Original articlesBarriers to Participation in Randomised Controlled Trials: A Systematic Review
Introduction
The randomised controlled trial (RCT) is widely accepted as the most powerful research method for minimising bias when evaluating health technologies. However, delays and problems with recruitment of clinicians and patient participants continue to have a major impact on costs and workload of trials 1, 2, and on their subsequent value. The scale of the problem is not well documented, but a survey of recruitment amongst a cohort of 41 randomised controlled trials in the USA found that 34% recruited less than 75% of their planned sample [3]. The effect of reducing the sample size is to reduce the statistical power of the study, and is one of the main reasons for abandoning trials early 2, 4, 5, 6.
Previous reviews of barriers to recruitment have taken a traditional approach, rather than using a systematic methodology 1, 2, in which the selection, evaluation and inclusion criteria are not explicitly pre-defined. For this reason, such reviews may be biased. We report a systematic literature review of barriers to clinician and patient participation in randomised trials, and make recommendations for improving the conduct of trials based on the findings.
Section snippets
Method
An initial systematic search of Medline, Embase, and CINAHL for the period 1986 to 1996 identified 9732 references of possible relevance to problems associated with the design, conduct, analysis or costs of a trial: of these, 265 papers identified clinician participation or patient participation as being an important issue. From this sub-set, all primary research papers were selected which reported findings relating to problems with recruitment of clinicians or patients to clinical trials: only
Results
Brief descriptions of all the reports included in the review are presented in Table 1.
Discussion
Our review took a systematic approach designed to be less selective and therefore less biased than other less rigorous approaches [85]. The review identified many barriers to clinician and patient recruitment to randomised controlled trials confirming the persistent problems identified in other apparently less systematically conducted work 1, 2, 86.
The findings of our review should be read with some caution, however. In particular, several sources of potential bias are inherent in the material
Acknowledgements
Thanks to David Stephen and Neil Scott for assistance in reviewing the references, to Louise Smith for secretarial help, and to Sandra Kaiuka and Iain Colthart who conducted the original search and initial screening of papers. Carl Counsell was funded as a Wellcome Trust Training Fellow. The literature review was funded by the NHS Executive R&D Research Methodology Programme, and the Health Services Research Unit is core-funded by the Scottish Office Department of Health. However, the views
References (86)
- et al.
The impact of disease severity on the informed consent process in clinical research
Am J Med
(1996) - et al.
Enrollment in clinical trialsInstitutional factors affecting enrollment in the cardiac arrhythmia suppression trial (CAST)
Control Clin Trials
(1992) - et al.
Issues of recruitment, retention, and compliance in community-based clinical trials with traditionally underserved populations
Appl Nurs Res
(1995) - et al.
Reasons for declining participation in a prospective randomized trial to determine the optimum mode of delivery of the preterm breech
Control Clin Trials
(1990) - et al.
Patient perception of a long-term clinical trialExperience using a close-out questionnaire in the Studies of Left Ventricular dysfunction (SOLVD) trial
Control Clin Trials
(1994) Integrating conflicting professional rolesPhysician participation in randomized clinical trials
Soc Sci Med
(1992)- et al.
Informed consent in European Multicentre randomised clinical trials—Are patients really informed?
Eur J Cancer
(1994) - et al.
Informed versus randomised consent to clinical trials
Lancet
(1995) - et al.
Who say yes? Identifying selection biases in a psychosocial intervention study of multiple sclerosis
Soc Sci Med
(1995) - et al.
Reasons related to adherence in community-based field studies
Patient Education & Counselling
(1992)
Patient and clinical factors predictive of missed visits and inactive status in a multicenter clinical trial. The Macular Photocoagulation Study Group
Control Clin Trials
Information for cancer patients entering a clinical trial—An evaluation of an information strategy
Eur J Cancer
Motivation of subjects to participate in a research trial
Appl Nurs Res
Parental perceptions and attitudes about informed consent in clinical research involving children
Soc Sci Med
Effects of two formats of informed consent on knowledge amongst persons with advanced HIV disease in a clinical trial of didanosine
Patient Education & Counselling
Patients' willingness to enter clinical trialsMeasuring the association with perceived benefit and preference for decision participation
Soc Sci Med
Presenting clinical trial informationA comparison of methods
Patient Education & Counseling
The adequacy of consent forms for informing patients entering oncological clinical trials
Ann Oncol
Suspended judgement. Clinical trials of informed consent
Control Clin Trials
Variations in breast cancer treatment decisions and their impact in mounting trials
Control Clin Trials
Recruiting minorities into clinical trialsToward a participant-friendly system
J Natl Cancer Inst
Recruitment experience in clinical trialsliterature summary and annotated bibliography
Control Clin Trials
Applying results of randomised trials to clinical practiceimpact of losses before randomisation
BMJ
Fate of research studies
J R Soc Med
Implementation issues and techniques in randomized trials of outpatient psychosocial treatments for drug abusersrecruitment of subjects
Am J Drug Alcohol Abuse
The recruitment of research participantsa review
Social Work in Health Care
Telephone-based nursing intervention improves the effectiveness of the informed consent process in cancer clinical trials
J Clin Oncol
Clinical research in the NHS today
J R Coll Physicians Lond
Improving accrual into cancer clinical trials
J Cancer Educ
Conducting clinical research in the new NHSThe model of cancer. United Kingdom Coordinating Committee on Cancer Research
BMJ
Oncologists' reluctance to accrue patient onto clinical trialsAn Illinois Cancer Center Study
J Clin Oncol
Clinical trials in cancer therapyEfforts to improve patient enrollment by community oncologists
Med Pediatr Oncol
The doctor's dilemmaPhysician participation in randomized clinical trials
Cancer Treat Rep
Physicians' reasons for not entering eligible patients in a randomized clinical trial of surgery for breast cancer
N Engl J Med
Interpreting physician participation in randomized clinical trialsThe physician orientation profile
J Health Soc Behav
Physician participation in a randomized clinical trial for ocular melanoma
Ann Opthalmol
Fundamental dilemmas of the randomized clinical trial processResults of a survey of the 1,737 Eastern Cooperative Oncology Group investigators
J Clin Oncol
Randomised clinical trials in general practiceLessons from a failure
BMJ
An evaluation of physician determinants in the referral of patients for cancer clinical trials in the community setting
Prog Clin Biol Res
Recruitment in a primary care trial on smoking cessation
Fam Med
Physician response to informed consent regulations for randomized clinical trials
Cancer
Doctor-patient communication about breast cancer adjuvant therapy
J Clin Oncol
Why are (or are not) patients given the option to enter clinical trials?
Control Clin Trials
Cited by (757)
Trial staff and community member perceptions of barriers and solutions to improving racial and ethnic diversity in clinical trial participation; a mixed method study
2024, Contemporary Clinical Trials CommunicationsBuilding Capacity for Pragmatic Trials of Digital Technology in Primary Care
2024, Mayo Clinic ProceedingsDemographic reporting and language exclusion in gynecologic oncology clinical trials
2024, American Journal of Obstetrics and GynecologyCapturing patients’ satisfaction and experiences with suicide prevention in general practice: A bridge too far?
2023, Journal of Affective Disorders Reports