Resting Energy Expenditure by Gastrointestinal Functional Status

Comparison of Resting Energy Expenditure According to Gastrointestinal Functional Status

This prospective, comparative interventional study will evaluate resting energy expenditure in adults with different gastrointestinal functional status. A total of 92 participants aged 18 to 65 years will be included: 30 healthy adults with normal gastrointestinal function and 62 patients with clinically confirmed intestinal failure. The intestinal failure group will include patients with short bowel syndrome and patients with other causes of intestinal failure.

Participants will be assigned to one of two protocol-defined groups according to their gastrointestinal functional status. Each participant will attend one study visit lasting approximately 90 to 120 minutes. The research procedures will include measurement of resting energy expenditure by indirect calorimetry after an overnight fast, assessment of body composition by dual-energy X-ray absorptiometry and bioelectrical impedance analysis, and blood sampling for inflammatory markers.

The primary objective is to compare resting energy expenditure between healthy participants and patients with intestinal failure and to determine whether resting energy expenditure differs according to the underlying cause of intestinal failure. Secondary objectives are to evaluate the associations between resting energy expenditure, lean body mass, fat mass, phase angle, and inflammatory markers. The results may contribute to more individualized nutritional management of patients with intestinal failure.

Study Overview

• Status: Recruiting
• Conditions: Short Bowel Syndrome; Intestinal Failure
• Intervention / Treatment: Diagnostic test: Protocol-Defined Metabolic and Body Composition Assessment

Detailed Description

Intestinal failure is a condition in which the gastrointestinal tract is unable to provide adequate digestion and absorption of nutrients, electrolytes, and fluids. Patients may therefore require partial or complete parenteral nutrition. Their resting energy expenditure may be affected by the underlying cause of intestinal failure, changes in body composition, nutritional and metabolic status, and systemic inflammation. Accurate assessment of energy requirements is important for planning individualized nutritional support.

This is a prospective, comparative interventional study with two non-randomized, protocol-defined groups. Group A will include 30 healthy adults with normal gastrointestinal function. Group B will include 62 clinically stable patients with confirmed intestinal failure. Within Group B, approximately 38 participants will have short bowel syndrome and 24 will have other causes of type II or type III intestinal failure, including chronic intestinal dysmotility or extensive disease of the small intestinal mucosa.

The study intervention consists of metabolic, body-composition, and laboratory assessments performed according to a standardized research protocol. Each participant will complete the study during one visit at the Institute of Oncology Ljubljana. The visit will last approximately 90 to 120 minutes. Resting energy expenditure will be measured in the morning, after fasting, in a thermoneutral environment using indirect calorimetry. The indirect calorimetry measurement will last approximately 30 minutes and will determine oxygen consumption and carbon dioxide production.

Body composition will be assessed using dual-energy X-ray absorptiometry to measure lean body mass, fat mass, and bone mineral density. Bioelectrical impedance analysis will also be performed to determine phase angle as an indicator of cellular integrity and function. A blood sample will be collected to assess inflammatory markers, including C-reactive protein and calculated neutrophil-to-lymphocyte, platelet-to-lymphocyte, and lymphocyte-to-monocyte ratios.

Resting energy expenditure will be evaluated as an absolute value in kilocalories per day and in standardized forms, including adjustment for lean body mass, age, and sex. The primary analyses will compare resting energy expenditure between healthy participants and patients with intestinal failure and between patients with short bowel syndrome and patients with other causes of intestinal failure.

Secondary analyses will examine the associations between resting energy expenditure and body-composition parameters, phase angle, and inflammatory markers. The study is intended to improve understanding of metabolic requirements in intestinal failure and to support the development of more individualized nutritional recommendations for these patients.

• Study Type: Interventional
• Enrollment (Estimated): 92
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Klemen Schara, MSc; Phone Number: +38631630065; Email: kschara@onko-i.si

Study Locations

• Slovenia
  • Ljubljana, Slovenia, 1000
    • Recruiting
    • Institute of Oncology Ljubljana
    • Contact: Klemen Salmič, MSc; Phone Number: +386 1 587 9526; Email: kschara@onko-i.si

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

Group A - Healthy Controls:

• Age 18 to 65 years
• No diagnosed chronic diseases
• No hospitalization within the previous 30 days
• No acute illness within the previous 14 days

Group B - Participants With Intestinal Failure:

• Age 18 to 65 years
• Diagnostically confirmed intestinal failure
• Stable clinical condition

Exclusion Criteria:

• Uncontrolled hyperthyroidism or hypothyroidism
• Diabetes mellitus with poor glycemic control
• Adrenal gland disease
• Active inflammatory bowel disease, including Crohn's disease or ulcerative colitis
• Celiac disease
• Chronic pancreatitis
• Active gastric or esophageal disease
• Irritable bowel syndrome with significant symptoms
• History of major abdominal surgery that permanently affects gastrointestinal function, except in participants with intestinal failure when this forms part of the condition under study
• Heart failure
• Active ischemic heart disease or recent myocardial infarction
• Chronic obstructive pulmonary disease
• Respiratory failure or need for long-term oxygen therapy
• Progressive neurodegenerative disease
• Dementia impairing the ability to participate
• Severe stroke with significant functional impairment
• Active tuberculosis
• HIV/AIDS with clinically significant immunosuppression
• Active systemic autoimmune disease
• Active malignant disease
• Advanced liver cirrhosis
• Chronic kidney disease
• Treatment with hemodialysis or peritoneal dialysis
• Pregnancy or breastfeeding

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Healthy Controls; Adults with normal gastrointestinal function who serve as the comparison group. Participants undergo the protocol-defined metabolic, body-composition, and laboratory assessments during a single study visit, including indirect calorimetry after fasting, dual-energy X-ray absorptiometry, bioelectrical impedance analysis, and blood sampling for inflammatory markers.	Diagnostic test: Protocol-Defined Metabolic and Body Composition Assessment; Participants undergo a standardized research assessment during one study visit. Resting energy expenditure is measured by indirect calorimetry after fasting. Body composition is assessed by dual-energy X-ray absorptiometry and bioelectrical impedance analysis. Blood samples are collected for the assessment of inflammatory markers. These assessments are performed outside routine clinical care according to the study protocol.
Experimental: Participants With Intestinal Failure; Adults with clinically confirmed intestinal failure, including participants with short bowel syndrome and participants with other causes of intestinal failure. Participants undergo the protocol-defined metabolic, body-composition, and laboratory assessments during a single study visit, including indirect calorimetry after fasting, dual-energy X-ray absorptiometry, bioelectrical impedance analysis, and blood sampling for inflammatory markers.	Diagnostic test: Protocol-Defined Metabolic and Body Composition Assessment; Participants undergo a standardized research assessment during one study visit. Resting energy expenditure is measured by indirect calorimetry after fasting. Body composition is assessed by dual-energy X-ray absorptiometry and bioelectrical impedance analysis. Blood samples are collected for the assessment of inflammatory markers. These assessments are performed outside routine clinical care according to the study protocol.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Resting Energy Expenditure Measured by Indirect Calorimetry	Resting energy expenditure (REE) will be measured by indirect calorimetry in the morning after fasting and under thermoneutral conditions. The measurement will last approximately 30 minutes and REE will be expressed as an absolute value in kilocalories per day. REE will also be standardized according to lean body mass and evaluated according to age and sex. Values will be compared between healthy controls and participants with intestinal failure, as well as between participants with short bowel syndrome and participants with other causes of intestinal failure.	During the single study visit; REE is assessed over approximately 30 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Lean Body Mass Assessed by Dual-Energy X-Ray Absorptiometry	Lean body mass will be measured by dual-energy X-ray absorptiometry (DXA). The association between lean body mass and resting energy expenditure will be analyzed in all participants.	During the single study visit, lasting approximately 90 to 120 minutes
Fat Mass Assessed by Dual-Energy X-Ray Absorptiometry	Fat mass will be measured by dual-energy X-ray absorptiometry (DXA). The association between fat mass and resting energy expenditure will be analyzed in all participants.	During the single study visit, lasting approximately 90 to 120 minutes
Phase Angle Assessed by Bioelectrical Impedance Analysis	Phase angle will be measured by bioelectrical impedance analysis (BIA) as an indicator of cellular integrity and function. The association between phase angle and resting energy expenditure will be analyzed in healthy controls and participants with intestinal failure.	During the single study visit, lasting approximately 90 to 120 minutes
C-Reactive Protein	C-reactive protein concentration will be determined from a blood sample as a marker of systemic inflammation. Its association with resting energy expenditure will be analyzed in participants with intestinal failure.	During the single study visit, lasting approximately 90 to 120 minutes
Neutrophil-to-Lymphocyte Ratio	The neutrophil-to-lymphocyte ratio will be calculated from blood cell counts as a marker of systemic inflammation. Its association with resting energy expenditure will be analyzed in participants with intestinal failure.	During the single study visit, lasting approximately 90 to 120 minutes
Platelet-to-Lymphocyte Ratio	The platelet-to-lymphocyte ratio will be calculated from blood cell counts as a marker of systemic inflammation. Its association with resting energy expenditure will be analyzed in participants with intestinal failure.	During the single study visit, lasting approximately 90 to 120 minutes
Lymphocyte-to-Monocyte Ratio	The lymphocyte-to-monocyte ratio will be calculated from blood cell counts as a marker of systemic inflammation. Its association with resting energy expenditure will be analyzed in participants with intestinal failure.	During the single study visit, lasting approximately 90 to 120 minutes

Collaborators and Investigators

• Sponsor: Institute of Oncology Ljubljana

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2025
• Primary Completion (Estimated): October 1, 2026
• Study Completion (Estimated): October 1, 2026

Study Registration Dates

• First Submitted: July 15, 2026
• First Submitted That Met QC Criteria: July 15, 2026
• First Posted (Actual): July 20, 2026

Study Record Updates

• Last Update Posted (Actual): July 20, 2026
• Last Update Submitted That Met QC Criteria: July 15, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Body Composition; Resting Energy Expenditure; Dual-Energy X-Ray Absorptiometry; Indirect Calorimetry
• Additional Relevant MeSH Terms: Postoperative Complications; Pathologic Processes; Intestinal Diseases; Digestive System Diseases; Gastrointestinal Diseases; Malabsorption Syndromes; Pathological Conditions, Signs and Symptoms; Intestinal Failure; Short Bowel Syndrome
• Other Study ID Numbers: ORI2025-12

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No