Omega-3 fatty acids in high-risk cardiovascular patients: a meta-analysis of randomized controlled trials

Systematic review and Bayesian meta-analysis of randomized controlled trials in high-risk cardiovascular patients (mostly middle-aged to older men; post-MI, ICD recipients, diabetics, and other high-risk conditions). Trials were randomized; most were double-blind with placebo or inactive oil; some were open-label with control diet; follow-up ranged from 1 to 55 months.

Omega-3 fatty acids did not significantly reduce all-cause mortality (RR 0.88, CrI 0.64–1.03) or restenosis after PCI (RR 0.89, CrI 0.72–1.05). There remains a high probability of some benefit (mortality 0.93; restenosis 0.90). Larger, longer trials showed smaller benefits, suggesting bias may contribute to observed effects. Safety: no serious safety issues; GI side effects more frequent (RR 1.29, CrI 1.02–1.61); no clear increase in bleeding or cancer. Conclusion: omega-3 supplementation may modestly reduce mortality and restenosis, but benefits are attenuated in higher-quality and longer trials; more high-quality, standardized trials are needed to determine its role in secondary prevention of cardiovascular disease.

Heterogeneity in dosage/formulations and patient populations; incomplete adverse-event reporting; restenosis analyses often based on patients who completed follow-up angiography; imperfect blinding due to fish odor; potential publication bias not detected; lack of individual-level data limits subgroup analysis.