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Table 1 Deriving the factors affecting recruitment from facilitators and from barriers described in literature

From: Developing a survey of barriers and facilitators to recruitment in randomized controlled trials

Prescott et al. [[37]]

Barriers to participation in clinical trials: patient and clinician barriers

Barriers

Classification

Factor derived

Patient barriers

Additional demands of the randomized controlled trials (RCT) on the patient

Patient level factors

Additional trial investigations

Additional procedures, additional appointments, time pressures, venepuncture, inpatient hospital stays, discomfort from medical procedures, length of study, worry about experimentation, uncomfortable procedures, travel and travel costs, extra costs

Additional travel and extra costs

Duration of trial and follow- up

Patient preference for a particular treatment

Patient level factors

Patients’/parents’ preference for a particular treatment

Patients not wanting to change medication, not to take placebo, not to take experimental medication, not to take any medication, patient request for a specific intervention, strong patient preference for one treatment option

Patients’/parents’ attitudes towards taking experimental medicine or placebo

Aversion to treatment choice by random allocation

Treatment choice by random allocation

Worry about uncertainty

Patient level factors

Patients’/parents’ concerns about side effects of new drug

Efficacy of treatment on offer is unproven, distrust of hospital or medicine, fear of unknown

Concerns about information and consent

Information and consent related factors

Amount and complexity of trial information provided

Amount of information provided to research participants, wording of information, complexity of information provided, different forms of information presentation: written /verbal/video, limited reading skills and English not being the primary language, clinicians’ experience, difficulty in giving information, worry about level of information required and that information may be frightening, consent procedure barrier to recruitment

Patient level factors

Clarity in presentation of trial information

Clinical team factors

Experience and training of clinical team seeking consent

Social and emotional dynamics of trial discussion

Consent rate

Language or cultural barrier

Difficulty in approaching patents for consent

Clinician barriers

Time constraints

Clinical team factors

Clinical workload

Time pressures from usual clinical practice, time demands of recruitment and follow-up

Staffing and training

Clinical team factors

Research experience of clinical team

Lack of trained staff, no additional support, lack of research experience in clinicians, lack of available support staff

Availability of designated research team

Availability of research staff out of hours

Presence of designated research nurse/practitioner

Rewards and recognition

Excluded

Information available from the Chief Investigator

Economic incentives

Impact on doctor patient relationship fear of Adverse effect on doctor-patient relationship, perceived conflict in their role as clinicians and researchers

Clinical team factors

Clinician attitude to involving patients in research

Concern for patients

Concern about treatment toxicity, side effects, burden of trial for patients including travel distance and costs, reluctance to recruit severely ill patients

Problems in complying with the protocol

Clinical team factor

Clinician preference for a particular treatment

Trial level factor

Study protocol compared to clinical practice

Campbell et al. [[38]]

Hypothesis of factors tested for association with recruitment success

Trials with complex trial design do not recruit as well as simple trials

Trial level factor

Trial design

Less well-funded trials do not recruit well

Trial level factor

Funding

Trials without dedicated trial management expertise do not recruit as well as those with trial management expertise

Trial level factor

Trial management

Trial with multidisciplinary input recruit better than those that do not have this input

Excluded

Information available from the Chief Investigator

Trials with consumer involvement recruit better than those that do not

Excluded

Information available from the Chief Investigator

Trials that have a successful pilot phase recruit better than those that do not have a pilot phase

Trial level factor

Previous feasibility assessment

Previous pilot trial

Trials that have dedicated paid local coordinators recruit better than those that do not

 

Trial management

Cancer trials recruit better than non cancer trials

Trial level factor

Being a drug/cancer trial

Drug trials recruit better than non-drug trials

 

Being a drug/cancer trial

Trials funded through a response-mode funding have different recruitment rates to those funded through a commissioned process

Trial level factor

Funding

Reasons for delays in recruitment to the included cohort of trials

Problems with central staff, local research staff, internal problems (for example, staff)

Site level factor

Number of trained staff

Clinical team factor

Motivation of clinical team

Local clinical arrangements, merging/reorganization of trusts, major relocation of services, department policies

Site level factor

Local clinical arrangements

Funding issues

Trial level factor

Funding

Delays in ethical clearance

Excluded

Information available from the Chief Investigator

Research and Development (R&D) delays, time delay since grant application

Delays in supply of drug/placebo

Excluded

Information available from the Chief Investigator

Adverse publicity about medical research, external problem (for example, publicity)

Trial level factor

Publicity by the trial team

External publicity

Setting up general practitioner (GP) practices took longer than anticipated

Site level factor

Time to open up site

Simultaneous other local research projects, competing research, conflict with other trials

Site level factor

Competing local research projects

Delays due to changes in data legislation, changes in technology

Excluded

Information available from the Chief Investigator

Fewer eligible than expected, smaller percentage agreeing to participate, recruitment targets too ambitious

Trial level factor

Lack of pilot/feasibility assessment

Site level factor

Recruitment target

Absence of perceived clinical equipoise

Trial level factor

Clinical equipoise

Issues with procedures/interventions, trial process too demanding

Patient level factor

Additional trial investigations

Complexity of trial design, trial methodology considered too complex

Trial level factor

Trial design

Conflicting workload pressures, long waiting lists, additional theatre time required

Clinical team factor

Clinical workload

Language/written English difficulties

Patient level factor

Language or cultural barrier

Treatment preferences

Patient level factor

Patients’/parents’ preference for a particular treatment

Clinical team factor

Clinician preference for particular treatment

Research not considered as priority

Clinical team factor

Perceived importance of research generally in clinical practice

Perceived importance of the particular research question

No local access to intervention

Patient level factor

Intervention available only in the trial

Case studies of trials: common factors in the successes of part B trials

Facilitator

Classification

Factor derived

Important/interesting research question, topic important, urgent need for research, important question, timely and managed to roll several questions into one study

Clinical team factor

Perceived importance of the particular research question

Good design/good protocol, pragmatic study

Trial level factor

Trial design

Study protocol compared to clinical practice

Clinicians keen to recruit to trial

Clinical team factor

Motivation of clinical team

Clinician attitude to involving patients in research

Drugs already tested, so easy to explain to patients

Patient level factor

Familiarity with experimental treatment

Did not demand extra effort from patients, Impact on practice running and costs minimized, minimizing work for health professionals

Patient level factor

Additional trial demands

No competing trials for those centers/patients

Site level factor

Competing local research projects

Drugs not available outside the trial

Patient level factor

Intervention available only in the trial

Excellent trial management, trial units helpful, caring, annual meetings for all concerned, role of trial steering group

Trial level factor

Trial management

Good planning and organization by Clinical Trials Support Unit (CTSU), CTSU responsive, efficient, central organization of many aspects of research

Good communication between trial team and clinicians, flexibility of trial teams

Study team factor

Communication and coordination among study team members at site

Good public relations/feedback/updates

Trial level factor

Trial publicity

Good funding, National Health Service (NHS) funding

Trial level factor

Funding

Trial run by good team/infrastructure, Principal Investigator (PI) well respected, PIs worked hard to keep collaborators on board, trial team communicative, responsive and alert to problems. Communication within team, between team and collaborating clinicians

Study team factors

Motivation of the study team at site

Clinical team factor

Research experience of PI and study team members at site

Good trial team, good research assistants

Communication and coordination among study team members at site

Team worked hard at how to explain the study to patients

Communication and coordination between study team at site and Clinical Trials Unit (CTU)

Research experience of clinical team

Communication skills of clinical team

Role of research nurse

Clinical team factor

Presence of designated research nurse/practitioner

Study included everybody

Trial level factor

Patient inclusion criteria

Toerien et al . [[39]]

Study design, number of arms, control: active/placebo

Trial level factor

Trial design

Single/multicenter

Excluded

Information will be present

Intervention: drug/surgery/allied/others

Trial level factor

Being a drug/cancer/surgical/-----trial

Funding source

Trial level factor

Funding

Caldwell et al . [[40]]

  

Recruitment strategies

Novel trial designs

Trial level factor

Trial design

Recruiter differences

Information and consent related factors

Experience and training of doctors clinical team seeking consent

Senior doctors and nurses seeking consent

Financial incentives for patients/participants

Excluded

Monetary incentives not acceptable for clinical research in United Kingdom

Methods of providing information

Information and consent related factors

Amount and complexity of information provided

Patient level factor

Clarity in presentation of trial information

Consent rate

Treweek et al . [[2]]

  

Recruitment strategies

  

Design changes

Trial level factor

Trial design

Modification to the consent form or process

Patient level factor

Consent rate

Modification to the approach made to potential participants

Information and consent related factors

Amount and complexity of information provided

Clarity in presentation of trial information

Senior doctors and nurses seeking consent

Financial incentives for patients/participants

Excluded

Monetary incentives not acceptable for clinical research in United Kingdom

Modification to the training given to recruiters

Information and consent related factors

Experience and training of clinical team seeking consent

Greater contact between trial coordinator and trial sites

Trial level factor

Trial management