3.2.1. Rate of Recruitment, Eligibility, Enrolment, and Retention
RECRUITMENT
A rapid screening phase was first performed. The potential trial participants were familiarized with the list of eligibility criteria in electronic, paper or phone call form, together with information on the purpose and structure of the investigation. A total of 268 subjects were screened between December 2020 and December 2022, and 115 declared an interest in participating (43%). The mean recruitment rate was 4.8 participants per month, ranging from 0 to 27 participants. The main causes of not being recruited given by the subjects were not fulfilling the eligibility criteria (Following this, the inclusion and exclusion criteria were assessed by one of the study investigators during an on-line or in-person meeting. A total of 52% (60/115) of the assessed participants were eligible for enrolment. The enrollment ratio was 100%. The mean enrolment rate was 2.5 per month, ranging from 0 to 11 participants. Thirty-three subjects were allocated to be given the probiotic and 27 to be given the placebo intervention. As this pilot study is an internal part of the full Pro-demet RCT, randomization was performed for the full study, and the numbers of pilot trial participants were not necessarily equal. All participants received the allocated intervention.