Effects of Omega-3 Fatty Acid Treatment on Risk for Atrial Fibrillation: An Updated Meta-Analysis of 35 Trials including 114 592 Individuals.

BACKGROUND

Recent meta-analyses of randomized controlled trials have raised concerns that treatment with omega-3 fatty acids may increase the risk of atrial fibrillation (AF). However, these meta-analyses included at most 8 trials. The aim of this current meta-analysis was to expand the search by including other eligible omega-3 randomized controlled trials with AF incidence data, incorporating both published and unpublished data.

METHODS

Eligible studies were randomized controlled trials investigating daily doses of ≥500 mg/d of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Additional inclusion criteria included ≥12 months of treatment with EPA/DHA, participants ≥50 years of age, and, where possible, the absence of known AF/atrial flutter at baseline. The primary outcome was the occurrence of new-onset AF. Our primary hypothesis was that risk for AF would simultaneously depend on both omega-3 dose (above or below 1500 mg/d) and background cardiovascular disease risk status, and that their combined impact on AF risk would be synergistic.

RESULTS

A total of 35 randomized controlled trials (37 data sets; n=114 592) were included in this meta-analysis. Only studies including patients at high-risk for cardiovascular disease who were treated with high-doses of EPA/DHA (>1500 mg/d) showed a statistically significant increase in AF risk with a pooled odds ratio (OR) of 1.43 (95% CI, 1.14-1.79) and an absolute risk difference of 0.8% (0.40%-1.1%). None of the other 3 groups showed statistically significant levels of AF risk (odds ratios, 1.07 [high risk-low dose], 1.06 [low risk-low dose], and 1.03 [low risk-high dose]).

CONCLUSIONS

This meta-analysis suggests that high-dose EPA/DHA treatment is associated with an increased risk of AF in patients at high cardiovascular disease risk, whereas low-dose EPA/DHA does not appear to increase AF risk, even in high-risk populations. Further prospective studies are needed to evaluate any potential increased risk of higher doses balanced against potential benefits.