UMMS Affiliation

Department of Family Medicine and Community Health

Publication Date


Document Type



Clinical Trials | Public Health | Quality Improvement | Race and Ethnicity | Translational Medical Research


While extensive literature exists on barriers and strategies to increase minority participation in clinical trials, progress is limited. Few strategies were evaluated in randomized trials. We studied the impact of RECRUIT, a trust-based, cluster randomized minority recruitment trial layered on top of four traditional NIH-funded parent trials (BMT CTN, CABANA, PACES, STEADY-PD III; fifty specialty sites). RECRUIT was conducted from July 2013 through April 2017. Intervention sites implemented trust-based approaches customized to individual sites, promoting relationships between physician-investigators and minority-serving physicians and their minority patients. Control sites implemented only parent trials' recruitment procedures. Adjusting for within-site clustering, we detected no overall intervention effect, odds ratio 1.3 (95% confidence limits 0.7,2.4). Heterogeneity among parent trials may have obscured the effect. Of the four parent trials, three enrolled more minorities in intervention versus control sites. CABANA odds ratio = 4.2 (adjusted 95%CL 1.5,11.3). PACES intervention sites enrolled 63% (10/16) minorities; control sites enrolled one participant in total, a minority, yielding an incalculable odds ratio. STEADY-PD III odds ratio = 2.2 (adjusted 95%CL 0.6,8.5). BMT CTN odds ratio < 1, 0.8 (adjusted 95%CL 0.4,1.8). In conclusion, RECRUIT findings suggest the unique trust-based intervention increased minority recruitment to intervention trials in (3/4) of studied trials. Physician-investigators' participation was critical to recruitment success. Lack of commitment to minority recruitment remained a barrier for some physician-investigators, especially in control sites. We recommend prospective physician investigators commit to minority recruitment activities prior to selection as site investigators and trial funding include some compensation for minority recruitment efforts.TRIAL REGISTRATION ClinicalTrials.govNCT01911208.


Cluster-randomized trial, Continuous quality improvement, Intervention mapping, Minority recruitment, Specialty clinics

Rights and Permissions

© 2021 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (

DOI of Published Version



Tilley BC, Mainous AG 3rd, Amorrortu RP, McKee MD, Smith DW, Li R, DeSantis SM, Vernon SW, Koch G, Ford ME, Diaz V, Alvidrez J; additional RECRUIT Trial Center and Parent Trials' investigators. Using increased trust in medical researchers to increase minority recruitment: The RECRUIT cluster randomized clinical trial. Contemp Clin Trials. 2021 Oct;109:106519. doi: 10.1016/j.cct.2021.106519. Epub 2021 Jul 30. PMID: 34333138; PMCID: PMC8665835. Link to article on publisher's site

Journal/Book/Conference Title

Contemporary clinical trials

Related Resources

Link to Article in PubMed

PubMed ID


Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.