This is a 12-month longitudinal intervention study in adults (18-65 years) with moderate-severe IBS (IBS-SSS ≥175) evaluating a personalized, patient-centered multidisciplinary treatment delivered in a Swedish tertiary care setting. The program includes an internet-based IBS school followed by four evidence-based modules (physician-led medical management/education, dietician-led dietary intervention, psychologist-led IBS-focused behavioral therapy, and physiotherapy) delivered in a sequence chosen by the participant, with symptom evaluation after each module. Outcomes are assessed before and after treatment, with the primary endpoint defined as treatment response (IBS-SSS reduction ≥50 points), and secondary endpoints covering symptom/psychological measures, visceral sensitivity and biological stress plus gut biomarkers, and multimodal brain imaging (structural MRI, rs-fMRI, task fMRI, and insula MRS).
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
OTHER
Masking
NONE
Enrollment
150
Individualized medical management by a gastroenterologist targeting predominant IBS symptoms (pain, diarrhea/constipation, bloating) with evidence-based pharmacological and bowel-regulation strategies as needed.
Individualized dietician guided treatment with either lowFODMAP diet or traditional IBS dietary advice.
Evidence-based psychological treatment for IBS (e.g., CBT/IBS-focused behavioral therapy) targeting symptom-related anxiety, stress, coping strategies, and gut-brain symptom amplification.
Targeted physiotherapy addressing pain modulation and bodily stress responses, including education and individualized exercises/relaxation strategies to improve symptom management and functional capacity. In case of fecal incontinence and pelvic floor dysynergia biofeedback was administrated.
Linköping University Hospital
Linköping, Linköping, Sweden
IBS symptom severity score
The primary outcome was treatment response, defined as a reduction of ≥50 points in the IBS Symptom Severity Score (IBS-SSS). Participants achieving this reduction were classified as responders.
Time frame: From enrollment through 1 year after completion of multimodal, multidisciplinary treatment.
Changes in Gastrointestinal symptom severity
Change from baseline in gastrointestinal symptom severity measured using the Gastrointestinal Symptom Rating Scale for IBS (GSRS-IBS), with higher scores indicating more severe gastrointestinal symptoms).
Time frame: Baseline, 3, 6, 9, and 12 months
Psychological symptom burden
Change from baseline in anxiety and depression measured by the Hospital Anxiety and Depression Scale (HADS). The scale consists of two subscales (anxiety and depression), each ranging from 0 to 21, with higher scores indicating greater symptom severity.
Time frame: At the baseline, 3 months, 6 months, 9 months and end of intervention (12 months)
Visceral sensitivity index (VSI)
Change from baseline in visceral anxiety measured by the Visceral Sensitivity Index (VSI). The total score ranges from 0 to 75, with higher scores indicating greater gastrointestinal-specific anxiety.
Time frame: Baseline, 3, 6, 9, and 12 months
Changes in Gut-brain axis physiology
Change from baseline in rectal sensory thresholds measured using rectal barostat testing. Thresholds will be expressed as pressure and/or volume at first sensation, urge, and maximum tolerable distension. Change from baseline in intestinal permeability measured using Ussing chamber assessment of mucosal permeability. Results will be expressed according to the laboratory-specific permeability measure used.
Time frame: Baseline and 12 months.
Brain imaging outcomes - Brain Structure
Change from baseline in regional gray matter volume measured using structural magnetic resonance imaging (MRI).
Time frame: At the baseline and after 12 months.
Brain imaging outcomes - Brain neurochemistry
Change from baseline in brain metabolite, in insula, such as GABA concentrations measured using magnetic resonance spectroscopy (MRS).
Time frame: Baseline and 12 months.
Brain imaging outcomes - Brain function (BOLD signal activity)
Change from baseline in brain activity measured using functional magnetic resonance imaging (fMRI).
Time frame: Baseline and 12 months.
Serum vasoactive intestinal peptide (VIP) and inflammatory marker concentrations
Change from baseline in serum vasoactive intestinal peptide (VIP) and inflammatory marker concentrations, including tumor necrosis factor alpha (TNF-α).
Time frame: Baseline and 12 months.
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