Formulation-Specific Cardiovascular Outcomes with High-Dose Eicosapentaenoic Acid: A Systematic Review and Meta-analysis

Abstract

Background/Objective

Residual cardiovascular risk persists despite intensive statin therapy in patients with established atherosclerotic cardiovascular disease (CVD). Omega-3 fatty acids, particularly high-dose eicosapentaenoic acid (EPA), have been proposed as adjunctive therapy, yet trial results conflict, likely due to formulation differences. We conducted a formulation-focused meta-analysis to determine whether high-dose EPA-dominant supplementation reduces cardiovascular events and to quantify the impact of mixed EPA/docosahexaenoic acid (DHA) regimens on efficacy.

Methods

Following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 guidelines, we searched MEDLINE, Embase, CENTRAL, and trial registries through May 2025 for randomized controlled trials, including placebo-controlled and open-label designs, of high-dose EPA-dominant omega-3 (≥ 1.8 g/day; ≥ 50% EPA) in adults with established CVD or other high-risk settings. Six trials (n = 42,738; 31–85% male) were eligible. Random-effects models generated pooled risk ratios (RRs), with I² assessing heterogeneity; sensitivity analyses excluded mixed EPA/DHA formulations. Imaging surrogate outcomes were summarized narratively when study modalities were not directly comparable.

Results

EPA-based therapy significantly reduced hospitalizations for unstable angina (RR 0.75, 95% CI 0.66–0.87; I² = 0%). Overall effects on recurrent myocardial infarction and revascularization were not statistically significant, but both became significant after exclusion of STRENGTH, the only mixed EPA/DHA cardiovascular outcomes trial. No significant effect was observed for ischemic stroke, cardiovascular death, or high-sensitivity C-reactive protein (hs-CRP). CHERRY and EVAPORATE both suggested attenuation of plaque progression, but these imaging studies were not pooled because intravascular ultrasound and coronary computed tomography angiography-derived measures were not directly comparable.

Conclusion

High-dose EPA-dominant therapy was associated with fewer unstable angina hospitalizations, and formulation appeared to modify clinical benefit. Among blinded, placebo-controlled, cardiovascular outcomes trials, 4 g/day icosapent ethyl is the only formulation independently associated with reduced cardiovascular events. Larger formulation-specific trials are needed to clarify the roles of purified EPA, mixed EPA/DHA regimens, and patient selection.

Registration

PROSPERO identifier number: CRD420251063069.