161. Lipids: Triglycerides – EPA and DHA Deep Dive with Dr. Erin Michos

CardioNerds Tommy Das (Program Director of the CardioNerds Academy and cardiology fellow at Cleveland Clinic) and Rick Ferraro (Director of CardioNerds Journal Club and cardiology fellow at the Johns Hopkins Hospital) join Dr. Erin Michos (Associate Professor of Cardiology at the Johns Hopkins Hospital and Editor-In-Chief of the American Journal of Preventative Cardiology) for a discussion about the effect of DHA and EPA on triglycerides and why DHA/EPA combinations may have exhibited limited benefits in trials. This episode is part of the CardioNerds Lipids Series which is a comprehensive series lead by co-chairs Dr. Rick Ferraro and Dr. Tommy Das and is developed in collaboration with the American Society For Preventive Cardiology (ASPC).

Relevant disclosures: None

Pearls • Notes • References • Guest Profiles • Production Team

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Pearls

The best intervention for heart disease is prevention! The InterHeart trial showed that 9 modifiable risk factors (dyslipidemia, smoking, hypertension, diabetes, abdominal obesity, dietary patterns, physical activity, consumption of alcohol, and psychosocial factors) predict 90% of acute myocardial infarction. So many acute events can be prevented1.Atherosclerotic vascular disease events increase across a range of triglyceride levels, even from 50-200mg/dL. So even in a relatively normal range, lower triglycerides seem to be better. Over ¼ of US adults have triglycerides over 150.While 8% of US adults take fish oil supplements, multiple meta-analyses have failed to show any benefit to the use of dietary omega-3 supplementation2. Dietary supplements these are not meant for medical use and are not studied or regulated as such!

Show notes

1. What are DHA and EPA?

DHA, or docosahexaenoic acid, and EPA, or eicosapentaenoic acid, are n-3 polyunsaturated fatty acids, also known as omega-3 fatty acids. These compounds have been of considerable interest for over two decades given observed association of high dietary omega-3 fatty acid intake with reduced cardiovascular events3. As both are important omega-3 fatty acids, trials on the benefits of DHA and EPA have often focused on the two compounds in combination.

2. What was the GISSI-Prevenzione Trial and why was it Important?

GISSI-Prevenzione trial (Lancet 1999), was one of the earliest trials to study DHA and EPA4. In this trial, the authors evaluated the effect of omega-3 supplementation as a combination pill of DHA and EPA on cardiovascular events and death in patients with recent myocardial infarction (the last three months). Over a 3.5-year follow-up period, participants treated with DHA/EPA combination experienced a significant reduction in death, nonfatal MI, and stroke.As this was an early trial, patients were largely not on statins, as these were not supported at the time of study initiation (Only 5% were on cholesterol-lowering medications at baseline, and only 45% were on cholesterol-lowering therapy at study completion). The benefits seen in this trial may not extend to modern practice with patients on contemporary background therapy.The trial participants were also not representative of our modern patients for a variety of other reasons. 85% of participants in the trial were men. 42.2% of patients in EPA/DHA arm were current smokers, and 35.4% were prior smokers. Only 14.2% of patients had diabetes and 14.7% with BMI >30.Notably, the decrease in triglycerides in this trial was only 3%, implying that triglyceride lowering did not entirely explain the benefit in cardiovascular events seen.

3. What about the data after the GISSI-Prevensione Trial?

After this positive trial for DHA/EPA in combination, subsequent trial data in support of DHA/EPA has been less robust.