The extent of written trial information: preferences among potential and actual trial subjects.

Aim: To investigate the preferred extent of written information in clinical trials among potential and actual trial participants.
Materials and Methods: Questionnaire survey among citizens of Copenhagen County (PUB, N=508), patients attending an out-patient clinic (OPC, N=200), and finally among participants in two clinical trials (ROC, N=32; MRCRUC, N=47--see Abbreviations). Questions concerned attitudes to and preferences towards a relatively short ("short form") and a more detailed information form ("long form") about a hypothetical, but realistic trial.
Results: Approximately 1/8 of the respondents in PUB were satisfied with the "short form", whereas this was the case for approximately 1/6 of outpatients and 1/5 of actual trial participants. Regarding the "long form" approximately three quarters of respondents in all groups were satisfied. Outpatients as a whole were satisfied to a larger extent that respondents from the PUB trial concerning the "short form" (p=0.04). The "long form" was preferred by a little less than 4/5 of respondents in all groups.
Conclusion: Written information to trial subjects should be detailed, as a majority of both potential and actual research participants prefers this, given the choice between two information forms of different extent on the same trial.