Obesity & OverweightNCT07345429
One-Year Outcomes After Conversion Bariatric Surgery
An observational study of Obesity & Overweight and Bariatric Surgery, run by Medipol University at 1 site in Turkey (Türkiye).
Trial summary
Obesity is a growing global public health problem, and bariatric surgery is currently the most effective treatment for achieving sustained weight loss and improving obesity-related comorbidities. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Obesity & Overweight, Bariatric Surgery, Revisional Bariatric Surgery
- How many people
- 14 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 12 Nov 2024to 21 Feb 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Adult patients aged 18-65 years who had previously undergone bariatric surgery and subsequently received conversion bariatric surgery due to suboptimal clinical response, defined as suboptimal weight loss or recurrent weight gain. Participants are followed in routine clinical practice and evaluated preoperatively and at postoperative 1 year for anthropometric, biochemical, nutritional, and physical activity outcomes.
Who may be able to join
- Adults aged 18-45 years
- Previously underwent bariatric surgery
- Subsequently underwent conversion bariatric surgery due to suboptimal clinical response
- Suboptimal clinical response defined as either:
- Suboptimal Clinical Response (SCR): maximum total weight loss (TWL%) of <20% within 18 months after metabolic and bariatric surgery
- Recurrent Weight Gain (RWG): regaining >30% of initial postoperative weight loss after achieving initial weight reduction
Who cannot join
- Pregnancy or lactation
- Presence of acute illness or infection
- Comorbid conditions that could limit treatment efficacy or compromise safety
- Participation in professional athletic activity
Trial locations and contacts
1 site in 1 country.
About this study
Official title: ONE-YEAR OUTCOMES OF ANTHROPOMETRIC, BIOCHEMICAL, AND NUTRITIONAL PARAMETERS AFTER CONVERSION BARIATRIC SURGERY
Obesity is a growing global public health problem, and bariatric surgery is currently the most effective treatment for achieving sustained weight loss and improving obesity-related comorbidities. However, a subset of patients experience inadequate weight loss or weight regain following primary bariatric surgery, which may lead to the recurrence of metabolic complications and reduced quality of life. In such cases, conversion bariatric surgery, defined as the surgical conversion from one bariatric procedure to another, is considered an important therapeutic option. Despite the increasing number of conversion procedures, comprehensive longitudinal data evaluating anthropometric, biochemical, and nutritional outcomes after conversion bariatric surgery remain limited.
This study aims to prospectively evaluate individuals undergoing conversion bariatric surgery due to weight regain following primary bariatric surgery. Anthropometric measurements, biochemical parameters, and nutritional status will be assessed preoperatively and at 1 year after surgery. By evaluating weight loss outcomes together with metabolic and nutritional changes, this study seeks to provide clinically relevant evidence to guide postoperative follow-up strategies, optimize nutritional management, and support multidisciplinary care in patients undergoing conversion bariatric surgery.
- Keywords
- conversion bariatric surgery, obesity, nutritional assessment, weight regain, metabolic outcomes, anthropometric measurements
- Medical subject headings
- Obesity, Overweight
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Conversion Bariatric Surgery | This cohort includes patients who previously underwent conversion bariatric surgery as part of routine clinical care and were followed observationally. Anthropometric measurements, biochemical parameters, and nutritional status were assessed at the preoperative period and postoperative month 12 (1 year). |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Body Composition Parameters
Body composition parameters including fat mass, fat percentage, fat-free mass, fat-free mass percentage, skeletal muscle mass, muscle percentage, and extracellular water to total body water ratio assessed using multi-frequency bioelectrical impedance analysis (BIA).
Measured: Preoperative baseline and postoperative 1 year
Change in Body Weight
Change in body weight (kg) measured using a digital scale with participants wearing light clothing and no shoes.
Measured: Preoperative baseline and postoperative 1 year
Change in Body Mass Index (BMI)
Change in body mass index (kg/m²) calculated from measured body weight and height.
Measured: Preoperative baseline and postoperative 1 year
Percentage of Total Weight Loss
Percentage of total weight loss calculated as [(preoperative weight - postoperative weight) / preoperative weight] × 100.
Measured: postoperative 1 year
Percentage of Excess Weight Loss
Percentage of excess weight loss calculated as [(preoperative weight - postoperative weight) / (preoperative weight - ideal body weight)] × 100, with ideal body weight defined as a BMI of 25 kg/m².
Measured: postoperative 1 year
Change in Waist Circumference
Waist circumference (cm) measured in the standing position using a non-elastic measuring tape at the midpoint between the lowest rib and the iliac crest.
Measured: Preoperative baseline and postoperative 1 year
Change in Hip Circumference
Hip circumference (cm) measured in the standing position at the point of maximum protrusion of the gluteal muscles using a non-elastic measuring tape.
Measured: Preoperative baseline and postoperative 1 year
Change in Body Fat Percentage (%)
Body fat percentage measured using multi-frequency bioelectrical impedance analysis (BIA).
Measured: Preoperative baseline and postoperative 1 year
Change in Fat-Free Mass (kg)
Fat-free mass measured using multi-frequency bioelectrical impedance analysis (BIA).
Measured: Preoperative baseline and postoperative 1 year
Change in Skeletal Muscle Mass (kg)
Skeletal muscle mass measured using multi-frequency bioelectrical impedance analysis (BIA).
Measured: Preoperative baseline and postoperative 1 year
Secondary outcomes (14)
Change in Fasting Plasma Glucose
Changes in fasting plasma glucose levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Change in Alanine Aminotransferase (ALT)
Changes in alanine aminotransferase (ALT) levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Change in Hematological Parameters
Changes in hemoglobin and hematocrit levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Change in Iron Status Parameters
Changes in serum ferritin, serum iron, and total iron-binding capacity levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Change in Micronutrient and Electrolyte Levels
Changes in serum vitamin B12, folic acid, magnesium, total calcium, sodium, and potassium levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Change in Fasting Insulin
Changes in fasting insulin levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Change in Glycated Hemoglobin (HbA1c)
Changes in glycated hemoglobin (HbA1c) levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Change in Total Cholesterol
Changes in total cholesterol levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Change in LDL Cholesterol
Changes in low-density lipoprotein (LDL) cholesterol levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Change in HDL Cholesterol
Changes in high-density lipoprotein (HDL) cholesterol levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Change in Triglyceride Levels
Changes in triglyceride levels measured from venous blood samples
Measured: Preoperative baseline and postoperative 1 year
Change in Aspartate Aminotransferase (AST)
Changes in aspartate aminotransferase (AST) levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Change in Urea Levels
Changes in serum urea levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Change in Uric Acid Levels
Changes in serum uric acid levels measured from venous blood samples.
Measured: Preoperative baseline and postoperative 1 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Jan 2026
- Study start12 Nov 2024
- Primary completion10 Jan 2026
- Study completion21 Feb 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Obesity & OverweightStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 14 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Medipol University
- Sponsor type
- University, hospital or other
- Collaborators
- Mudanya University
- Responsible party
- Principal investigator, Seher Şen, Mudanya University
- Investigators
- Seher Şen, Assistant Professor, Principal investigator, Mudanya University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07345429
- Sponsor's protocol ID
- MUDU-SBE-SS-01
- Status last verified
- Feb 2026
- First submitted
- 17 Dec 2025
- Last updated
- 3 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared due to the need to protect patient privacy and confidentiality.
Study at a glance
From the registry record, last updated by the sponsor on 3 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- ONE-YEAR OUTCOMES OF ANTHROPOMETRIC, BIOCHEMICAL, AND NUTRITIONAL PARAMETERS AFTER CONVERSION BARIATRIC SURGERY
- ClinicalTrials.gov ID
- NCT07345429
- Acronym / sponsor ID
- MUDU-SBE-SS-01
- Keywords
- conversion bariatric surgery, obesity, nutritional assessment, weight regain, metabolic outcomes, anthropometric measurements
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 14 participants (estimated)
- Lead sponsor
- Medipol UniversityUniversity, hospital or other
- Collaborators
- Mudanya University
- Study start
- 12 Nov 2024 (actual)
- Primary completion
- 10 Jan 2026 (actual)
- Study completion
- 21 Feb 2026 (estimated)
- First posted
- 15 Jan 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Obesity is a growing global public health problem, and bariatric surgery is currently the most effective treatment for achieving sustained weight loss and improving obesity-related comorbidities. However, a subset of patients experience inadequate weight loss or weight regain following primary bariatric surgery, which may lead to the recurrence of metabolic complications and reduced quality of life. In such cases, conversion bariatric surgery, defined as the surgical conversion from one bariatric procedure to another, is considered an important therapeutic option. Despite the increasing number of conversion procedures, comprehensive longitudinal data evaluating anthropometric, biochemical, and nutritional outcomes after conversion bariatric surgery remain limited.
This study aims to prospectively evaluate individuals undergoing conversion bariatric surgery due to weight regain following primary bariatric surgery. Anthropometric measurements, biochemical parameters, and nutritional status will be assessed preoperatively and at 1 year after surgery. By evaluating weight loss outcomes together with metabolic and nutritional changes, this study seeks to provide clinically relevant evidence to guide postoperative follow-up strategies, optimize nutritional management, and support multidisciplinary care in patients undergoing conversion bariatric surgery.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Conversion Bariatric Surgery | – | –This cohort includes patients who previously underwent conversion bariatric surgery as part of routine clinical care and were followed observationally. Anthropometric measurements, biochemical parameters, and nutritional status were assessed at the preoperative period and postoperative month 12 (1 year). |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Adult patients aged 18-65 years who had previously undergone bariatric surgery and subsequently received conversion bariatric surgery due to suboptimal clinical response, defined as suboptimal weight loss or recurrent weight gain. Participants are followed in routine clinical practice and evaluated preoperatively and at postoperative 1 year for anthropometric, biochemical, nutritional, and physical activity outcomes.
Key inclusion criteria (6 listed)
- Adults aged 18-45 years
- Previously underwent bariatric surgery
- Subsequently underwent conversion bariatric surgery due to suboptimal clinical response
- Suboptimal Clinical Response (SCR): maximum total weight loss (TWL%) of <20% within 18 months after metabolic and bariatric surgery
- Recurrent Weight Gain (RWG): regaining >30% of initial postoperative weight loss after achieving initial weight reduction
Key exclusion criteria (4 listed)
- Pregnancy or lactation
- Presence of acute illness or infection
- Comorbid conditions that could limit treatment efficacy or compromise safety
- Participation in professional athletic activity
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Change in Body Composition Parameters
Time frame: Preoperative baseline and postoperative 1 year
Body composition parameters including fat mass, fat percentage, fat-free mass, fat-free mass percentage, skeletal muscle mass, muscle percentage, and extracellular water to total body water ratio assessed using multi-frequency bioelectrical impedance analysis (BIA).
Change in Body Weight
Time frame: Preoperative baseline and postoperative 1 year
Change in body weight (kg) measured using a digital scale with participants wearing light clothing and no shoes.
Change in Body Mass Index (BMI)
Time frame: Preoperative baseline and postoperative 1 year
Change in body mass index (kg/m²) calculated from measured body weight and height.
Percentage of Total Weight Loss
Time frame: postoperative 1 year
Percentage of total weight loss calculated as [(preoperative weight - postoperative weight) / preoperative weight] × 100.
Percentage of Excess Weight Loss
Time frame: postoperative 1 year
Percentage of excess weight loss calculated as [(preoperative weight - postoperative weight) / (preoperative weight - ideal body weight)] × 100, with ideal body weight defined as a BMI of 25 kg/m².
Change in Waist Circumference
Time frame: Preoperative baseline and postoperative 1 year
Waist circumference (cm) measured in the standing position using a non-elastic measuring tape at the midpoint between the lowest rib and the iliac crest.
Change in Hip Circumference
Time frame: Preoperative baseline and postoperative 1 year
Hip circumference (cm) measured in the standing position at the point of maximum protrusion of the gluteal muscles using a non-elastic measuring tape.
Change in Body Fat Percentage (%)
Time frame: Preoperative baseline and postoperative 1 year
Body fat percentage measured using multi-frequency bioelectrical impedance analysis (BIA).
Change in Fat-Free Mass (kg)
Time frame: Preoperative baseline and postoperative 1 year
Fat-free mass measured using multi-frequency bioelectrical impedance analysis (BIA).
Change in Skeletal Muscle Mass (kg)
Time frame: Preoperative baseline and postoperative 1 year
Skeletal muscle mass measured using multi-frequency bioelectrical impedance analysis (BIA).
14 secondary outcomes
Change in Fasting Plasma Glucose
Time frame: Preoperative baseline and postoperative 1 year
Change in Alanine Aminotransferase (ALT)
Time frame: Preoperative baseline and postoperative 1 year
Change in Hematological Parameters
Time frame: Preoperative baseline and postoperative 1 year
Change in Iron Status Parameters
Time frame: Preoperative baseline and postoperative 1 year
Change in Micronutrient and Electrolyte Levels
Time frame: Preoperative baseline and postoperative 1 year
Change in Fasting Insulin
Time frame: Preoperative baseline and postoperative 1 year
Change in Glycated Hemoglobin (HbA1c)
Time frame: Preoperative baseline and postoperative 1 year
Change in Total Cholesterol
Time frame: Preoperative baseline and postoperative 1 year
Change in LDL Cholesterol
Time frame: Preoperative baseline and postoperative 1 year
Change in HDL Cholesterol
Time frame: Preoperative baseline and postoperative 1 year
Change in Triglyceride Levels
Time frame: Preoperative baseline and postoperative 1 year
Change in Aspartate Aminotransferase (AST)
Time frame: Preoperative baseline and postoperative 1 year
Change in Urea Levels
Time frame: Preoperative baseline and postoperative 1 year
Change in Uric Acid Levels
Time frame: Preoperative baseline and postoperative 1 year
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Feb 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be shared due to the need to protect patient privacy and confidentiality.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Seher Şen, Assistant Professor principal investigator
Mudanya University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Obesity & Overweight and Bariatric Surgery, run by Medipol University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 3 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Body Composition Parameters (time frame: Preoperative baseline and postoperative 1 year). The study lists 10 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Feb 2026.