Polyunsaturated fatty acids derived from fish oils have been shown to confer benefit following myocardial infarction, and in patients with heart failure. They are thought to be pleiotropic, effecting atherosclerosis, inflammation, thrombosis and arrythmogenesis with a minimal side effect profile. However, the role of these potentially attractive drugs in primary prevention remains unknown.

In this double-blind, placebo-controlled primary care based clinical trial, 12,513 patients with multiple cardiovascular risk factors or atherosclerotic vascular disease who had not had a myocardial infarction were recruited and randomly assigned in a 1:1 ratio to n-3 fatty acids (1 g daily) or placebo (olive oil) and followed for a median of 5 years. The initially specified primary end point was the cumulative rate of death, nonfatal myocardial infarction, and nonfatal stroke. At 1 year, after the event rate was found to be lower than anticipated, the primary end point was revised as time to death from cardiovascular causes or admission to the hospital for cardiovascular causes. The results demonstrated no benefit for the intervention group with the primary end point occurring in 733 (11.7%) of those assigned to n-3 fatty acids and 745 (11.9%) of those receiving placebo (adjusted HR, 0.97; 95% CI, 0.88 to 1.08; P=0.58). The same results were observed for all the secondary endpoints.

Conclusion:

In a large, prospective, double-blind study of patients with multiple cardiovascular risk factors, primary prevention by daily treatment with n-3 fatty acids did not reduce cardiovascular mortality and morbidity.

• Roncaglioni MC, Tombesi M, Avanzini F, Barlera S, Caimi V, Longoni P, Marzona I, Milani V, Silletta MG, Tognoni G, Marchioli R. n-3 fatty acids in patients with multiple cardiovascular risk factors. N Engl J Med. 2013 May 9;368(19):1800-8.