Three controlled trials of interventions to increase recruitment to a randomized controlled trial of mobile phone based smoking cessation support.
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2010-05-20
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Abstract
BACKGROUND Recruitment is a major challenge for trials but there is little evidence regarding interventions to increase trial recruitment We report three controlled trials of interventions to increase recruitment to the Txt2stop trial PURPOSE To evaluate Trial 1 The impact on registrations of a text message regarding an online registration facility Trial 2 The impact on randomizations of sending pound5 with a covering letter to those eligible to join the trial Trial 3 The impact on randomizations of text messages containing quotes from existing participants METHODS Single blind controlled trials with allocation concealment INTERVENTIONS Trial 1 A text message regarding our new online registration facility Trial 2 A letter with pound5 enclosed Trial 3 A series of four text messages containing quotes from participants The control group in each trial received standard Txt2stop procedures RESULTS Trial 1 3 6 17 470 of the intervention group and 1 1 5 467 of the control group registered for the trial risk difference 2 5 95 CI 0 6 4 5 0 0 470 of the intervention group and 0 2 1 467 of the control group registered successfully online risk difference 0 2 95 CI 0 6 0 2 Trial 2 4 5 11 246 of the intervention group and 0 4 1 245 of the control group were randomized into the Txt2stop trial risk difference 4 0 95 CI 1 4 6 7 Trial 3 3 5 14 405 of the intervention group and 0 0 406 of the control group were randomized into the Txt2stop trial risk difference 3 5 95 CI 1 7 5 2 LIMITATIONS There were no baseline data available for trial 1 Allocation of participant IDs in trials 2 and 3 were systematic CONCLUSION Sending a text message about an online registration facility increased registrations to Txt2stop but did not increase online registrations Sending a pound5 reimbursement for participants time and sending text messages containing quotes from existing participants increased randomizations into the Txt2stop trial Clinical Trials 2010 7 265 273 http ctj sagepub com