Study Design
This is a pragmatic, multicentre, randomised controlled trial. Children (aged 6-17 years) with CD, clinically responding to EEN, were recruited prospectively from 11 paediatric hospitals across the UK (Glasgow, Edinburgh, Forth Valley, Wishaw, Crosshouse, Dundee, Aberdeen, Manchester, Birmingham, Sheffield, Royal London). Patients were randomised to the CD-TREAT diet or their unrestricted diet for 21 days immediately following EEN completion. Participants in the intervention group consumed the CD-TREAT diet exclusively without being allowed to consume additional food, for the first 3 weeks of food reintroduction, after EEN completion. They were provided with a tailored, dietitian-devised diet, which has been designed to replicate the nutritional composition of EEN. Participants in the control group consumed their unrestricted diet for the same period.
Participants in both groups recorded their diet on a daily basis using CD-TREAT food checklists (CD-TREAT group) and estimated weight food diaries (unrestricted diet group). Each patient was asked to provide eight consecutive pairs of faecal and urine samples. Samples were collected at baseline (EEN completion), roughly every three days for 21 days, and at day 30 after EEN completion (Fig. 1). Collection of 2 blood samples, anthropometric measurements and assessment of disease activity and quality of life were performed at baseline and at day 21 following EEN completion. Participants were also followed up until they clinically relapsed or for a maximum of one year after EEN completion. Healthy children were recruited from the community and were asked to provide a single stool and urine sample.
Fig. 1 IPENS study design
The primary outcome measure is the association of dietary components with faecal calprotectin levels throughout food reintroduction. Secondary outcomes include association with the gut microbiome, metabolome and immune host factors and the assessment of the efficacy of CD-TREAT as a food reintroduction protocol.
Results
Recruitment is now completed, and data analysis is underway. A total of 174 participants (116 patients with Crohn’s disease and 58 healthy controls) were recruited. Of those, 103 patients completed the trial, 7 patients deteriorated rapidly, and 6 patients dropped out (overall 5% drop-out rate). Out of the 58 healthy controls, 56 completed the study. In total, we collected 899/926 (97%) of expected stool samples, 890/926 (96%) of expected urine samples and 207/223 (93%) of expected blood samples.