[aladoc99]

It seems as though people are getting the idea that this was a randomized trial, where people were assigned to receive units of blood from various types of donors. However, it was a retrospective case-control study, where records from everyday clinical practice were analyzed after the fact to look for patterns or, as in this case, try to answer questions. Did people who had received units of PRBCs from various types of donors fare any differently? I tend to view this kind of study as valuable for hypothesis generation, but not for solid conclusions, because it's impossible to control for every possible confounding factor. So the notion of ethics committees being concerned about patient's mortality doesn't apply here. All patients in the study have already either survived the study period or not. Same for safeguards, monitoring, and early termination.