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Word of the Day

Omega-3s do not prevent CV disease

Clinical Question:
Does omega-3 fatty acid supplementation prevent future cardiovascular events in patients with preexisting cardiovascular disease?

Bottom Line:
Supplementing with omega-3 fatty acids does not decrease the likelihood of a subsequent cardiovascular event in patients with preexisting cardiovascular disease over the course of 1 year. (LOE = 1a)

Kwak SM, Myung SK, Lee YJ, Seo HG, for the Korean Meta-analysis Study Group. Efficacy of omega-3 fatty acid supplements (eicosapentaenoic acid and docosahexaenoic acid) in the secondary prevention of cardiovascular disease. A meta-analysis of randomized, double-blind, placebo-controlled trials. Arch Intern Med 2012;172(9):686-694.  [PMID:22493407]

Study Design:
Meta-analysis (randomized controlled trials)

Self-funded or unfunded

Various (guideline)

The authors conducting this meta-analysis searched several databases, including the Cochrane Library, and identified 14 studies enrolling a total of 20,485 patients with a history of cardiovascular disease. The patients to were randomized to receive omega-3 supplements for 1 year in most studies (the longest study lasted 5 years). Two investigators independently selected studies for inclusion. Study quality was assessed with the frequently used Jadad scale, which found most studies to be of high quality. The authors found homogeneity among most of the studies and no evidence of publication bias. They used the "all bad things" outcome as their primary measure to determine whether patients were less likely to experience one of a number of cardiovascular outcomes ranging from more important -- cardiovascular death, stroke, myocardial infarction -- to less important, such as tranisent ischemic attack, angina, and peripheral vascular disease. Mixing these apples and oranges could affect the statistics. Supplementation did not reduce the risk of overall cardiovascular events. Individually, the only outcome that was significantly affected was cardiovascular death, though this effect was lost when a single study with possible methodologic problems was removed from the analysis. Results did not differ when the authors analyzed the results by dose of the supplement, duration of follow-up, or study quality.


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