Condition category
Nutritional, Metabolic, Endocrine
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Obesity is a growing problem worldwide. In Spain, around 22.9% of the population is overweight, with 1.8% being dangerously so (morbid obesity). It is well known that obesity can lead to a number of other serious health conditions such as cancer, cardiovascular disease (disease of the heart and blood vessels) and diabetes. By losing excess weight, it is thought that people can dramatically reduce their risk of developing these conditions. Weight loss surgery, also called bariatric surgery, is a drastic measure used to help people who are dangerously overweight and unable to lose weight naturally (through diet and exercise). There are a number of different types of bariatric surgery; however they all work by limiting the amount a person can eat or reducing the number of calories that are absorbed from food. Recent studies have shown that when a person undergoes bariatric surgery, the amounts of different hormones involved in digestion and regulating fat storage change. The specific changes are also thought to be different depending on what type of bariatric surgery is used. This study will look at three different bariatic surgery procedures: gastric bypass surgery (where the stomach is stapled, making it smaller so less food can be eaten), sleeve gastrectomy surgery (where part of the stomach is removed, making the overall size of the stomach smaller) and a procedure called biliopancreatic diversion with duodenal switch (where a large part of the stomach is removed and what remains is connected to the final segment of the small intestine, so food in the intestine has less time to be absorbed). The aim of this study is to compare levels of hormones after eating in adult patients who have had one of these three bariatric surgery procedures, and compare these levels to those of healthy adults with normal weights.

Who can participate?
Adults who have been morbidly obese for at least 5 years and are having bariatric surgery, as well as healthy adults of the same age with a normal weight.

What does the study involve?
At the start of the study, 50 participants due to have bariatric surgery (gastric bypass surgery, sleeve gastrectomy surgery or biliopancreatic diversion with duodenal switch) and 20 healthy participants of a normal weight attend a study visit. At this visit, they are weighted and measured and have a series of blood tests before and 30, 60, 90 and 120 minutes after eating a standard meal so that their hormone levels can be measured. The hormone test is then repeated one year later. For the obese patients, weight is measured at these study visits and again 3 and 5 years after surgery.

What are the possible benefits and risks of participating?
There are no direct benefits or risks to participants taking part in the study.

Where is the study run from?
San Carlos Clinical Hospital (Spain)

When is the study starting and how long is it expected to run for?
February 2008 to May 2015

Who is funding the study?
1. Biomedical Research foundation of Mutua Madrileña (Spain)
2. Metabolic Studies Foundation, Hospial Clinico San Carlos (Spain)
3. Research in Metabolic and Nutrition Foundation (Spain)

Who is the main contact?
Mrs Patricia Martin

Trial website

Contact information



Primary contact

Mrs Patricia Martin


Contact details

Servicio de Endocrinologia y Nutrición
Hospital Universitario la Paz
Paseo de la Castellana 261

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Changes in gastrointestinal hormones and its relation with weight loss after gastric bypass, biliopancreatic deviation with duodenal swicht and sleeve gastrectomy: An observational study


Study hypothesis

The aim of this study is to find out whether the physiological hormonal response after a meal test is different in obese and normal weight patients, and whether bariatric surgery can elicit changes in hormonal responses.

Ethics approval

Ethics Committee of the Hospital Clínico San Carlos, 24/02/2003, ref: B-03/061

Study design

Prospective single-centre case-control study

Primary study design


Secondary study design

Case-control study

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet.


Morbid obesity


Morbidity obese patients who are having Roux-en-Y gastric bypass, biliopancreatic deviations with duodenal switch or sleeve gastrectomy are included in the study.

Obese and control group have anthropometric and hormonal measurements taken at baseline and 1 year after surgery. At each visit, participants have a blood sample taken, which is repeated 0, 60, 90 and 120 minutes after ingestion of a standard test meal.

Obese patients are asked to attend two additional study visits 3 and 5 years after surgery for weight control.

Intervention type



Drug names

Primary outcome measures

Hormonal response after meal test is measured from blood samples taken at baseline, 30, 60, 90 and 120 minutes after ingestion of a standard test meal, at baseline and one year post surgery.

Secondary outcome measures

Weight loss and the height was measured using an electric scale (SECA®) at baseline, 1, 3 and 5 years.

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

Obese participant inclusion criteria:
1. Aged between 18 and 65 years
2. BMI ≥ 40 kg/m2 or ≥ 35 kg/m2 with associated major comorbidities likely to improve after weight loss
3. That morbid obesity is set for at least 5 years.
4. Continuing failures to properly supervised conservative treatments
5. Ability to understand the mechanisms by which weight is lost with surgery and understand that good results are not always achieved
6. Understand that the goal of surgery is not reach the ideal weight
7. Commitment to adhere to the rules of follow-up after surgery
8. Informed consent after receiving all the (oral and written) information

Control participant inclusion criteria:
1. Aged between 18 and 65 years
2. No diabetes mellitus (basal glucose <126 mg/dl and/or Hba1c < 6.5%)
3. BMI <30 and >18 kg/m2
4. No drugs or alcohol abuse.
5. No mayor psychiatric disorders (schizophrenia, psychosis) no eating disorders( anorexia nervosa, bulimia)
6. Informed consent after receiving all the (oral and written) information

Participant type


Age group




Target number of participants

A total of 23 patients underwent GB surgery, 17 BPD-DS and 10 SG with a control group of 20 healthy and normal weight volunteers

Participant exclusion criteria

1. Endocrine disorders that can cause morbid obesity.
2. Psychological instability including abuse of alcohol or drugs, major psychiatric disorders (schizophrenia, psychosis), mental retardation, eating disorders (bulimia nervosa, binge eating)
3. Pregnancy

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Clinico San Carlos Hospital (Hospital Clínico San Carlos)
Calle del Prof Martín Lagos

Sponsor information


San Carlos Clinical Hospital (Hospital Clínico San Carlos)

Sponsor details

Endocrinology and Nutrition Service (Servicio de Endocrinologia y Nutrición)
Calle del Prof Martín Lagos

Sponsor type

Hospital/treatment centre



Funder type

Not defined

Funder name

Biomedical Research foundation of Mutua Madrileña

Alternative name(s)

Funding Body Type

Funding Body Subtype


Funder name

Metabolic Studies Foundation, Hospial Clinico San Carlos

Alternative name(s)

Funding Body Type

Funding Body Subtype


Funder name

Research in Metabolic and Nutrition Foundation (FINUMET)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

1. Presented as Patricia Martin's PhD project
2. Planned publication in peer reviewed journals

Intention to publish date


Participant level data

Not expected to be available

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes