The study is powered to find an absolute mortality reduction (ARR) of ~6-7%. Based on the control arm mortality rate, we originally estimated a sample size of 1950. During the trial, the ProCESS Coordinating Center monitored the overall mortality rate, and appreciated that it was markedly lower than originally projected. Therefore, following a series of new calculations, in February 2013, the trial was re-sized to 1350 patients (450 patients per arm). The new size preserves the same power to find the same ARR. The resizing was fully blinded and approved by the NIH.