Determining call-to-entry rate and recruitment barriers in clinical studies for community clinics serving low-income populations: A cohort study

Elizabeth M. Vaughan, Salim Virani, Mahmoud Al Rifai, Victor J. Cardenas,, Craig A. Johnston, Laura Porterfield, Zuleica Santiago Delgado, Susan L. Samson, Vanessa Schick, Aanand D. Naik

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Background Recruitment for clinical studies is challenging. To overcome barriers, investigators have previously established call-to-entry rates to assist in planning. However, rates specific to low-income minority populations are needed to account for additional barriers to enrolment these individuals face. Objective To obtain a call-to-entry rate in a low-income uninsured Hispanic population with chronic disease. Methods We used data from four of our randomised clinical studies to determine the call-to-entry rate for individuals (n=1075) with or at risk for type 2 diabetes: participants needed/potential participants contacted=recruitment rate (yield). Research staff contacted potential participants to enrol in a study that evaluated 6 month diabetes programmes at community clinics from 2015 to 2020. We recorded call-to-entry rates, reasons for declining the study, show rates, and attrition. Results The call-to-entry rate was 14.5%. Forty per cent of potential participants could not be contacted, and 30.6%, 19.1%, and 5.4% responded yes, no, and maybe, respectively. No show percentages were 54% for yes and 91.4% for maybe responders. The majority (61.6%) declined due to inability to attend; reasons to decline included work (43%), eligibility (18%), transportation (10%), out of town (9%), did not think they needed the programme (7%) and other/unknown (14%). Being a physician predicted inability to reach participants (adjusted OR 2.91, 95% CI 1.73 to 4.90). Attrition was 6.8%. Conclusions We described a call-to-entry rate and detailed recruitment data, including reasons to decline the study. This valuable information can assist investigators in study planning and overcoming enrolment barriers in low-income populations. Telehealth-based or strategies that limit transportation needs may increase participant involvement. Trial registration number NCT03394456.

Original languageEnglish (US)
Article numbere077819
JournalBMJ open
Issue number10
StatePublished - Oct 28 2023


  • clinical trial
  • community health workers
  • diabetes
  • low-income
  • recruitment
  • telehealth

ASJC Scopus subject areas

  • General Medicine


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