Patterns of enrollment in randomized and preference trials of behavioral treatments for insomnia

Abstract

Participants’ preferences for treatment may deter enrollment in a randomized clinical trial (RCT). The Partially randomized clinical trial (PRCT) is proposed as an alternative design to increase enrollment rate and enhance representativeness of the sample. There is limited evidence supporting the advantages of the PRCT. This study aimed to examine enrollment and refusal rates, reasons for refusal, and clinical profile of persons who declined participation and those who enrolled, in the context of a RCT and a PRCT. Persons with chronic insomnia completed a questionnaire to determine if they met the eligibility criteria regarding type, frequency, and duration of insomnia. Those who declined participation indicated reasons for refusal. Enrollment rate was computed as the percentage of individuals who took part in the study out of those found eligible. Independent sample t-test was used to compare enrollees and non-enrollees on characteristics of insomnia. The results showed a higher enrollment rate in the RCT than PRCT. Reasons for refusal were similar under the RCT and PRCT. Significant differences between enrollees and non-enrollees were found on fewer characteristics in the RCT than PRCT. The results do not support the advantages of the PRCT in enhancing enrollment of participants in studies evaluating the effectiveness of behavioral treatments of chronic insomnia.