Predicting the placebo response in a clinical trial based on pre-trial data

Published trial data have rarely allowed to identify factors contributing to the placebo response (PR) size, and raw data from clinical trial records have usually been unaccessible for this purpose. Methods: We re-analysed the trial data from a recent functional dyspepsia (FD) trial with Iberogast (R) (Am J Gastroenterol 102;2007:1268–75) for factors determining predictors of PR and placebo non-response (PnR) in the placebo arm (n=157) of the study. Variables tested were the total gastrointestinal symptom score (GIS) at run-in, GIS change during run-in, type of FD symptoms, duration of illness, age, gender, body…