Can metaphors in patient information materials improve comprehension and attitudes regarding innovative treatment? The case of personalized immunotherapy for sepsis

Objectives: Effective communication is essential for patients and their relatives to comprehend and accept novel treatments, such as personalized immunotherapy for sepsis in the ICU. However, communication in the ICU is challenging. Written information materials can supplement conversations with healthcare providers, enabling patients and their relatives to consult information later. Metaphors are often employed to explain complex medical concepts. The aim of this study was to investigate whether and how the use and choice of metaphors in patient information materials improves people's comprehension and attitudes regarding personalized immunotherapy for sepsis. Methods: We performed a single-factor between-subjects experiment with four different texts explaining personalized immunotherapy for sepsis: one control and three metaphorical texts using the source domains of WAR, JOURNEY and NATURAL PHENOMENON. Participants (N = 1098) were native English U.K. citizens recruited through Prolific. They read a scenario about their relative being admitted to the ICU with sepsis, followed by one of the four texts. Participants then completed questions assessing comprehension and attitudes towards the treatment. Results: Scores on all variables were generally high, but no significant differences were found between the metaphor and non-metaphor groups, nor between the source domains. Exploratory analyses suggested differences in effectiveness of metaphorical source domains based on education level and topic familiarity. Conclusion: Participants demonstrated a good comprehension and a positive attitude regarding personalized immunotherapy for sepsis, regardless of metaphor use. For specific audiences, tailoring metaphors might enhance comprehension and attitudes. Practice implications: This study informs the use of metaphors in patient information materials for personalized immunotherapy for sepsis. While the findings suggest that metaphors do not improve comprehension or attitudes, they also do not backfire. Exploratory findings suggest it is important to consider individual differences in how people prefer to receive and process information.