We determined that with enrollment of 900 patients (600 in the evolocumab group and 300 in the placebo group) the study would have sufficient power (>99%) to detect at least a 20% reduction in the LDL cholesterol level in the evolocumab group, as compared with the placebo group, with a common standard deviation of 20%, after accounting for treatment attenuation and assuming that 2% of the patients would not receive a study drug. All analyses included data from patients who received at least one dose of a study drug. We analyzed all primary and secondary efficacy end points on the basis of the randomized study-group assignments.