Potential confounders. To minimize the untoward effect of differences in CV risk anti-platelet, lipid-lowering, and antidiabetic agents, when needed, will be given to all patients, and maintained at the same dosage achieved at the end of the run-in period throughout the study. The possible unbalanced distribution of confounders between treatment arms will be handled by calculating the propensity score (8, 9) and entering it in the Cox regression analysis.