Methodological Quality of Meta‐Analyses on the Mediterranean Diet and Cardiovascular Disease

Abstract

Several systematic reviews/meta‐analyses published within the last 10 years have examined the effects of Mediterranean style diets (MedSD) on cardiovascular disease (CVD) risk. However, these reports have not been evaluated for satisfying contemporary methodological quality standards. To assess compliance with current standards, we applied a modified version of the Assessment of Multiple Systematic Reviews (AMSTARMedSD) quality scale to systematic reviews/ meta‐analyses retrieved from electronic databases that had met our selection criteria: (1) used systematic or meta‐analytic procedures to review the literature; (2) examined MedSD trials; and (3) had MedSD interventions independently or combined with other interventions. Reviews completely satisfied from 8% to 75% of the AMSTARMedSD items (Mean=31.6%±19.6%), with those published in higher impact journals having greater quality scores. At a minimum 50% of the 20 reports did not disclose full search details or apply appropriate statistical methods to combine study findings. Only two of the reviews included participant or MedSD diet characteristics in their analyses. These data suggest that current meta‐analyses evaluating the effect of MedSD on CVD risk do not fully comply with contemporary methodological quality standards. As a result they have contributed less than ideally to our understanding of how MedSD impacts CVD risk, or how these effects may be moderated by the participant or MedSD characteristics. In order to clarify the effects of MedSD on CVD risk,future meta‐analyses need to adhere to contemporary methodological quality standards.FundingUSDA Hatch project 1000900, CONS000927