Body Composition Assessment and Monitoring in Inflammatory Bowel Disease

Body Composition Assessment and Monitoring With Bioelectrical Impedance Analysis to Predict Medical Therapy Efficacy in Inflammatory Bowel Disease (the BAMBIE Study)

This is a single-center, prospective observational study aiming to describe changes in body composition (specifically, percentage of lean mass and phase angle) in patients with active inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease.

The study will recruit patients with a confirmed IBD diagnosis who are starting biologic therapy or Janus kinase inhibitors (JAKi) to induce clinical remission. Body composition will be assessed using bioelectrical impedance analysis (BIA) at baseline (time 0), 24 weeks, and 52 weeks after starting medication. Clinical disease activity, endoscopic findings, and laboratory data will also be collected at various time points if available.

The study has a total duration of 36 months, including a 12-18 month patient inclusion period and a 12-month follow-up. Patients will provide informed consent, and all treatment decisions will follow standard clinical practice, as this is a non-interventional observational study.

Inclusion Criteria:

• Any sex.
• Age between 18 and 64 years.
• Patients with a definitive diagnosis (>3 months) of Crohn's disease or ulcerative colitis, according to European Crohn's and Colitis Organization criteria.
• Moderate-to-severe disease luminal activity, with an indication for biologic or JAKi therapy for the induction of clinical remission.

Exclusion Criteria:

• Unclassified IBD.
• History of intestinal resection for IBD, with the exception of ileocecal resection.
• Short bowel syndrome.
• Indication for medical treatment due to postsurgical recurrence.
• Active perianal disease.
• Indication for medical treatment due to intestinal stricture.
• Previous participation in a clinical trial involving medication for IBD treatment.
• Engaging in vigorous physical activity (>6 Metabolic Equivalent of Task, METs) for more than 3 days per week.
• Habitual alcohol consumption (>1 standard drink unit/day).
• Diabetes mellitus with inadequate glycemic control.
• Chronic use of diuretics.
• Chronic kidney disease on dialysis.
• Presence of dependent edema and/or ascites.
• Cardiac pacemaker bearers.
• Pregnant or lactating women.
• Inability to sign informed consent.