Mediterranean diet adherence linked to reduced cardiovascular events and mortality in established CVD

BACKGROUND: Cardiovascular diseases (CVD) are the leading cause of mortality worldwide, with secondary prevention a public health priority. Diet is a modifiable risk factor, and adherence to the Mediterranean diet (MD) has shown benefits in primary prevention. However, its role in patients already affected by CVD remains uncertain. This systematic review and meta-analysis aimed to evaluate the association between adherence to MD and recurrent cardiovascular events, mortality, and intermediate health outcomes in individuals with established CVD. METHODS: This review was conducted in accordance with PRISMA 2020 and MOOSE guidelines. A comprehensive search of PubMed/MEDLINE, Scopus, Embase, and Cochrane Library was performed up to February 28, 2024. The certainty of evidence was evaluated with the NUTRIGRADE approach. Pooled effect sizes were computed using a random-effects model and expressed as risk ratios (RR), hazard ratios, or odds ratios, as appropriate. RESULTS: Nineteen studies (4 randomized controlled trials-RCTs, 15 cohorts) involving over 91 000 participants were included. Higher adherence to MD was associated with a reduced risk of major adverse cardiovascular events in cohorts (RR 0.95, 95% CI: 0.93-0.97) and RCTs (RR 0.44, 95% CI: 0.20-0.94), and reduced mortality in cohorts (RR 0.96, 95% CI: 0.95-0.98) and RCTs (RR 0.27, 95% CI: 0.13-0.55). Effects on blood pressure and lipid profile were not significant, while effects on body composition were non-significant. Certainty of evidence ranged from low to high depending on the different outcomes. CONCLUSIONS: Higher adherence to the MD is associated with clinically meaningful reductions in recurrent cardiovascular events and mortality among CVD patients. These findings support incorporating MD-based recommendations into secondary prevention guidelines and public health strategies.