Recruitment in randomized clinical trials: The MeMeMe experience

Area of Science:

• Clinical Trial Recruitment
• Preventive Medicine
• Metabolic Disease Research

Background:

• Clinical trial recruitment is critical for study success.
• The MeMeMe trial investigates a Mediterranean diet with or without metformin for preventing age-related chronic diseases.
• Understanding recruitment and withdrawal patterns is key to optimizing trial design.

Purpose of the Study:

• To report on the recruitment experience of the MeMeMe trial.
• To analyze the effectiveness of "active" versus "passive" recruitment strategies.
• To identify factors influencing participant withdrawal from the clinical trial.

Main Methods:

• Statistical analysis of 2035 volunteers, categorizing recruitment as "active" or "passive".
• Logistic regression models were used to assess withdrawal risk factors.
• Factors analyzed included recruitment method, sex, age, BMI, and weight change.

Main Results:

• "Passive" recruitment (67.6%) was more common than "active" recruitment (32.4%).
• Withdrawal rates were similar between active (19.5%) and passive (22.0%) recruitment.
• Higher withdrawal risk was associated with being female, older age, and higher baseline BMI. Weight loss in the first year significantly reduced withdrawal risk.

Conclusions:

• "Passive" recruitment proved more effective for advancing enrollment in the MeMeMe trial.
• Despite higher effectiveness, the advantages of "passive" recruitment were marginal.
• Participant characteristics (sex, age, BMI) and adherence (weight change) significantly impact trial retention.