Influences on clinical trial participation: Enhancing recruitment through a gender lens - A scoping review.

Background: Suboptimal clinical trial recruitment contributes to research waste. Evidence suggests there may be gender-based differences in willingness to participate in clinical research. Identifying gender-based differences impacting the willingness of trial participation may assist trial recruitment. Objectives: To examine factors that influence the willingness of men and women to participate in clinical trials and to identify modifiable factors that may be targeted to optimise trial participation. Material and methods: Electronic databases were searched with key words relating to 'gender', 'willingness to participate' and 'trial'. Included studies were English language and reported gender-based differences in willingness to participate in clinical trials, or factors that influence a single gender to participate in clinical trials. Studies were excluded if they described the demographic factors of trial participants or if the majority of participants were pregnant. Extracted data were coded, categorized, analysed thematically and interpreted using Arksey and O'Malley's framework. Results: Sixty-three studies were included. Two main themes were identified: trial characteristics and participant characteristics. A number of gender-based differences moderating willingness to participate were observed although only one, 'concern for self' was found to influence actual trial participation rates between genders. Conclusion: The relationship between factors influencing willingness to participate in clinical trials is complex. The influence of gender on willingness to participate, while important, may be moderated by other factors including socioeconomic status, ethnicity and health condition. Exploring factors that influence willingness to participate specific to a study cohort likely offers the most promise to optimise trial recruitment of that cohort.