It has been suggested that the failure of secondary prevention trials to show a beneficial effect of n-3 fatty acids on cardiovascular outcomes may be due to the growing use of statins. This study assessed whether statins modify the effects of n-3 fatty acids on major adverse cardiovascular events in patients with a history of myocardial infarction (MI).

Data were analysed on patients who participated in the Alpha Omega Trial who were divided into consistent statin users (n = 3740) and consistent statin non-users (n = 413). The effects of an additional daily amount of 400 mg eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA), 2 g α-linolenic acid (ALA), or both on major cardiovascular events were evaluated.

The following findings were evaluated:

• 495 (13%) statin users and 62 (15%) statin non-users developed a major cardiovascular event.

• In statin users, an additional amount of n-3 fatty acids did not reduce cardiovascular events [Hazard Ratioadj 1.02; 95% CI; 0.80, 1.31; p = 0.88].

• In statin non-users, 9% of those who received EPA–DHA plus ALA experienced an event compared with 18% in the placebo group (HRadj 0.46; 95% CI: 0.21, 1.01; p= 0.051).

The researchers conclude from these findings that in patients with a history of MI who are not treated with statins, low-dose supplementation with n-3 fatty acids may reduce major cardiovascular events; this suggesting that statin treatment modifies the effects of n-3 fatty acids on the incidence of major cardiovascular events.