Recruitment of Study Participants

  • Lawrence M. Friedman
  • Curt D. Furberg
  • David L. DeMets
  • David M. Reboussin
  • Christopher B. Granger


Often the most difficult task in a clinical trial involves obtaining sufficient study participants within a reasonable time. Time is a critical factor for both scientific and logistical reasons. From a scientific viewpoint, there is an optimal window of time within which a clinical trial can and should be completed. Changes in medical practice, including introduction of new treatment options, may make the trial outdated before it is completed. Other investigators may answer the questions sooner. In terms of logistics, the longer recruitment extends beyond the initially allotted recruitment periods, the greater the pressure becomes to meet the goal. Lagging recruitment will also reduce the statistical power of the trial. Selective recruitment of a lower proportion of eligible participants may increase the non-representative nature of the sample. Costs increase, frustration and discouragement often follow. The primary reasons for recruitment failure include overly optimistic expectations, failure to start on time, inadequate planning, and insufficient effort.


Potential Participant Electronic Health Record Recruitment Effort Physician Referral Recruitment Goal 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. 1.
    America speaks, polling data reflecting the views of Americans on medical, health and scientific research. Available at Access January 21, 2015.
  2. 2.
    ECRI Health Technology Assessment Information Service. Patients’ reasons for participation in clinical trials and effect of trial participation on patient outcomes. ECRI Evidence Report. April 2002, Issue 74.Google Scholar
  3. 3.
    Wright JR, Crooks D, Ellis PM, et al. Factors that influence the recruitment of patients to phase III studies in oncology. The perspective of the clinical research assistant. Cancer 2002;95:1584–1591.CrossRefGoogle Scholar
  4. 4.
    Cox K, McGarry J. Why patients don’t take part in cancer clinical trials: an overview of the literature. Eur J Cancer Care 2003;12:114–122.CrossRefGoogle Scholar
  5. 5.
    Sharp L, Cotton SC, Alexander L, et al. on behalf of the TOMBOLA group. Reasons for participation and non-participation in a randomized controlled trial: postal questionnaire surveys of women eligible for TOMBOLA (Trial of Management of Borderline and Other Low-grade Abnormal smears). Clin Trials 2006;3:431–442.Google Scholar
  6. 6.
    Barnes K. Patients provide insight into trial participation., July 4, 2007. Available at Access January 21, 2015.
  7. 7.
    Mills EJ, Seely D, Rachlis B, et al. Barriers to participation in clinical trials of cancer: a meta-analysis and systematic review of patient-reported factors. Lancet Oncol 2006;7:141–148.CrossRefGoogle Scholar
  8. 8.
    Lovato LC, Hill K, Hertert S, et al. Recruitment for controlled clinical trials: Literature summary and annotated bibliography. Control Clin Trials 1997;18:328–357.CrossRefGoogle Scholar
  9. 9.
    McDonald AM, Knight RC, Campbell MK, et al. What influences recruitment to randomised controlled trials? A review of trials funded by two UK funding agencies. Trials 2006;7:9.Google Scholar
  10. 10.
    Caldwell PH, Hamilton S, Tan A, Craig JC. Strategies for increasing recruitment to randomised controlled trials: systematic review. PLoS Med 2010;7:e1000368.CrossRefGoogle Scholar
  11. 11.
    Hanson LC, Bull J, Wessell K, et al. Strategies to support recruitment of patients with life-limiting illness for research: the palliative care research cooperative group. J Pain Symptom Manage 2014;48:1021–1030.CrossRefGoogle Scholar
  12. 12.
    Huynh L, Johns B, Liu SH, et al. Cost-effectiveness of health research study participant recruitment strategies: a systematic review. Clin Trials 2014;11:576–583.CrossRefGoogle Scholar
  13. 13.
    Embi PJ, Jain A, Clark J, et al. Effect of a clinical trial alert system on physician participation in trial recruitment. Arch Intern Med 2005;165:2272–2277.CrossRefGoogle Scholar
  14. 14.
    Thadani SR, Weng C, Bigger JT, et al. Electronic screening improves efficiency in clinical trial recruitment. J Am Med Inform Assoc 2009;16:869–873.CrossRefGoogle Scholar
  15. 15.
    Hawkins MS, Hough LJ, Berger MA, et al. Recruitment of veterans from primary care into a physical activity randomized controlled trial: the experience of the VA-STRIDE study. Trials 2014;15:11.CrossRefGoogle Scholar
  16. 16.
    Weng C, Appelbaum P, Hripcsak G, et al. Using EHRs to integrate research with patient care: promises and challenges. J Am Med Inform Assoc 2012;19:684–687.CrossRefGoogle Scholar
  17. 17.
    Fröbert O, Lagerqvist B, Olivecrona GK, et al. Thrombus aspiration during ST-segment elevation myocardial infarction. N Engl J Med 2013;369:1587–1597.CrossRefGoogle Scholar
  18. 18.
    Kääriäinen I, Sipponen P, Siurala M. What fraction of hospital ulcer patients is eligible for prospective drug trials? Scand J Gastroenterol 1991;186:73–76.CrossRefGoogle Scholar
  19. 19.
    Sheldon T. Dutch neurologist found guilty of fraud after falsifying 438 case records. Br Med J 2002;325:734.CrossRefGoogle Scholar
  20. 20.
    Ross DB. The FDA and the case of Ketek. N Engl J Med 2007;356:1601–1604.Google Scholar
  21. 21.
    POISE Study Group. Effects of extended-release metoprolol succinate in patients undergoing non-cardiac surgery (POISE trial): a randomised controlled trial. Lancet 2008;371:1839–1847.CrossRefGoogle Scholar
  22. 22.
    Hunninghake DB. Summary conclusions. Control Clin Trials 1987;8:1S–5S.CrossRefGoogle Scholar
  23. 23.
    Kingry C, Bastien A, Booth G, et al for the ACCORD Study Group. Recruitment strategies in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) Trial. Am J Cardiol 2007;99 (Suppl):68i–79i.Google Scholar
  24. 24.
    Hulley SB, Furberg CD, Gurland B, et al. Systolic Hypertension in the Elderly Program (SHEP): antihypertensive efficacy of chlorthalidone. Am J Cardiol 1985;56:913–920.CrossRefGoogle Scholar
  25. 25.
    Cosgrove N, Borhani NO, Bailey G, et al. Mass mailing and staff experience in a total recruitment program for a clinical trial: The SHEP Experience. Control Clin Trials 1999;19:133–148.CrossRefGoogle Scholar
  26. 26.
    Bryant J, Powell J. Payment to healthcare professionals for patient recruitment to trials: a systematic review. Br Med J 2005;331:1377–1378.CrossRefGoogle Scholar
  27. 27.
    Freedman LS, Simon R, Foulkes MA, et al. Inclusion of women and minorities in clinical trials and the NIH Revitalization Act of 1993—the perspective of NIH clinical trialists. Control Clin Trials 1995;16:277–285.CrossRefGoogle Scholar
  28. 28.
    Cook ED, Moody-Thomas S, Anderson KB, et al. Minority recruitment to the Selenium and Vitamin E Cancer Prevention Trial (SELECT). Clin Trials 2005;2:436–442.CrossRefGoogle Scholar
  29. 29.
    Glickman SW, McHutchison JG, Peterson ED, et al. Ethical and scientific implications of the globalization of clinical research. N Engl J Med 2009;360:816–823.CrossRefGoogle Scholar
  30. 30.
    Shibata M, Flather M, de Arenaza DP, et al. Potential impact of socioeconomic differences on clinical outcomes in international clinical trials. Am Heart J 2001;141:1019–1024.CrossRefGoogle Scholar
  31. 31.
    Orlandini A, Diaz R, Wojdyla D, et al. Outcomes of patients in clinical trials with ST-segment elevation myocardial infarction among countries with different gross national incomes. Eur Heart J 2006;27:527–533.CrossRefGoogle Scholar
  32. 32.
    O’Shea JC, Califf RM. International differences in cardiovascular clinical trials. Am Heart J 2001;141:866–874.CrossRefGoogle Scholar
  33. 33.
    O'Connor CM, Fiuzat M, Swedberg K, et al. Influence of global region on outcomes in heart failure β-blocker trials. J Am Coll Cardiol 2011;58:915–922.CrossRefGoogle Scholar
  34. 34.
    Mahaffey KW, Wojdyla DM, Carroll K, et al. Ticagrelor compared with clopidogrel by geographic region in the Platelet Inhibition and Patient Outcomes (PLATO) trial. Circulation 2011;124:544–554.CrossRefGoogle Scholar
  35. 35.
    Vickers A, Goyal N, Harland R, Rees R. Do certain countries produce only positive results? A systematic review of controlled trials. Control Clin Trials 1998;19:159–166.CrossRefGoogle Scholar
  36. 36.
    Ni Y, Kennebeck S, Dexheimer JW, et al. Automated clinical trial eligibility prescreening: increasing the efficiency of patient identification for clinical trials in the emergency department. J Am Med Inform Assoc 2014; epub ahead of print: doi:  10.1136/amiajnl-2014-002887.
  37. 37.
    Köpcke F, Prokosch HU. Employing computers for the recruitment into clinical trials: a comprehensive systematic review. J Med Internet Res 2014;16:e161.CrossRefGoogle Scholar
  38. 38.
    Durkin DA, Kjelsberg MO, Buist AS, et al. Recruitment of participants in the Lung Health Study, I: description of methods. Control Clin Trials 1993;14:20S–37S.CrossRefGoogle Scholar
  39. 39.
    Daly M, Seay J, Balshem A, et al. Feasibility of a telephone survey to recruit health maintenance organization members into a tamoxifen chemoprevention trial. Cancer Epidemiol Biomarkers Prev 1992;1:413–416.Google Scholar
  40. 40.
    Fields WS, Lemak NA Frankowski RF, et al. Controlled trial of aspirin in cerebral ischemia. Stroke 1977;8:301–314.CrossRefGoogle Scholar
  41. 41.
    The Coronary Drug Project Research Group. The Coronary Drug Project: design, methods, and baseline results. Circulation 1973;47:I-1-I-50.Google Scholar
  42. 42.
    The Coronary Drug Project Research Group. Clofibrate and niacin in coronary heart disease. JAMA 1975;231:360–381.CrossRefGoogle Scholar
  43. 43.
    Sackett DL. A compliance practicum for the busy practitioner. In Haynes RB, Taylor DW, Sackett DL (eds.). Compliance in Health Care. Baltimore: Johns Hopkins University Press, 1979.Google Scholar
  44. 44.
    The PEACE Trial Investigators. Angiotensin-converting-enzyme inhibition in stable coronary artery disease. N Engl J Med 2004;351:2058–2068.Google Scholar

Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  • Lawrence M. Friedman
    • 1
  • Curt D. Furberg
    • 2
  • David L. DeMets
    • 3
  • David M. Reboussin
    • 4
  • Christopher B. Granger
    • 5
  1. 1.North BethesdaUSA
  2. 2.Division of Public Health SciencesWake Forest School of MedicineWinston-SalemUSA
  3. 3.Department Biostatistics and Medical InformaticsUniversity of WisconsinMadisonUSA
  4. 4.Department of BiostatisticsWake Forest School of MedicineWinston-SalemUSA
  5. 5.Department of MedicineDuke UniversityDurhamUSA

Personalised recommendations