Omega-3 fatty acid supplementation not associated with lower risk of major CVD events

In a study that included nearly 70,000 patients, supplementation with omega-3 polyunsaturated fatty acids was not associated with a lower risk of all-cause death, cardiac death, sudden death, heart attack, or stroke, according to an analysis of previous studies published in the September 12 issue of JAMA.

"Treatment with marine-derived omega-3 (PUFAs) for the prevention of major cardiovascular adverse outcomes has been supported by a number of randomized clinical trials (RCTs) and refuted by others. Although their mechanism of action is not clear, their postulated effect on cardiovascular outcomes may be due to their ability to lower triglyceride levels, prevent serious arrhythmias, or even decrease platelet aggregation and . Current guidelines issued by major societies recommend their use, either as supplements or through dietary counseling, for patients after [MI; heart attack], whereas the U.S. has approved their administration only as triglyceride-lowering agents in patients with overt hypertriglyceridemia, and some (but not all) European national regulatory agencies have approved the omega-3 administration for cardiovascular risk modification. The controversy stemming from the varying labeling indications causes confusion in everyday clinical practice about whether to use these agents for cardiovascular protection," according to background information in the article.

Evangelos C. Rizos, M.D., Ph.D., of the University Hospital of Ioannina, Ioannina, Greece, and colleagues performed a large-scale synthesis of the available randomized evidence by conducting a systematic review and meta-analysis to determine the association between omega-3 PUFAs and major cardiovascular outcomes.

Of the 3,635 citations retrieved, 20 studies with 68,680 randomized patients were included, reporting 7,044 deaths, 3,993 cardiac deaths, 1,150 sudden deaths, 1,837 heart attacks, and 1,490 strokes. Analysis indicated no statistically significant association with all-cause mortality, , , heart attack, and stroke when all supplement studies were considered.

"In conclusion, omega-3 PUFAs are not statistically significantly associated with major across various patient populations. Our findings do not justify the use of omega-3 as a structured intervention in everyday clinical practice or guidelines supporting dietary omega-3 PUFA administration. Randomized evidence will continue to accumulate in the field, yet an individual patient data meta-analysis would be more appropriate to refine possible associations related to, among others, dose, adherence, baseline intake, and cardiovascular disease risk group," the authors conclude.

More information: JAMA. 2012;308[10]:1024-1033.

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AdamIsmail
not rated yet Sep 11, 2012
This was not an appropriate way to analyze an effect. Almost all of the studies included in the meta-analysis were in patients who already suffered heart attacks, and we know that studies have to be longer than two years, have a sufficient dosage (more than 1g/day), account for all the other heart disease drugs these patients are on, and also monitor the existing intakes of omega-3s from the patients' diets. Almost none of the studies included here met all these criteria, so this was definitely not the best way to measure an effect. The authors all but say that their method was not appropriate with the sentence in the last paragraph that says you will have to do a different kind of meta-analysis to determine an effect.