Informed consent for clinical trials: in search of the “best” method
Introduction
“Informed consent” is perhaps the most controversial issue in the ethics of medical research today. Although biomedical research has a history dating back to Aristotle, the idea of informed consent only surfaced in the early part of the nineteenth century and finally supplanted the paternalistic view set out in the Hippocratic Oath. Informed consent is based on the notion that a person of competent mind has the right to determine what is done to him/her and the right to determine what is not done. The request for informed consent thus serves to respect a patient's autonomy. Gross violations of this principle led to its explicit formulation in the Nuremberg Code (1949) and, more expansively, in the Declaration of Helsinki (1964). These guidelines both stress that informed consent should be voluntary, not only technically but also in spirit, and that adequate disclosure of information is crucial. Adequate information typically consists of (1) details about the procedures in question, (2) purpose of the research, (3) (expected) benefits of treatment, (4) (expected) side-effects, (5) (available) alternatives and (6) right to withdraw. Clinical trials have become one of the most widespread methods of clinical research, making them the cornerstone of evidence-based practice. The method by which potential participants are informed of their options is therefore a matter of considerable personal and public interest. We have conducted a systematic review of the empirical literature which has examined the effect of different methods of obtaining “informed consent” on recruitment rates, knowledge, attitudes and anxiety.
Section snippets
Materials and methods
We first carried out a systematic search of all literature relating to the ethics of clinical trials. We used five different methods to ascertain the relevant articles namely, an electronic literature survey (conducted on the three databases, Medline, Psychlit and BIDS1 science and social science citation indices), hand searches, personal
Studies under review
There were fourteen studies providing data on different methods of obtaining informed consent, of which all except three (McLean, 1980; Dal-Re, 1991; Levene et al., 1996) used randomised controlled trial designs i.e. they were trials of methods to get consent for trials. In terms of outcome, eleven studies examined recruitment rates to the clinical trial in question, eight studies examined understanding, and five studies looked at psychological well-being (four studies examined all three
Methodological issues
Results from hypothetical scenarios may not easily be extrapolated to the “real life” situation (King, 1986). Indeed, patients faced with difficult decisions, in reality, may be more concerned to ensure that they understand the issues, or they may make different trade-offs. Data accrued from studies based on real trials are thus more useful.
Several different instruments were used to measure psychological well-being and one administered a formal psychometric scale, while the others relied on
Conclusion
The moral imperative of informed consent is an ideal whereby patients should be given full details of the trial procedure so that a person can determine what is or is not done to him/her. In theory, if autonomy is the foundation of informed consent, a patient should be asked whether or not they wish any information upon which to base a decision, and then, given an expressed desire for information, the patient should make a considered decision about trial entry. Practice, as ever, falls short of
Acknowledgements
This study was supported by the methodology section of the National Health Technology Assessment programme. We would like to thank Mr Martin Gill, Dr Chris Hyde and Ms Jennifer Jackson for their helpful comments.
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