Mediterranean Diet and Mortality in People with Cardiovascular Disease: A Meta-Analysis of Prospective Cohort Studies

The association of the Mediterranean diet (MD) with mortality among people with a history of cardiovascular disease (CVD) has not been systematically examined. Hereby, our objective was to investigate the association of MD with all-cause and cardiovascular mortality in people with a history of CVD. We searched five electronic databases including Embase, PubMed, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials to screen eligible studies published before 31 August 2020. A random-effect model was used to examine the association of a 2-unit increment in MD score with the risk of all-cause and cardiovascular mortality. We conducted sensitivity and subgroup analyses and examined potential publication bias by Egger's and Begg's tests. Seven cohort studies (eight datasets) with a total of 37,879 participants who had a history of CVD were eligible for the main analysis. The pooled hazard ratios were 0.85 (95% CIs: 0.78-0.93; n = 8) for all-cause mortality and 0.91 (95% CIs; 0.82-1.01; n = 4) for cardiovascular mortality for each 2-unit increment in a score of adherence to MD. Subgroup analyses for all-cause mortality showed that the association appeared relatively stronger in Mediterranean areas (HR = 0.76 [0.69-0.83]) than non-Mediterranean areas (HR = 0.95 [0.93-0.98]) and in studies with a shorter duration (HR = 0.75 [0.66-0.84] for <7 years vs. HR = 0.94 [0.91-0.98] for ≥7 years). No evidence of publication bias was observed. The present meta-analysis of prospective cohort studies provided evidence that adherence to MD improved survival in people with a history of CVD.