Stool Analysis After Sleeve Gastrectomy vs Gastric Bypass

NCT07461610 | Recruiting

• 1 other identifier: Ms-48-2026
• Study Type: observational
• Target: 50
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this observational study is to learn whether routine stool tests can detect changes in gut function 6 months after two common types of weight loss surgery: sleeve gastrectomy and gastric bypass (including mini gastric bypass and Roux-en-Y gastric bypass). The main questions it aims to answer are: Do stool tests show more signs of undigested food or carbohydrate malabsorption after gastric bypass compared to sleeve gastrectomy? Do signs of gut inflammation in stool (like fecal calprotectin) decrease after surgery, and does this relate to improvements in blood sugar and weight loss? Can simple stool test results at 6 months predict how much weight a person loses or how well their diabetes improves? Researchers will compare stool test results between the two surgery groups (sleeve gastrectomy vs. gastric bypass) to see if the type of surgery leads to different changes in gut health. Participants will: Provide a stool sample before surgery and again 6 months after surgery Provide a blood sample at the same time points to measure weight, blood sugar, and cholesterol Undergo their planned weight loss surgery as part of their regular medical care

Conditions

Morbid Obesity

Keywords

Bariatric Surgery; Stool Analysis; Fecal Calprotectin; Reducing Substances; Maldigestion; Gut Microbiota

Outcome Measures

Primary Outcomes (6)

• Change in Stool pH

  Change in stool pH measured by pH indicator strip from preoperative baseline to 6 months after surgery. Comparison will be made between Sleeve Gastrectomy (SG) and Gastric Bypass (MGB/RYGB) groups.

  At Baseline and at 6 months postoperatively

• Change in Fecal Calprotectin Level

  Change in fecal calprotectin concentration (μg/g) measured by ELISA from preoperative baseline to 6 months after surgery. Comparison will be made between Sleeve Gastrectomy (SG) and Gastric Bypass (MGB/RYGB) groups.

  At Baseline and at 6 months postoperatively

• Presence of Undigested Food Particles

  Presence or absence of undigested meat fibers and vegetable particles on microscopic examination at 6 months after surgery. Comparison of prevalence between Sleeve Gastrectomy (SG) and Gastric Bypass (MGB/RYGB) groups.

  At Baseline and at 6 months postoperatively

• Presence of Reducing Substances

  Presence or absence of reducing substances (indicating carbohydrate malabsorption) measured by Clinitest tablets at 6 months after surgery. Comparison of prevalence between Sleeve Gastrectomy (SG) and Gastric Bypass (MGB/RYGB) groups.

  At Baseline and at 6 months postoperatively

• Change in Stool White Blood Cell Count

  Change in white blood cell count (cells per high-power field) on microscopic examination from preoperative baseline to 6 months after surgery. Comparison will be made between Sleeve Gastrectomy (SG) and Gastric Bypass (MGB/RYGB) groups.

  At Baseline and at 6 months postoperatively

• Change in Stool Red Blood Cell Count

  Change in red blood cell count (cells per high-power field) on microscopic examination from preoperative baseline to 6 months after surgery. Presence of RBCs may indicate mucosal irritation at staple lines or altered barrier function. Comparison will be made between Sleeve Gastrectomy (SG) and Gastric Bypass (MGB/RYGB) groups.

  At Baseline and at 6 months postoperatively

Secondary Outcomes (18)

• Percentage Total Weight Loss (%TWL)

  6 months postoperatively

• Diabetes Remission Rate

  6 months postoperatively

• Change in Fasting Plasma Glucose

  At Baseline and at 6 months postoperatively

• Change in HbA1c

  At Baseline and at 6 months postoperatively

• Change in Lipid Profile

  At Baseline and at 6 months postoperatively

Study Arms (2)

Sleeve Gastrectomy (SG)

Patients undergoing primary laparoscopic sleeve gastrectomy as treatment for morbid obesity. This group serves as the restrictive procedure comparator.

Procedure: Laparoscopic Sleeve Gastrectomy

Gastric Bypass (MGB/RYGB)

Patients undergoing primary laparoscopic gastric bypass, including both Mini Gastric Bypass (MGB) and Roux-en-Y Gastric Bypass (RYGB), as treatment for morbid obesity. This group serves as the diversionary procedure comparator.

Procedure: Mini Gastric Bypass; Procedure: Roux-en-Y Gastric Bypass

Interventions

Laparoscopic Sleeve Gastrectomy PROCEDURE

Laparoscopic sleeve gastrectomy performed using a standard technique with a 36-Fr bougie, transecting the stomach starting 4-6 cm from the pylorus, excising the entire greater curvature and fundus. The staple line is inspected for hemostasis and leakage.

Sleeve Gastrectomy (SG)

Mini Gastric Bypass PROCEDURE

Laparoscopic mini gastric bypass performed using a standard technique with a long gastric tube created from the angle of His to the antrum, and a loop gastrojejunostomy with a biliopancreatic limb of 200 cm.

Gastric Bypass (MGB/RYGB)

Roux-en-Y Gastric Bypass PROCEDURE

Laparoscopic Roux-en-Y gastric bypass performed using a standard antecolic, antegastric technique. A small 30-mL gastric pouch is created. The biliopancreatic limb is 70-150 cm, and the alimentary (Roux) limb is 100-150 cm. Jejunojejunostomy is performed to restore continuity.

Gastric Bypass (MGB/RYGB)

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Patients with morbid obesity scheduled for primary bariatric surgery at Kasr Al-Ainy University Hospitals, Cairo, Egypt.

You may qualify if:

• Male and female patients aged 18 to 60 years
• Body Mass Index (BMI) ≥ 40 kg/m², OR BMI ≥ 35 kg/m² with at least one obesity-related comorbidity (type 2 diabetes, hypertension, dyslipidemia, osteoarthritis, obstructive sleep apnea)
• Patients scheduled for primary laparoscopic bariatric surgery (either SG or Gastric Bypass \[MGB or RYGB\]) at Kasr Al-Ainy University Hospitals
• Provision of written informed consent

You may not qualify if:

• Age \< 18 years or \> 60 years
• Previous bariatric surgery or major gastrointestinal surgery (gastric, intestinal, or colorectal resection)
• Chronic kidney disease (eGFR \< 60 mL/min/1.73m²) or previous renal transplant
• Chronic liver disease (cirrhosis, chronic hepatitis) or liver failure
• Chronic inflammatory bowel disease (Crohn's disease, ulcerative colitis), celiac disease, or chronic pancreatitis
• Active malignancy or history of chemotherapy/radiotherapy in the past 5 years
• Pregnancy or breastfeeding
• Chronic alcohol abuse or substance abuse
• Use of antibiotics, probiotics, or prebiotics within 4 weeks prior to stool sample collection (to avoid confounding effects on gut flora)
• Acute gastrointestinal infection at the time of sample collection

Sponsors & Collaborators

• Cairo University: lead

Study Sites (1)

Faculty of Medicine Cairo University

Cairo, Al-Manial Cairo, 11956, Egypt

RECRUITING

MeSH Terms

Conditions

Obesity, Morbid

Interventions

Gastric Bypass

Condition Hierarchy (Ancestors)

Obesity; Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Bariatric Surgery; Bariatrics; Obesity Management; Therapeutics; Gastroenterostomy; Anastomosis, Surgical; Surgical Procedures, Operative; Digestive System Surgical Procedures

Central Study Contacts

Ahmed Eid Aziz, Lecturer

CONTACT

+201127060844; Ahmed-eid@kasralainy.edu.eg

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Lecturer

Study Record Dates

• First Submitted: March 4, 2026
• First Posted: March 10, 2026
• Study Start: April 5, 2026
• Primary Completion (Estimated): November 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: May 18, 2026

Record last verified: 2026-05

Locations

EG (1)