[Information provided in writing for "informed consent" in clinical trials]

The Helsinki Declaration contains recommendations guiding physicians who conduct clinical trials. One is that the requirement for informed consent is essential for approval of a trial. An important component of the informed consent doctrine is that all data required for the participant's decision must be provided. We analyze data of a therapeutic trial, and define 12 data components outlined in, or directly derived from the Helsinki Declaration. 61 instances of informed consent for therapeutic clinical trials from various fields of medicine, from 1994 to 1997, were analyzed. In each the presence of the 12 components was evaluated. The data demonstrated that there were only 5 components cited in most cases of informed consent: trial objectives, methods, treatment plan, risks, and the option of withdrawing. Benefit to the participant was mentioned in half the cases, while only limited information was provided about other components such as life-threatening and unpredictable risks, and alternative treatment. Examples of informed consent from 1997 showed statistical improvement since 1994 in the data concerning trial objectives, methods, risks and alternative therapy. Informed consent documents of international multicenter trials compared with local trials showed statistical improvement in the data components of the trial objectives, methods, and risks, including those of potentially life-threatening and unpredictable risks, and alternative therapy. Analysis of informed consent showed that not all components required for a comprehensive decision regarding participation in a clinical trial are included. These data emphasize the need to design a structured informed consent protocol in which all the required data components are specifically outlined for potential participants.