Efficacy of different doses of omega-3 fatty acids on cardiovascular outcomes: Rationale and design of a network meta-analysis

INTRODUCTION: The impact of omega-3 fatty acids (O3FA) supplementation on cardiovascular risk is still in debate, largely due to the heterogeneity of population enrolled and variable dose and composition of the formulations used in the previous studies. Yet, O3FA may favorably impact on cardiovascular risk by reducing major cardiovascular events (including cardiac death and ischemic events). EVIDENCE ACQUISITION: We aim to perform a comprehensive review of the topic of O3FA for cardiovascular prevention, stemming from a systematic review, to pairwise meta-analysis and network meta-analysis, limiting our inclusion only to randomized clinical trials comparing low dose (LD) (<1 g per day) O3FA and high dose (HD) (>1 g per day) O3FA versus placebo. The efficacy outcomes of interest are total death, cardiac death, sudden cardiac death, myocardial infarction, stroke, coronary revascularization, unstable angina and major vascular events. Safety outcomes of interest are bleeding, gastrointestinal disturbances and atrial fibrillation events. EVIDENCE SYNTHESIS: This meta-analysis is expected to include several important studies on cardiovascular primary and secondary prevention and detail on important cardiovascular outcomes. Furthermore, we intend to highlight safety outcomes related to O3FA supplementation. CONCLUSIONS: The present network meta-analysis results will aid physicians in the decision to prescribe O3FA in patients with or at risk of cardiovascular events. In particular, it will be able to solve controversies emerged from previous randomized clinical trials and meta-analyses regarding the benefit of different doses of O3FA supplementation in the cardiovascular prevention.