Obesity clinical trials experience significant challenges in Recruitment and retention, facing high attrition rates coupled with low trial success rates. Obesity clinical research on weight-management interventions includes in-person programs with counselors and facilitated group sessions, surgical techniques under the umbrella of bariatric surgery, the use of social media to change food behaviors, self-guided lifestyle interventions, self-monitoring using digital therapeutics, and injectable therapies like Mounjaro. Researchers have also explored the efficacy of mobile-delivered weight loss intervention for parents on dietary changes in both parent and child.

This article will cover the challenges and factors influencing recruitment and retention in obesity clinical trials, including issues related to participant preferences, socioeconomic factors, and attrition. It also explores various solutions and opportunities to enhance recruitment and retention, such as fully remote trial designs, e-recruitment strategies, and the use of technology in recruitment efforts.

Factors Affecting Recruitment and Retention in Obesity Clinical Trials

Recruitment and retention in obesity clinical trials are influenced by age, ethnicity, socioeconomic status, employment status, work and family commitments, overall health, and personal preferences. Participant retention can further be affected by barriers like lower initial weight loss and Study burden.

Factors affecting attrition

A study on healthy women with obesity found that study recruitment and weight loss success are not necessarily the most challenging aspects of a weight loss intervention study. In trying to understand participant retention, Bhammar et al. (2021) found that attrition was high and associated with a wide range of reasons, including study burden, work commitments, facility location, family interactions, and behavioral issues. To address these issues and maximize retention, the authors suggest supportive efforts during the consenting process and early phases of the trial through enhanced investigator-participant interactions.

Participant preferences

A Study Within A Trial (SWAT) conducted by Killeen et al. (2022) sought to improve recruitment and engagement of women with obesity by studying their preferences. The study found that women of reproductive age value research methods aligned with their lifestyles, the opportunity to learn about research and themselves, and the opportunity to help advance women’s health. According to participants, being healthy goes beyond traditional physical and functional assessments to include emotional well-being and balance. The study concluded that clinical trials should be designed considering well-being, the interconnectedness of health, and research activities that help engage the target group.

Socioeconomic factors

Weight management interventions designed for men have become more prevalent; however, a systematic review by McDonald et al. (2022) found that there is still a need to give more consideration to socioeconomic factors in such trials.

Recruitment and Retention Solutions and Opportunities

Participant recruitment and retention can be improved through various solutions, including a fully remote trial design, e-recruitment strategies, multi-level approaches for medically underserved communities, multicomponent strategies, e.g., home environment changes or dietician-assistant behavior change plans, and self-monitoring tech with feedback.

1. Fully remote trial design

The fully remote, randomized pilot study of a digital weight loss intervention among racial and ethnic minority adults by Patel et al. (2022) had high retention and engagement.

Patel et al. (2022) found that an orientation video to increase research literacy, trust, and awareness of time commitment and study activities helped patients decide whether to participate. The study also revealed that the fully remote trial design facilitated more rapid recruitment compared with studies with in-person procedures.

In a recent weight loss maintenance study that had to switch from in-person to fully remote during the COVID-19 pandemic, Leahey et al. (2022) found higher treatment attendance after switching and high participant retention.

2. EMR messaging and web-based recruitment

A recent study by Horst et al. (2023) aimed to identify successful recruitment strategies for adolescent and emerging adults in weight loss intervention trials, as recruitment for this population is particularly challenging. Over 100,000 adolescents and emerging adults were contacted using at least one of four recruitment methods: clinic, web-based, post, and electronic medical record (EMR) messaging. Horst et al. (2023) found that EMR messaging and web-based recruitment were the most successful and cost-effective recruitment strategies; however, they were less successful in ensuring participant diversity. The other strategies, namely clinic recruitment and postal mailings, enrolled a larger proportion of underrepresented populations.

3. Online posting and mobile app use

In a study of women of reproductive age with obesity, Simon et al. (2020) evaluated four methods of recruitment: flyers posted in relevant clinics, ads in newspapers, and e-recruitment strategies of posting online and using a mobile app. Most participants (98%) were recruited using e-recruitment strategies. Simon et al. (2020) concluded that e-recruitment strategies show promise for preconception weight-loss and lifestyle modification programs.

4. Social media

A systematic review by Ellington et al. (2022) on the effectiveness of social media in recruiting healthy participants for studies related to nutrition, physical activity, and obesity found that for online study procedures, approximately half the studies reported that social media was more effective. However, only 21.2% of those interacting with ads on social media were eventually enrolled. The study anticipates that with the growth in the use of social media, future systematic reviews may yield different results.

5. Reaching underrepresented groups

Pérez-Muñoz et al. (2022) studied the effectiveness and cost-effectiveness of local and national recruitment strategies for Fit & Quit, a smoking cessation and weight management RCT. Most effective were local postcards, local radio ads, word-of-mouth referrals, and national internet ads, collectively contributing to 71.8% of the randomized sample. Radio ads were the best recruitment strategy for Black participants, while e-recruitment strategies were the most effective for non-urban participants. Electronic media techniques were cost-effective ($430.97 per participant) and more cost-effective than traditional media ($931.43 per participant). However, traditional media methods accounted for more recruited and randomized participants.

To improve the engagement (and associated retention) of underrepresented groups by occupation, namely men who work in skilled and skilled trades and labor occupations, Crane et al. (2022) sought to better understand their preferences for weight loss programs. The results indicated that this group preferred programs that encourage smaller dietary changes, are delivered online, and do not require competition. Another study focused on the same demographic found a preference for programs that match their lifestyle and information that is accurate and trustworthy.

6. Multi-level approaches for medically underserved communities

On childhood obesity, Brock et al. (2021) highlighted a gap in research on effective recruitment and engagement strategies for rural communities. In their study of family-based childhood obesity treatment interventions, the researchers demonstrated the need for multi-leveled approaches that provide infrastructure support and strategy to improve stakeholder capacity for recruiting and engaging participants.

They recommended performing readiness assessments, conducting awareness campaigns, identifying barriers to participant engagement, and piloting and evaluating recruitment and engagement strategies.

7. Targeted effective recruitment

In a study on the challenges in recruiting men for weight loss intervention trials, Rounds & Harvey (2019) found that a newspaper ad was the most effective recruitment technique. They achieved high retention throughout and surmised that a targeted, effective recruitment strategy, rather than interest in weight loss, may be more important for the participation of overweight and obese men.

Conclusion

Recruitment and retention in obesity clinical trials are influenced by multiple factors, including barriers, opportunities, and participant preferences, which must be considered in clinical trial design. Ultimately, these factors are unique to the target group, may shift over time, and must be better understood to drive effective recruitment and retention solutions. Across various interventions and target populations, technology-driven recruitment and engagement have been found to be effective strategies.

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