The PREDIMED Trial
Eligible participants were mostly older Caucasian women with no evidence of cardiovascular disease at enrollment, with either type II diabetes mellitus or at least three of the following major risk factors: smoking, hypertension, elevated LDL levels, low HDL levels, overweight or obesity, or a family history of premature coronary heart disease:
|BMI > 30||47%|
|FH of Heart Disease||20%|
- The Predimed trial excluded participants with a documented history of previous cardiovascular disease, including CAD, stroke or peripheral artery disease, but to my knowledge there were no pre-trial tests for asymptomatic CV disease.
- At a mean age of 67yo, it is unlikely that coronary artery disease was yet to develop in this population. It is also unclear if CVD was excluded in the study groups by any other means than a questionnaire.
- The high percentage (60%) of almost 100% all-white female non-smokers, but with multiple other risk factors for heart disease (excluding an mostly negative family history) predicts CV disease in a significance number of participants.
- It is therefore reasonable to assume that a significant number of these participants had prior asymptomatic CAD.
Only 15% were current smokers, while 60% never smoked, suggesting a difficult-to-believe patient selection, considering the high rates of European smokers (40% in Spain, where the study was performed):
Female smokers (2010 data)
Male smokers (2010 data)
The outcome, that the Mediterranean diet supplemented with extra-virgin olive oil or nuts reduced the incidence of major cardiovascular events by 30%, is therefore remarkable, even if the sudy was conducted with a highly selective population.
Actual Results of the Predimed trial:
Kaplan–Meier Estimates of the Incidence of Outcome Events in the Total Study Population.
Panel A shows the incidence of the primary end point (a composite of acute myocardial infarction, stroke, and death from cardiovascular causes), and Panel B shows total mortality. Hazard ratios were stratified according to center (Cox model with robust variance estimators). CI denotes confidence interval, EVOO extra-virgin olive oil, and Med Mediterranean.
Results of Subgroup Analyses.
Shown are adjusted hazard ratios for the primary end point within specific subgroups. Squares denote hazard ratios; horizontal lines represent 95% confidence intervals. Hazard ratios indicate the relative risk in both intervention groups merged together (vs. the control group) within each stratum. Hazard ratios were stratified according to recruiting center and were adjusted for sex, age (continuous variable), family history of premature coronary heart disease (CHD) (yes or no), smoking (never smoked, former smoker, or current smoker), body-mass index (BMI) (continuous variable), waist-to-height ratio (continuous variable), hypertension at baseline (yes or no), dyslipidemia at baseline (yes or no), and diabetes at baseline (yes or no). Scores for adherence to the Mediterranean diet range from 0 to 14, with higher scores indicating greater adherence.