Question special

Given the combination of three large trials into this meta-analysis, the final data set was drawn from a wide variety of locations (138 hospitals in 7 countries). With the importance of "usual care" in the protocol of each trial, I wondered if the clinical practices that made up usual care differed significantly amongst the various clinical sites for the trial. While overall there was no overall difference in mortality between the intervention and control groups, one could imagine a scenario where EGDT was superior to usual care at one site and inferior to usual care at another. My questions are... How was usual care assessed? Were there any features of usual care that varied significantly amongst clinical sites, or were clinical practice patterns found to be fairly standardized? If differences were present, was there any evidence that these different practice patterns contributed to the variance in final outcomes?