Effects of N-3 Fatty Acid Supplements on Clinical Outcome After Myocardial Infarction in The Elderly: Results of the OMEMI trial

Presented at the AHA Scientific Sessions 2020 by Are Annesoenn A Kalstad (Oslo, Norway)

Introduction and methods

Elderly people have a significantly increased CV risk after an acute MI compared to younger people. So, there is room for improvement in the secondary prevention of elderly patients after an MI.

Omega-3 fatty acids have the potential to offer CV protection without significant harm in vulnerable elderly patients. Therefore, the OMega-3 fatty acids in Elderly patients with Myocardial Infarction (OMEMI) trial assessed whether omega-3 fatty acid supplements reduced CV events in elderly patients with a recent acute MI.

The OMEMI trial is a multicenter, double-blind, randomized, placebo-controlled study. Patients (70-82 years) admitted to the hospital with a recent acute MI were included in the trial. Patients (n=1027) were randomized 2-8 weeks after hospitalization to 1.8 g of omega-3 fatty acid supplements daily or matching corn oil placebo. The primary outcome was a composite of non-fatal MI, unscheduled revascularization (stenting or bypass surgery), stroke, HF hospitalization, or all-cause mortality. The secondary outcome was new-onset of atrial fibrillation (AF). Safety was assessed by major bleeding outcomes. The median follow-up was 2 years.

Main results

• Supplementation of omega-3 fatty acids in MI patients had, compared to placebo, no effect on the primary CV outcome of non-fatal MI, unscheduled revascularization (stenting or bypass surgery), stroke, HF hospitalization, or all-cause mortality (HR 1.07, 95% CI:0.82-1.4, P=0.62).
• Daily intake of omega-3 fatty acids supplements had also no beneficiary effect on all-cause mortality compared to placebo (HR 1.01, 95% CI: 0.60-1.71, P=0.97).
• There was an indication of an increased risk of AF in patients taking omega-3 fatty acid supplements compared to placebo, but the difference did not reach statistical significance (HR 1.81, 95% CI:0.98-3.44, P=0.06).
• No difference in major bleeding outcomes were observed between the two groups.
• Serum measurements of EPA and DHA at baseline and end of the study showed good adherence.

Conclusion

The OMEMI trial found no positive effect of omega-3 fatty acid supplements on CV outcome and all-cause death in elderly patients after MI compared to patients receiving placebo.

Discussion

Alberico L. Catapano (Milano, Italy) proposed several theories on why discrepancies were observed between the STRENGTH and OMEMI trials compared to the REDUCE-IT trial. Firstly, icosapent ethyl (pure EPA) produced higher EPA plasma levels. Secondly, Catapano raised the point that DHA might be less biologically active or could even counteract the benefits of EPA.

Thirdly, there could be a possibility, that the mineral oil led to an unfavorable effect in the placebo group and could have exaggerated the efficacy of icosapent ethyl in the treated group, he said. Furthermore, different patient populations were enrolled in the trials. There were less CV patients in the STRENGTH trial compared to the REDUCE-IT trial (56% vs 71% respectively), but since the OMEMI trial only included CAD patients, Catapano overruled this argument immediately. Lastly, the dose could make a difference, as the availability of EPA was less in the STRENGTH trial than in the REDUCE-IT trial.

What exactly the cause of the discrepancy is at this moment is unclear, he said, but we certainly have to address the points of doses, plasma levels, as well as the effect of placebo. And a comparative clinical trial is important, bearing in mind the dose effect, and would definitely provide more clarity.

- Our reporting is based on the information provided during the AHA Scientific Sessions 2020 –