Evaluation of Metabolic Parameters, Intestinal Permeability and Gastrointestinal Symptoms After Bariatric Surgery in Body Weight Management (METABAR)

June 8, 2026 updated by: Betül Gülşen, Toros University

Evaluation of Postoperative Metabolic Parameters, Intestinal Permeability and Gastrointestinal Symptoms in Body Weight Management After Laparoscopic Sleeve Gastrectomy

This study aims to evaluate the changes in metabolic parameters, intestinal permeability, and gastrointestinal symptoms in individuals who have undergone bariatric surgery (Laparoscopic Sleeve Gastrectomy - LSG) for obesity treatment.

Obesity is a chronic disease associated with serious health complications including type 2 diabetes, hypertension, cardiovascular disease, and metabolic disorders. Bariatric surgery is currently the most effective treatment method for morbid obesity. However, monitoring patients after surgery in terms of metabolic health, gut permeability, and gastrointestinal symptoms is crucial for long-term success.

In this study, 40 volunteers (aged 19-50) who have undergone LSG surgery within the last month will be followed for 6 months. At the beginning of the study and 6 months later, the following will be assessed:

  • Metabolic parameters: fasting blood glucose, total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL) cholesterol, and insulin levels
  • Intestinal permeability markers: zonulin, secretory immunoglobulin A (IgA), and lipopolysaccharide (LPS) levels
  • Gastrointestinal symptoms: assessed using the Gastrointestinal Symptom Rating Scale (GSRS)
  • Anthropometric measurements: body weight, height, waist and hip circumference, BMI
  • Nutritional intake: 3-day dietary records

The study will be conducted at Bursa Yıldırım Doruk Hospital, General Surgery Clinic. Results will contribute to understanding the relationship between bariatric surgery and gut health, potentially helping to prevent postoperative complications.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Obesity is defined by the World Health Organization (WHO) as abnormal or excessive fat accumulation that presents a risk to health. Bariatric surgery, particularly Laparoscopic Sleeve Gastrectomy (LSG), is considered the most effective long-term treatment for morbid obesity.

This prospective observational study will be conducted at Bursa Yıldırım Doruk Hospital with 40 volunteers who have undergone LSG within the last month. Participants will be evaluated at baseline (immediately after surgery) and at 6 months post-surgery.

Assessments include:

  1. Anthropometric Measurements: Body weight, height, waist and hip circumference will be measured. BMI and waist-to-hip ratio will be calculated according to WHO criteria.
  2. Biochemical Parameters: Fasting blood glucose, total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL) cholesterol, and insulin levels will be obtained from patient records. Zonulin, secretory immunoglobulin A (IgA), and lipopolysaccharide (LPS) levels will be analyzed using ELISA method (Biotek TS800) with commercial kits (RelAssay® Diagnostics, Ankara, Turkey) at Ankara Diagen Laboratory. Samples will be stored at -20°C until analysis.
  3. Gastrointestinal Symptom Rating Scale (GSRS): A validated 15-item scale assessing five dimensions: diarrhea, indigestion, constipation, abdominal pain, and reflux. Scores range from 1 (no discomfort) to 7 (very severe discomfort). Turkish validity and reliability was established by Turan and Asti (2011).
  4. Dietary Assessment: 3-day dietary records will be collected and analyzed using the Nutrition Information System (BeBIS) 8.2 software. Results will be evaluated according to the Turkish Dietary Guidelines 2022 (TUBER 2022).

Statistical analyses will be performed using the Statistical Package for the Social Sciences (SPSS) 22.0. Normal distribution will be assessed using Kolmogorov-Smirnov/Shapiro-Wilk tests. Results will be expressed as mean ± standard deviation for continuous variables and frequency/percentage for categorical variables.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Turkey (Türkiye)
    • Bursa
      • Bursa, Bursa, Turkey (Türkiye), 16310
        • Bursa Yıldırım Doruk Hospital
        • Principal Investigator:
          • Özlem ÖZPAK AKKUŞ, Assoc. Prof.
        • Sub-Investigator:
          • Doğukan Durak, Assoc. Prof.
        • Sub-Investigator:
          • Seher ŞEN, Asst. Prof.
        • Contact:
        • Contact:
        • Principal Investigator:
          • Betül GÜLŞEN, Assoc. Prof.
        • Sub-Investigator:
          • Tuğçe Nur Doganay Yıldırım, MSc, RD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adults with morbid obesity who underwent Laparoscopic Sleeve Gastrectomy (LSG) at Bursa Yıldırım Doruk Hospital General Surgery Clinic within the last month, meeting the inclusion criteria.

Description

Inclusion Criteria:

  • Underwent Laparoscopic Sleeve Gastrectomy (LSG) within the last 1 month
  • Aged between 19-50 years
  • BMI ≥40 kg/m² or BMI ≥35 kg/m² with obesity-related comorbidities
  • Signed informed consent form
  • Non-smoker and non-alcohol dependent

Exclusion Criteria:

  • Did not undergo or is not planned to undergo LSG
  • Outside the age range of 19-50 years
  • Did not sign the informed consent form
  • BMI <40 kg/m² or BMI <35 kg/m² without obesity-related comorbidities
  • Smoker or alcohol dependent
  • Has an inflammatory disease
  • Currently using probiotics, antibiotics, or fiber supplements
  • Has a psychiatric disorder

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
LSG Group
Adults aged 19-50 years who underwent Laparoscopic Sleeve Gastrectomy (LSG) within the last month at Bursa Yıldırım Doruk Hospital. Participants will be evaluated at baseline and 6 months after surgery for metabolic parameters, intestinal permeability markers, gastrointestinal symptoms, anthropometric measurements, and dietary intake.
Other: Clinical and Biochemical Assessment
Participants will undergo two assessment visits: at baseline (within 1 month post-surgery) and at 6-month follow-up. Each visit includes anthropometric measurements (body weight, height, waist and hip circumference, BMI), biochemical blood analysis (fasting glucose, lipid profile, insulin, zonulin, secretory IgA, LPS), gastrointestinal symptom evaluation via GSRS, and 3-day dietary records.
Other Names:
  • Anthropometric Measurement
  • Biochemical Blood Analysis
  • Gastrointestinal Symptom Rating Scale (GSRS)
  • 3-Day Dietary Record
  • Intestinal Permeability Assessment

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Change in Fasting Blood Glucose Concentration (mg/dL)
Time Frame: Baseline and 6 months
Change in serum fasting blood glucose levels after 12-hour fasting between baseline and 6-month follow-up.
Baseline and 6 months
Change in Total Cholesterol Concentration (mg/dL)
Time Frame: Baseline and 6 months
Change in serum total cholesterol levels after 12-hour fasting between baseline and 6-month follow-up.
Baseline and 6 months
Change in Triglyceride Concentration (mg/dL)
Time Frame: Baseline and 6 months
Change in serum triglyceride levels after 12-hour fasting between baseline and 6-month follow-up.
Baseline and 6 months
Change in HDL Cholesterol Concentration (mg/dL)
Time Frame: Baseline and 6 months
Change in serum high-density lipoprotein (HDL) cholesterol levels after 12-hour fasting between baseline and 6-month follow-up.
Baseline and 6 months
Change in LDL Cholesterol Concentration (mg/dL)
Time Frame: Baseline and 6 months
Change in serum low-density lipoprotein (LDL) cholesterol levels after 12-hour fasting between baseline and 6-month follow-up.
Baseline and 6 months
Change in VLDL Cholesterol Concentration (mg/dL)
Time Frame: Baseline and 6 months
Change in serum very low-density lipoprotein (VLDL) cholesterol levels after 12-hour fasting between baseline and 6-month follow-up.
Baseline and 6 months
Change in Fasting Insulin Concentration (µIU/mL)
Time Frame: Baseline and 6 months
Change in serum fasting insulin levels after 12-hour fasting between baseline and 6-month follow-up.
Baseline and 6 months
Change in Serum Zonulin Concentration (ng/mL)
Time Frame: Baseline and 6 months
Change in serum zonulin levels assessed by ELISA method between baseline and 6-month follow-up.
Baseline and 6 months
Change in Serum Secretory IgA Concentration (mg/dL)
Time Frame: Baseline and 6 months
Change in serum secretory IgA levels assessed by ELISA method between baseline and 6-month follow-up.
Baseline and 6 months
Change in Serum LPS Concentration (EU/mL)
Time Frame: Baseline and 6 months
Change in serum lipopolysaccharide (LPS) levels assessed by ELISA method between baseline and 6-month follow-up.
Baseline and 6 months
Change in Gastrointestinal Symptom Rating Scale (GSRS) Total Score (1-7)
Time Frame: Baseline and 6 months
Change in total score of the Gastrointestinal Symptom Rating Scale (GSRS) between baseline and 6-month follow-up. The scale consists of 15 items across 5 subscales; scores range from 1 to 7, with higher scores indicating more severe gastrointestinal symptoms.
Baseline and 6 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in Body Weight (kg)
Time Frame: Baseline and 6 months
Change in body weight between baseline and 6-month follow-up.
Baseline and 6 months
Change in Body Mass Index (kg/m²)
Time Frame: Baseline and 6 months
Change in BMI between baseline and 6-month follow-up. Weight and height will be combined to report BMI in kg/m².
Baseline and 6 months
Change in Waist Circumference (cm)
Time Frame: Baseline and 6 months
Change in waist circumference between baseline and 6-month follow-up.
Baseline and 6 months
Change in Hip Circumference (cm)
Time Frame: Baseline and 6 months
Change in hip circumference between baseline and 6-month follow-up.
Baseline and 6 months
Change in Waist-to-Hip Ratio
Time Frame: Baseline and 6 months
Change in waist-to-hip ratio between baseline and 6-month follow-up. Waist and hip circumference measurements will be combined to calculate the waist-to-hip ratio.
Baseline and 6 months
Change in Daily Energy Intake (kcal/day)
Time Frame: Baseline and 6 months
Change in daily energy intake assessed by 3-day dietary intake records between baseline and 6-month follow-up. Data will be analyzed using BeBIS 8.2 software.
Baseline and 6 months
Change in Daily Protein Intake (g/day)
Time Frame: Baseline and 6 months
Change in daily protein intake assessed by 3-day dietary intake records between baseline and 6-month follow-up. Data will be analyzed using BeBIS 8.2 software.
Baseline and 6 months
Change in Daily Carbohydrate Intake (g/day)
Time Frame: Baseline and 6 months
Change in daily carbohydrate intake assessed by 3-day dietary intake records between baseline and 6-month follow-up. Data will be analyzed using BeBIS 8.2 software.
Baseline and 6 months
Change in Daily Fat Intake (g/day)
Time Frame: Baseline and 6 months
Change in daily fat intake assessed by 3-day dietary intake records between baseline and 6-month follow-up. Data will be analyzed using BeBIS 8.2 software.
Baseline and 6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Toros University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Betül GÜLŞEN, Assoc. Prof., Toros University
  • Study Chair: Özlem ÖZPAK AKKUŞ, Assoc. Prof., Toros University
  • Study Director: Doğukan DURAK, Assoc. Prof., Bursa Yıldırım Doruk Hospital, General Surgery Clinic

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
February 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 20, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 8, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 11, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 11, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 8, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • BCKLY-BGP-2026

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared due to ethical considerations and participant confidentiality. Data will be stored securely and used only for the purposes of this study in accordance with Turkish Personal Data Protection Law (KVKK) and the ethical approval pending from Toros University Faculty of Health Sciences Non-Interventional Clinical Research Ethics Committee.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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