Kidney Function Indexed Extracellular Volume Before and After Obesity Surgery

June 15, 2026 updated by: Centre Hospitalier Universitaire de Nice

Measurement of Kidney Function Indexed Extracellular Volume Before and After Obesity Surgery in Kidney Patients With Severe Obesity or Massive

Obesity promotes chronic kidney disease and is accelerating its shift to the stage of renal replacement. Bariatric surgery is a treatment for severe or morbid obesity whose renal benefit is currently unknown. The glomerular filtration rate (GFR) is the best parameter to define the kidney function. It can be estimated using formulas by assaying endogenous markers (creatinine, cystatin C) or measured with an exogenous tracer glomerular filtration (51 Cr-EDTA).

Bariatric surgery alters the production of endogenous markers and the extracellular volume (VEC) with 2 important consequences on the assessment of GFR: the formula to estimate GFR is not possible to compare renal function before and after surgery because of the variation in production of endogenous glomerular filtration markers in the same subject; decreasing VEC predicted decreased GFR after surgery, since these parameters are in part proportional to each other.

Our working hypothesis is that bariatric surgery protects the kidneys of patients with chronic kidney disease. To demonstrate this, investigators propose to compare the ratio DFG / VEC before and after gastric bypass.

Goals The main objective is to measure the effect of gastric bypass on the report DFG / VEC. Secondary objectives are to assess the effect of gastric bypass on the albumin / urine creatinine and evaluate the performance of the main GFR estimating formulas in people with severe or morbid obesity.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

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.

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.
Interventional

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.
14

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

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 Locations

  • France
      • Nice, France
        • Chu De Nice

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

18 years to 70 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Topic GFR estimated by having the simplified formula of MDRD <60 ml / min / 1.73 m²
  • Topic with BMI ≥ 40 kg / m², or ≥ 35 kg / m²
  • Subject having at least one comorbidity could be improved after surgery after failure of medical treatment: hypertension , OSAHS and other severe respiratory disorders, severe metabolic disorders, particularly type 2 diabetes , debilitating musculoskeletal diseases, steatohepatitis nonalcoholic .
  • Topic who signed the informed consent
  • Topic affiliated to the social security
  • Male or female Topics
  • Elderly 18 to 70 inclusive

Exclusion Criteria:

  • Non- Caucasian person because the necessary correction factors and not always available for the formula to estimate GFR ( Cockcroft , Salazar and Corcoran ) .
  • No major under guardianship
  • Nobody hospitalized without his consent and not protected by law
  • Private person of liberty
  • Pregnant Woman, knowing that a pregnancy test will be performed for women of childbearing age . Results will be communicated to the patient by a doctor of his choice.
  • Rapidly progressive glomerulonephritis
  • Nephrotic proteinuria ranking

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

  • Primary Purpose: Other
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
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.
Other: DFG mesure
Measure the effect of gastric bypass on the report DFG / VEC
Other: DFG mesure
Measure the effect of gastric bypass on the report DFG / VEC.

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
Ratio DFG / VEC
Time Frame: Month 12
Average ratio DFG / VEC before and one year after gastric bypass
Month 12

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
Albumin / urine creatinine
Time Frame: Month 12
Month 12
GFR estimation formula
Time Frame: Month 12
GFR using the Cockcroft formulas , Salazar and Corcoran , simplified MDRD and CKD -EPI . Each of GFR estimation formula , we calculate the mean bias by the difference between the estimated value and the measured value and the percentage of patients with the value obtained by estimation is between -25 % and + 25 % in value measured ( awerage Within 50 or AW50 )
Month 12

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.
Centre Hospitalier Universitaire de Nice

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 (Actual)

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.
December 30, 2015

Primary Completion (Actual)

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.
March 20, 2018

Study Completion (Actual)

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.
March 5, 2020

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 12, 2015

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.
July 8, 2016

First Posted (Estimated)

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.
July 13, 2016

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 16, 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 15, 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.
July 1, 2016

More Information

Terms related to this study

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.
  • 14-AOI-09

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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