cholesterol would lead to appropriate reclassification of individuals who later experienced MI or ischemic heart disease.

The researchers analyzed data from the Copenhagen General Population Study, which recruited individuals from the White Danish general population from 2003-2015 and followed them until 2018. Information on lifestyle, health, and medication, including statin therapy, was obtained through a questionnaire, and participants underwent physical examinations and had nonfasting blood samples drawn for biochemical measurements.

For the current study, they included 41,928 individuals aged 40-100 years enrolled before 2009 without a history of ischemic cardiovascular disease, diabetes, and statin use at baseline. The median follow-up time was 12 years. Information on diagnoses of MI and ischemic heart disease was collected from the national Danish Causes of Death Registry and all hospital admissions and diagnoses entered in the national Danish Patient Registry.

During the first 10 years of follow-up there were 1063 MIs and 1460 ischemic heart disease events (death of ischemic heart disease, nonfatal MI, and coronary revascularization).

Results showed that in models based on conventional risk factors estimating risk of heart disease of above or below 5% in 10 years, adding remnant cholesterol at levels above the 95th percentile, appropriately reclassified 23% of individuals who had an MI and 21% of individuals who had an ischemic heart disease event.

Using levels of remnant cholesterol levels above the 75th percentile appropriately reclassified 10% of those who had an MI and 8% of those who had an ischemic heart disease event. No events were reclassified incorrectly.

Using measurements of remnant cholesterol also improved reclassification of individuals with heart disease risk above or below 7.5% or 10% in 10 years.

When reclassifications were combined from below to above 5%, 7.5%, and 10% risk of events, 42% of individuals with MI and 41% with ischemic heart disease events were reclassified appropriately.

In an editorial accompanying publication of the study in JACC, Peter Wilson, MD, Emory University School of Medicine, Atlanta, and Alan Remaley, MD, National Heart, Lung, and Blood Institute, say these findings rekindle interest in atherogenic nonfasting lipid measurements and emphasize an important role for elevated nonfasting remnant cholesterol as a value-added predictor of ischemic events.

The editorialists note that both fasting and nonfasting lipid values provide useful information for atherosclerotic cardiovascular disease (ASCVD) risk estimation, and elevated nonfasting remnant cholesterol appears to help identify persons at greater risk for an initial cardiovascular ischemic event.   

They add that very elevated levels (above the 75th percentile) of nonfasting remnant cholesterol deserve further evaluation as a potentially valuable "modifier of ASCVD risk," and replication of the results could move these findings forward to potentially improve prognostication and care for patients at risk for ischemic heart disease events.

An Indirect Measure of Triglycerides

Wilson explained to | Medscape Cardiology that remnant cholesterol is an indirect measure of triglycerides beyond LDL levels, and it is thus including a new lipid measurement in risk prediction.

"We are completely focused on LDL cholesterol," he said. "This opens it up a bit by adding in another measure that takes into account triglycerides as well as LDL."

He also pointed out that use of a nonfasting sample is another advantage of measuring remnant cholesterol.  

"An accurate measure of LDL needs a fasting sample, which is a nuisance, whereas remnant cholesterol can be measured in a nonfasting blood sample, so it is more convenient," Wilson said.

While this study shows this measure is helpful for risk prediction in the primary prevention population, Wilson believes remnant cholesterol could be most useful in helping to guide further medication choice in patients who are already taking statins.

"Statins mainly target LDL, but if we can also measure nonfasting triglycerides this will be helpful. It may help us select some patients who may need a different type of drug to use in addition to statins that lowers triglycerides," he said.  

This work was supported by the Global Excellence Programme, the Research Fund for the Capital Region of Denmark, the Japanese College of Cardiology Overseas Research Fellowship and the Scandinavia Japan Sasakawa Foundation. Nordestgaard has reported consultancies or talks sponsored by AstraZeneca, Sanofi, Regeneron, Akcea, Amgen, Amarin, Kowa, Denka, Novartis, Novo Nordisk, Esperion, and Silence Therapeutics. Doi has reported talks sponsored by MSD.

J Am Coll Cardiol. Published online June 13. Abstract, Editorial  

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