Increasing recruitment to randomised trials: a review of randomised controlled trials.
BACKGROUND
Poor recruitment to randomised controlled trials (RCTs) is a widespread and important problem. With poor recruitment being such an important issue with respect to the conduct of randomised trials, a systematic review of controlled trials on recruitment methods was undertaken in order to identify strategies that are effective.


METHODS
We searched the register of trials in Cochrane library from 1996 to end of 2004. We also searched Web of Science for 2004. Additional trials were identified from personal knowledge. Included studies had to use random allocation and participants had to be allocated to different methods of recruitment to a 'real' randomised trial. Trials that randomised participants to 'mock' trials and trials of recruitment to non-randomised studies (e.g., case control studies) were excluded. Information on the study design, intervention and control, and number of patients recruited was extracted by the 2 authors.


RESULTS
We identified 14 papers describing 20 different interventions. Effective interventions included: telephone reminders; questionnaire inclusion; monetary incentives; using an 'open' rather than placebo design; and making trial materials culturally sensitive.


CONCLUSIONS
Few trials have been undertaken to test interventions to improve trial recruitment. There is an urgent need for more RCTs of recruitment strategies.
Watson
Judith M
JM
York Trials Unit, Department of Health Sciences, University of York, York, YO10 5DD, UK. jmw19@york.ac.uk
Torgerson
David J
DJ
D003469:Culture; D006801:Humans; D018579:Patient Selection; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D012042:Registries; D035842:Research Subjects