Accuracy of Event Rate and Effect Size Estimation in Major Cardiovascular Trials: A Systematic Review.

Importance: For the design of a randomized clinical trial (RCT), estimation of the expected event rate and effect size of an intervention is needed to calculate the sample size. Overestimation may lead to an underpowered trial.

Objective: To evaluate the accuracy of published estimates of event rate and effect size in contemporary cardiovascular RCTs.