Mediterranean diets and metabolic syndrome status in the PREDIMED randomized trial

In November 2014, CMAJ published “Mediterranean diets and metabolic syndrome status in the PREDIMED randomized trial,”1 a secondary analysis of the PREDIMED study published in the New England Journal of Medicine in 2013 and subsequently retracted and republished June 13, 2018.2 The authors have contacted CMAJ to inform us about some irregularities in the randomization process in several study sites and have supplied us with a preliminary reanalysis addressing the randomization issues. We are issuing this expression of concern, pending completion of our review of the reanalysis. We appreciate the proactive actions of the PREDIMED Study Investigators in this matter.