1. Gloucestershire Royal Hospital, Great Western Road, Gloucester, GL1 3NN
2. Division of Gastroenterology, McMaster University Medical Centre, 1200 Main Street West, Hamilton, Ontario, Canada L8N 3Z5
3. Centre for Statistics in Medicine, University of Oxford, Botnar Research Centre, Windmill Road, Oxford, OX3 7LD
4. University of Glasgow, Health Economics and Health Technology Assessment, Institute of Health & Wellbeing, 1 Lilybank Gardens, Glasgow G12 8RZ
5. University Hospitals Coventry and Warwickshire, University of Warwick, Warwickshire, CV2 2DX