People with high levels of triglycerides (fats in the blood) are at elevated risk for cardiovascular disease. High doses of long-chain omega-3 fatty acids (EPA and DHA) can lower elevated triglycerides by 50 percent or more; thus the FDA has approved several prescription drugs containing purified omega-3s for the treatment of triglyceride levels above 500 mg/dL. Now a major clinical trial, published in the New England Journal of Medicine in November 2018, has shown that one of these omega-3 drugs, called Vascepa and containing only concentrated EPA, can actually reduce the risk of heart attacks, strokes, and other cardiovascular events in people at high risk.
The study, called REDUCE-IT, involved 8,179 people, average age 64, who had high triglycerides (average 216 mg/dL; an ideal level is less than 100) and either established cardiovascular disease or else diabetes plus at least one other cardiovascular risk factor. At the start, they had low LDL (“bad”) cholesterol levels (average 75 mg/dL) as a result of statin treatment. Half took Vascepa (4 grams a day) plus their statin, the other half a placebo plus statin.
After five years, the Vascepa group had 25 percent fewer major cardiovascular events than the placebo group. That worked out to about one less event per 20 people. The observed benefit was seen regardless of the participants’ triglyceride levels (at baseline or after treatment), suggesting that other mechanisms besides triglyceride lowering, such as anti-inflammatory effects, could have contributed to the benefit. The Vascepa group had slightly more hospitalizations for atrial fibrillation.
Because Vascepa is the only drug containing just EPA (no DHA), it is not known if other omega-3 drugs would have the same benefits. As of late 2018, the FDA had not yet reviewed data from the study or approved Vascepa for use in this high-risk population, though doctors may prescribe it for them off-label.
One lingering question about the study was its use of mineral oil in the placebo capsules, which may have reduced statin absorption in some participants, thus raising average LDL cholesterol slightly—though the small difference in LDL levels between the groups would be unlikely to explain an observed benefit of this magnitude, the researchers noted.
Also see VITAL News About Vitamin D and Omega-3s.