A randomized, embedded trial of pre-notification of trial participation did not increase recruitment rates to a falls prevention trial.
OBJECTIVE
To design and evaluate the effectiveness of a pre-notification leaflet about research to increase recruitment to a randomized controlled trial (RCT).


METHODS
A methodological, two-arm, RCT was conducted, embedded within an existing cohort RCT (REFORM). Participants were randomized for the embedded trial, using a 1:2 ratio (intervention : control) before being randomized for REFORM. Controls received a trial recruitment pack. The intervention group received an additional pre-notification leaflet 2-3 weeks before the recruitment pack. Primary and secondary analyses were conducted using relative risk, the Cox proportional hazards model and incremental cost-effectiveness ratios.


RESULTS
Of the 1436 intervention group participants, 73 (5.1%) were randomized into the REFORM trial compared with 126 (4.4%) of the 2878 control group participants. The associated relative risk (1.16) was not statistically significant [95% confidence interval (CI) 0.88-1.56]. Return rate was not significantly increased (relative risk 1.10, 95% CI 0.92-1.28) nor time to return decreased (hazard ratio: 1.11, 95% CI 0.93-1.33). Incremental cost-effectiveness ratios indicated the intervention may be cost-effective if the true estimate of effect was close to the upper bound of the associated 95% CI.


CONCLUSIONS
Pre-notification for potential trial participants demonstrated a small difference to randomization (0.7% difference) and return rates (1.1% difference) in favour of the intervention. Results should however be interpreted with caution as CIs for these estimates cross the point of no effect. Nevertheless, this research enhances existing evidence for pre-notification to increase recruitment rates, with further development and assessment of this potentially cost-effective intervention being recommended.
York Trials Unit - Department of Health Sciences, The University of York, York, UK.
Catherine
C
Arundel
York Trials Unit - Department of Health Sciences, The University of York, York, UK.
Laura
L
Jefferson
York Trials Unit - Department of Health Sciences, The University of York, York, UK.
Matthew
M
Bailey
York Trials Unit - Department of Health Sciences, The University of York, York, UK.
Sarah
S
Cockayne
York Trials Unit - Department of Health Sciences, The University of York, York, UK.
Kate
K
Hicks
York Trials Unit - Department of Health Sciences, The University of York, York, UK.
Lorraine
L
Loughrey
York Trials Unit - Department of Health Sciences, The University of York, York, UK.
Sara
S
Rodgers
York Trials Unit - Department of Health Sciences, The University of York, York, UK.
David J
DJ
Torgerson
York Trials Unit - Department of Health Sciences, The University of York, York, UK.
D000058:Accidental Falls / Q000517:prevention & control*; D000368:Aged; D000369:Aged, 80 and over; D003142:Communication; D003362:Cost-Benefit Analysis; D005260:Female; D006801:Humans; D008297:Male; D018579:Patient Selection; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic / Q000191:economics* / Q000379:methods*
embedded trial; leaflet; pre-notification; randomization; randomized controlled trial; recruitment