Empirical evaluation of the need for 'on-going consent' in clinical research.

Objective: Some commentators argue that informed consent for clinical research should be an on-going process, which begins, rather than ends, with participants' initial consent. Lacking, however, are empirical data on whether there is a need for 'on-going consent'.

Design: Two self-administered surveys - a baseline survey at initial consent and a follow-up survey 2-3 years later - to assess whether participants remain informed over time.

Methods: Respondents were adults with HIV disease from Argentina, Brazil and Thailand enrolled in a long-term clinical trial.

Results: Respondents overall were well informed at baseline. At follow-up, many reported being not informed about aspects of the study central to their on-going participation. With respect to the possibility of withdrawal, 38.5% of respondents at follow-up reported being 'not at all' informed. At follow-up, 71.1% wanted more information. Yet, 62.8% had not asked any questions during the entire study. Reasons for not asking questions included not having an opportunity (16.4%) and not knowing whom to ask (15.5%).

Conclusions: The standard consent process resulted in participants being well informed at enrollment. Yet, this process was not sufficient to keep them informed about aspects of the study central to their on-going participation. In addition, participants who wanted more information often did not ask for it. These findings provide empirical support for recommendations that clinical trials should consider including a process of 'on-going consent'.