Why blind those conducting interim reviews

♦ knowledge of treatment may affect judgement.

While these are the reasons generally given in favour of blinding, there are strong arguments against. If an independent committee reviewing interim data is blinded to the treatment allocation, then it follows that they are expected to consider the trial in isolation, ignoring any previous trials. It is now widely accepted that before a treatment can be adopted as standard, it is necessary to conduct a systematic review of all the available evidence (see Chapter 11). If a DMEC are to make an informed and clinically relevant decision about the continuation or otherwise of a trial, then they should also be aware of how the present trial fits in with existing data. An example of a trial in which the DMEC's decisions at each stage were always informed by consideration of how the trial would impact on existing data and opinions is given in [29].

0 0

Post a comment