Commentary: Problems with randomised consent

摘要

The study by Steiner and colleagues was undertaken using the randomised consent or Zelen's method of trial design. This method involves asking trial participants' consent to receive the treatment they have been randomised to, not to randomisation itself. The ethical issues of consent have been extensively debated in the BMJ, and I do not propose to revisit these here. Zelen's method is a scientifically useful way of evaluating some interventions, such as population screening programmes, and is extensively used in cluster trials. However, this study is a rare example of an individually randomised non-screening trial using the method. There are two versions of the design: single and double consent. In this study the authors seem to have used the single consent method, whereby only those patients allocated to the nurse-led unit were asked for consent to be transferred to the unit.