Psychological distress predicts disease activity in inflammatory bowel disease: Results from the mind-body IBD longitudinal study

Background & aims: Psychological distress (depression, anxiety, stress) is common in inflammatory bowel disease (IBD) and is linked to poorer outcomes, yet behavioural pathways and economic consequences remain unclear. This study tested a gut-brain-behaviour-outcome (GBBO) framework, testing: 1) reciprocal links between distress and disease activity; 2) whether health behaviours mediate distress-disease activity relationships; 3) if distress and self-reported disease activity (SRDA) predict adverse disease outcomes, controlling for inflammation and 4) whether disease activity mediates relationships between distress and adverse outcomes. Methods: IBD patients (n = 157) reported distress, health behaviours, SRDA, healthcare use and disease-related outcomes at 3 waves at 6-month intervals. Faecal calprotectin (FCP) was assayed at baseline and 6 months. Analyses were conducted using structural equation modelling and mixed-effects models. Results: 04). Other behaviours were nonsignificant. Controlling for FCP, distress and SRDA independently predicted secondary healthcare usage (primary/secondary care) and disease-related outcomes (flare frequency/severity, absenteeism and productivity loss). FCP was positively related to flare frequency/severity and allied health practitioner visits only. Mediation analysis showed that SRDA partially mediated absenteeism. Conclusions: Psychological distress exacerbates symptoms and economic cost. Poor sleep partially mediates the relationship between distress and SRDA, but not inflammation. Psychological interventions that focus on improving sleep could be cost-effective ways to improve mental health and symptom burden, with downstream impact on healthcare utilisation and productivity losses.