Recruiting and retaining participants in a combined behavioral and pharmacological clinical trial.

Objective: This article focuses on the practical and methodological considerations that went into recruiting and retaining participants in a complex clinical trial. It describes multiple recruitment strategies that were employed to meet stringent eligibility criteria and manage efficiently the flow of participants to fulfill recruitment goals. Both study-wide and site-specific methods that were employed to maximize retention rates are discussed. Also discussed is how the coordinating center worked together with study investigators to improve recruitment and retention.

Method: A multidimensional perspective on recruitment and retention is discussed. Details are provided on how barriers to recruitment and retention were addressed. Intervention strategies designed by the coordinating center to meet performance goals are described. Data are presented to support the utility of recruitment and retention methods. The COMBINE Study served as a case illustration for various issues addressed in the article.

Results: As a result of the combined efforts of the coordinating center and study sites, there was steady improvement in recruitment and retention rates over the course of the trial. The recruitment goal of 1,375 participants was surpassed by September 2003. Also, improvement in data completeness rates improved by 18-27 percentage points over a 3-year period, culminating in follow-up rates meeting or exceeding performance goals by 2004.

Conclusions: Various strategies and procedures designed to address recruitment and retention problems in large, complex combination pharmacotherapy and behavioral trials were effective in meeting recruitment and retention goals. The lessons learned may be of value to investigators not only involved in multisite, combination trials but in monotherapy and/or single-site studies as well.