Effects of simulated sample sizes on the mortality effect estimates in three randomized intensive care unit trials.

In this post hoc study of three international RCTs within intensive care, we found that the simulated interim mortality effect estimates showed considerable fluctuations until at least 20%-30% of the sample size was included, but remained instable until the final sample sizes had been included. Thus, this study illustrates the necessity for cautious interpretations of prematurely stopped trials.