Sample size re-estimation in an on-going NIH-sponsored clinical trial: the secondary prevention of small subcortical strokes experience.

ABSTRACT:

Background and purpose

When planning clinical trials, decisions regarding sample size are often based on educated guesses of parameters, which may in fact prove to be over- or under-estimates. For example, after initiation of the SPS3 study, published data indicated that the recurrent stroke rates might be lower than initially planned for the study. Failure to account for this could result in an under-powered study. Thus, we performed a sample size re-estimation, and describe the experience herein.

Methods

We evaluated different scenarios based on a re-estimated overall event rate, including increasing the sample size and increasing the follow-up time, to determine their impact on both type I error and the power to detect the initially planned treatment difference.

Result

SUBMITTER: McClure LA 

PROVIDER: S-EPMC3408857 | biostudies-literature | 2012 Sep

REPOSITORIES: biostudies-literature