Non-drug therapies for the management of chronic constipation in adults: the CapaCiTY research programme including three RCTs

Background: Chronic constipation affects 1–2% of adults and significantly affects quality of life. Beyond the use of laxatives and other basic measures, there is uncertainty about management, including the value of specialist investigations, equipment-intensive therapies using biofeedback, transanal irrigation and surgery. Objectives: (1) To determine whether or not standardised specialist-led habit training plus pelvic floor retraining using computer-assisted direct visual biofeedback is more clinically effective than standardised specialist-led habit training alone, and whether or not outcomes of such specialist-led interventions are improved by stratification to habit training plus pelvic floor retraining using computer-assisted direct visual biofeedback or habit training alone based on prior knowledge of anorectal and colonic pathophysiology using standardised radiophysiological investigations; (2) to compare the impact of transanal irrigation initiated with low-volume and high-volume systems on patient disease-specific quality of life; and (3) to determine the clinical efficacy of laparoscopic ventral mesh rectopexy compared with controls at short-term follow-up. Design: The Chronic Constipation Treatment Pathway (CapaCiTY) research programme was a programme of national recruitment with a standardised methodological framework (i.e. eligibility, baseline phenotyping and standardised outcomes) for three randomised trials: a parallel three-group trial, permitting two randomised comparisons (CapaCiTY trial 1), a parallel two-group trial (CapaCiTY trial 2) and a stepped-wedge (individual-level) three-group trial (CapaCiTY trial 3). Setting: Specialist hospital centres across England, with a mix of urban and rural referral bases. Participants: The main inclusion criteria were as follows: age 18–70 years, participant self-reported problematic constipation, symptom onset > 6 months before recruitment, symptoms meeting the American College of Gastroenterology’s constipation definition and constipation that failed treatment to a minimum basic standard. The main exclusion criteria were secondary constipation and previous experience of study interventions. Interventions: CapaCiTY trial 1: group 1 – standardised specialist-led habit training alone (n = 68); group 2 – standardised specialist-led habit training plus pelvic floor retraining using computer-assisted direct visual biofeedback (n = 68); and group 3 – standardised radiophysiological investigations-guided