Factors Affecting Recruitment to Trial in General Practice: A Systematic Review

Problem

The aim of this systematic review is to identify factors associated with recruitment of individuals and practices to RCTs in general practice. While this will be of more general interest, we will use the findings from this to inform the development of a predictive model of recruitment to RCTs in general practice.

Approach

The protocol has been registered with PROSPERO (registration number: CRD42018100695) and published in BMC Trials with the completed PRISMA-P checklist.

Any primary study design that investigated recruitment to RCTs where the intervention was based in in general practice was included.

MEDLINE, Embase, Cochrane Database of Systematic Reviews, OpenGrey, National Technical Reports Library. The journal BMC trials was hand searched.

Titles and abstracts of studies found using the search strategy and from other sources were independently screened by two reviewers. The full text of those studies that potentially met the inclusion criteria were retrieved and independently assessed for eligibility by two reviewers.

Two review authors (KM and WS) extracted data independently from included studies and conflicts were resolved through discussion.

Two reviewers independently assessed study quality (KM and WS).

A narrative synthesis of the included studies was performed.

Findings

Analysis of the included studies is not yet complete. We have completed tabulation of the summary characteristics for the included papers and will soon being collation of quality appraisal outcomes and then analysis of the included papers. We aim to have this completed by the time of the conference.

Results of the search:

The search resulted in 7297 papers. After Title and abstract screening, and full text screening 37 studies were included.

Initial conclusions:

1. Studies investigating recruitment to trials in GP are generally of low quality. This reflects the fact that most recruitment studies arise out of difficulty in recruiting and are descriptive in nature, rather than having been planned in advance of the RCT and rigorously designed.

2. There are many factors that have been investigated in relation to recruitment. We will analyse these in advance of the conference.

Consequences

1. Trialists should recognise trial recruitment as a ubiquituous threat. They should use existing evidence to inform the design of their trial, however since this is largely lacking, where feasible they should embed a rigorously designed recruitment study to improve the evidence base and more comprehensively inform future trials. The Studies Within A Trial (SWAT) approach is important here.

2. Researchers should carefully consider the need for further low-quality descriptive recruitment studies that do not add to the evidence base. Adequate resourcing of research teams by funders to study recruitment could ensure researchers use their time producing research of greater importance.

3. Implications of the specific factors affecting recruitment will be discussed once analysed.