Key result
Omega-3 PUFA increases new-onset atrial fibrillation risk ~90% vs placebo after myocardial infarction.
Why the study?
Recent randomized clinical trials raised concerns regarding potential adverse effects of n-3 PUFA supplementation on AF risk, prompting assessment of AF and micro-AF risk and potential mediators in post-MI patients.
Does omega-3 polyunsaturated fatty acid supplementation increase the risk of atrial fibrillation and 'micro-AF' in older patients with a recent myocardial infarction?
RCT (n=759)
Double-blind
Randomized
Yes
Does omega-3 polyunsaturated fatty acid supplementation increase the risk of atrial fibrillation and 'micro-AF' in older patients with a recent myocardial infarction?
Hazard Ratio: 1.9 (95% CI 1.16–3.11)
Absolute Event Rate: 11.9% vs 6.5%
p-value: p=0.011
Supplementation with omega-3 fatty acids post-myocardial infarction increases the risk of atrial fibrillation and micro-AF, an effect strongly mediated by increases in serum EPA levels.
Urges caution against n-3 PUFA post-MI in older adults; challenges prior safety data and extends EPA-mediated AF risk evidence.
BACKGROUND & AIMS: Recent randomized clinical trials have raised concerns regarding potential off target adverse effects from supplementation of n-3 polyunsaturated fatty acids (PUFA) on atrial fibrillation (AF) risk. We aimed to assess risk and potential mediators of AF and 'micro-AF' from n-3 PUFA in post-myocardial infarction (MI) patients. METHODS: In the OMEMI trial, 70-82 y. o. patients with a recent MI were randomized to 1.8 g/day of eicosapentaenoic-/docosahexaenoic acid (EPA/DHA) or placebo (corn oil) for two years. New-onset AF and 'micro-AF' was recorded by clinical detection and by screening with Zenicor thumb-ECG (adjudicated by blinded investigators). Serum EPA and DHA were measured at baseline and study end. RESULTS: At baseline, 759 of 1014 (75%) patients had no AF history. These patients were aged 75 ± 4 years and 71% were male. During follow-up, 43 patients developed new-onset AF (39 clinically-detected and 4 by thumb-ECG screening). In addition, 27 patients had episodes of micro-AF, yielding a total of 70 patients with new-onset AF or 'micro-AF'. In the n-3 PUFA group 46 (11.9%) had AF/'micro-AF' (28 AF, 18 'micro-AF') and in the placebo group 24 (6.5%) had AF/micro-AF (15 AF, 9 micro-AF); HR 1.90 (95%CI 1.16-3.11), P = 0.011. Changes in serum EPA (but not DHA) mediated the effect from n-3 PUFA on AF risk, explaining 65% of the association. CONCLUSION: Supplementation of n-3 PUFA post MI increases the risk of 'micro-AF' and AF, and increases in EPA seems to be an important mediator of the treatment effect from n-3 PUFA on the risk of AF. STUDY REGISTRATION: OMEMI Study; ClinicalTrails.gov identifier: NCT0184194.
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Myhre et al. (2023) conducted an RCT in Post-myocardial infarction (n=759). Omega-3 polyunsaturated fatty acids (EPA/DHA) vs. Placebo (corn oil) was evaluated on Composite of new-onset atrial fibrillation or 'micro-AF' (HR 1.90, 95% CI 1.16-3.11, p=0.011). Supplementation with 1.8 g/day of n-3 PUFA in older patients with recent myocardial infarction significantly increased the risk of new-onset atrial fibrillation or 'micro-AF' compared to placebo (HR 1.90).
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