Expectations of benefit in early-phase clinical trials: implications for assessing the adequacy of informed consent

Abstract

Background: Participants in early-phase clinical trials have reported high expectations of benefit from their participation. There is concern that participants misunderstand the trials to which they have consented, which is based on assumptions about what patients mean when responding to questions about likelihood of benefit.

Methods: Participants were 27 women and 18 men in early-phase oncology trials at 2 academic medical centers in the United States. To determine whether expectations of benefit differ depending on how patients are queried, the authors randomly assigned participants to 1 of 3 interviews corresponding to 3 questions about likelihood of benefit: frequency type, belief type, and vague. In semistructured interviews, participants were queried about how they understood and answered the question. Participants then answered and discussed 1 of the other questions.

Results: Expectations of benefit in response to the belief-type question were significantly greater than expectations in response to the frequency-type and vague questions (P=0:02). The most common justifications involved positive attitude (n=27 [60%]) and references to physical health (n=23 [51%]). References to positive attitude were most common among participants with higher (> 70%) expectations (n = 11 [85%]) and least common among those with lower ( < 50%) expectations (n = 3 [27%]).

Conclusions: The wording of questions about likelihood of benefit shapes the expectations that patients express. Patients who express high expectations may not do so to communicate understanding but rather to register optimism. Ongoing research will clarify the meaning of high expectations and examine methods for assessing understanding.

Figure 1. Expectations of Benefit by Question Type

The figure shows the distribution of responses to the target questions regarding likelihood of benefit (medians, interquartile ranges, and the minimum and maximum values), based on the first question given. Two participants did not answer the first target question. The responses differed significantly depending on the question type (Kruskal-Wallis chi-square [2 df] = 7.5; P = .02). Responses to the belief-type question were significantly greater than responses to the frequency-type question (P = .02) and the vague question (P = .02). Responses to the frequency-type and vague questions did not differ significantly from each other (P = .92).