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

BACKGROUND: 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. OBJECTIVES: 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. RESEARCH DESIGN: 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. SUBJECTS: Adults recruited from an online panel constructed from a probability sample of US-based postal addresses. MEASURES: 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). RESULTS: 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. CONCLUSIONS: 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. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11606-021-07087-8.