Patient recruitment to a diabetic retinopathy screening trial through optimised patient information materials:an embedded study within a trial (SWAT)

Background: Printed participant information about trials is often technical, long and difficult to navigate. Optimisation and user testing can improve information materials, and may improve participant understanding and rates of recruitment. Methods: A study within a trial (SWAT) was undertaken within the ISDR trial. Potential participants in the ISDR trial were randomised to receive either the standard trial information or revised information that had been optimised through information design and user testing. Results: A total of 3,169 patients were randomised in the SWAT. Recruitment rates to the ISDR trial were 25.3% in the optimised information group and 26.1% in the standard information group (odds ratio 0.951; 95% CI 0.752 to 1.201; p=0.672). Clinic attendance rates were 71.6% in the optimised information group and 69.3% in the standard information group (OR 1.145; 95% CI 0.885 to 1.480; p=0.304). Conclusions: Optimisation of participant information through information design and user testing did not affect rate of recruitment to the host ISDR trial.