Large “real-world” study in Italy demonstrates that heart attack patients treated with 1 g/day of marine omega-3 fatty acids had much less risk of a repeat attack or sudden death compared to those who did not take omega-3s

A new, large, retrospective observational cohort study (1) conducted in five Italian health units assessed the progress of 11,269 patients 12 months after being discharged from hospital following a myocardial infarction. Some 2,425 of the patients (21.5%) had received treatment including a daily dose of marine omega-3 fatty acids ethyl esters (ca. 850 mg 2:1 DHA:EPA) originally used in the famous GISSI study (2, 3) in 1999. Despite an adherence rate of slightly less than 80%, the patients treated with marine omega-3 fatty acids had a greatly reduced risk of sudden cardiac death (HR 0.76; 95% CI 0.59 to 0.97) and recurrent acute myocardial infarction (HR 0.65; 95% CI 0.49 to 0.87). This dramatic result is similar to that seen in the original GISSI studies (2, 3) and demonstrates that the effect still exists despite the widespread use of dual antiplatelet therapy and primary and early percutaneous coronary interventions (PCIs) in the years after the original GISSI trial was conducted.

A clue as to the mechanism behind this improvement may be gleaned from a recent intervention study that used 4 g of marine omega-3 fatty acids in patients one month after their initial heart attack (4). Here, measurement of cardiac magnetic resonance demonstrated that the intervention achieved significant reductions in the left ventricular end-systolic volume index and myocardial extracellular volume fraction.

Several studies have shown the additional benefit of marine omega-3 supplementation to patients who have experienced an acute myocardial infarctions and are already being treated with statins (5,6).  The new Italian study (1) is able to corroborate these findings.

While several recent meta-analyses have cast doubt on the value of marine omega-3 fatty acids in the treatment of patients who have suffered a heart attack, this new large study from Italy (1) carried out in a “real-world” situation provides strong evidence that the current advice regarding treatment with marine omega-3 fatty acids needs to be reappraised.

1. Greene SJ, Temporelli PL, Campia U et al., "Effects of Polyunsaturated Fatty Acid Treatment on Postdischarge Outcomes After Acute Myocardial Infarction"; Am J Cardiol.2016; 117:340-346.
2. Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI); "Dietary supplementation with n-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial"; Lancet 1999; 354:447-455
3. Marchioli R, Barzi F, Bomba E et al.; "Early protection against sudden death by n-3 polyunsaturated fatty acids after myocardial infarction: time-course analysis of the results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI) - Prevenzione; Circulation 2002; 105: 1897-1903.
4. Heydari B, Abbasi SA, Shah R et al., "Effect of purified omega-3 fatty acids on reducing left ventricular remodeling after acute myocardial infarction (OMEGA-REMODEL study): a double-blind randomized clinical trial"; J Cardiovasc Magn Reson 2015; 17(S1); 7.
5. Macchia A, Romero M, D'Ettore A et al.; "Exploratory analysis on the use of statins with or without n-3 PUFA and major events in patients discharged for acute myocardial infarction: an observational retrospective study"; PLoS One 2013; 8: e62772.
6. Nishio R, Shinke T, Otake H et al., "Stabilizing effect of combined eicosapentaenoic acid and statin therapy on coronary thin-cap fibroatheroma"; Atheroscerlosis 2014; 234: 114-119.