Patients' Reactions to Letters Communicating Collateral Findings of Pragmatic Clinical Trials: a National Web-Based...

Collateral findings in pragmatic clinical trials are findings that may have implications for patients' health but were not generated to address a trial's primary research questions. It is uncertain how best to communicate these collateral findings to patients.

To determine how reactions to a letter communicating collateral findings relate to who signed the letter, the type of finding, or whether the letter specified that the finding arose from a pragmatic clinical trial.

Web-based survey experiment using a between-subjects design in which respondents were randomly assigned within education strata to view and respond to 1 of 16 hypothetical scenarios.

Adults recruited from an online panel constructed from a probability sample of US-based postal addresses.

The primary outcomes were the action the respondent would take next (i.e., contact a doctor immediately or something else) and the respondent's emotional reactions (i.e., all positive, all negative, mixed, or none).

A total of 4080 respondents had analyzable data. Although some effects were statistically significant (P < .05), none exceeded a prespecified threshold for policy relevance (15 or more percentage points). Ratings of letter clarity and level of understanding were lower for letters that included a description of the clinical trial.

Signatory and level of detail about collateral findings did not substantially affect people's intentions to take the recommended action of contacting their doctor. Deciding whether to include a description of the pragmatic clinical trial requires a trade-off between transparency and more difficulty understanding the contents of the letter.