Dietary supplementation with n-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial. Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto miocardico.
Level 2 - randomized trial
Large multicenter randomized controlled trial
What was done
In a multicenter trial conducted from October 1993 to September 1995, 11,324 patients who had survived a recent myocardial infarction (within 3 months or less) were randomly assigned to receive 1 g daily n-3 polyunsaturated fatty acids (n=2,836), 300 mg daily vitamin E (alpha-tocopherol, n=2,830), both supplements (n=2,830), or no supplementation (control, n=2,828) for 3.5 years. The primary combined efficacy endpoint was death, non-fatal myocardial infarction, and stroke, evaluated by intention-to-treat analysis using both two-way factorial and four-way group comparisons.
What was found
Treatment with n-3 polyunsaturated fatty acids significantly reduced the primary composite endpoint: relative-risk decrease was 10% (95% CI 1–18) by two-way analysis and 15% (95% CI 2–26) by four-way analysis. Benefit was driven by reductions in all-cause mortality (14% decrease [95% CI 3–24] two-way; 20% decrease [95% CI 6–33] four-way) and cardiovascular death (17% decrease [95% CI 3–29] two-way; 30% decrease [95% CI 13–44] four-way). Combined treatment produced similar results to n-3 PUFA alone (14% risk decrease [95% CI 1–26] for primary endpoint; 20% decrease [95% CI 5–33] for fatal events). Vitamin E showed no statistically significant benefit.
Why it matters
This large-scale clinical trial demonstrated that post-myocardial infarction dietary supplementation with low-dose n-3 polyunsaturated fatty acids improves survival and reduces cardiovascular mortality, while clarifying that vitamin E does not confer secondary prevention benefits.
Limits
The abstract does not specify whether the trial was placebo-controlled or double-blinded, nor does it report background diet, baseline omega-3 levels, patient compliance, or adverse events. Findings are restricted to patients with recent myocardial infarction.
Cited by
- contradicts Vascepa is the only omega-3 formulation approved by the FDA for reducing cardiovascular event risk, whereas Lovaza has never been tested in a cardiovascular outcome trial.