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NCT Number: NCT02872493

Small Bowel Length and Bariatric Surgery Outcomes

The purpose of this study is to determine whether or not the total length of small intestine effects outcomes after bariatric surgery in a cohort of patients preoperatively and up to ten years postoperatively. Roux-en-Y gastric bypass and vertical sleeve gastrectomy will be the surgical groups in this study. We aim to determine if bowel length has a significant effect on long term weight loss or other nutritional deficiencies in this bariatric cohort.

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Key information

Conditions

Malnutrition Body Weight Body Weight Changes Micronutrient Deficiency Nutrition Disorders Nutritional and Metabolic Diseases Obesity Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms Weight Loss

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Vanderbilt University Medical Center

Nashville, Tennessee, 37232, United States

About this study

Bariatric surgery (also known as "weight loss surgery") is the most effective treatment for obesity as well as a number of other obesity-related conditions, including type 2 diabetes, hypertension, and hypercholesterolemia. Interestingly, not all patients respond with significant weight loss following surgery and some patients even lack much weight loss at all over the long-term. Even though variability in treatment response is observed in a variety of diseases, the biological basis for this variability in weight loss after bariatric surgery is poorly understood. Recent data from our group as well as others, however, suggest that differences in the total length of the small intestine may significantly contribute to these differences in weight loss over time. For example, Roux-en-Y gastric bypass is thought to exert its weight loss effect because of a bypass of small intestine that causes a degree of nutrient malabsorption. The bypassed small intestine (<100cm) is near the proximal end of the intestines closest to the stomach. Hypothetically, an individual with the greater total small intestine length may not benefit as much from the bypass as someone who has a much shorter length of total small intestine. Whether or not this hypothetical relationship is true remains unknown, but a recent study demonstrated that small intestine length does differ significantly between individuals with lengths ranging from 300cm to >1200cm. The total length of small intestine is not routinely measured during any bariatric procedure, as the lengths of the bypass limbs are determined from the portion of the intestines closest to the stomach. The purpose of this study is to determine whether the amount of total small intestine significantly affects weight loss in patients undergoing bariatric surgery - both the Roux-en-Y gastric bypass (RYGB) or the Vertical Sleeve Gastrectomy (VSG). If there is a significant effect of total small intestine length on long-term weight loss in bariatric patients, then it would justify the conduct of a further study to determine whether or not these operations should be performed differently in individuals to account for the differences in small intestine length. This is an observational study that will be looking at body weight (primary endpoint) and other nutritional endpoints (other pre-specified outcome measure) over time up to ten years in this patient cohort. The body weight measurements and any laboratory data will be collected that are part of the routine clinical care of these patients.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients undergoing laparoscopic bariatric surgery, either vertical sleeve gastrectomy or Roux-en-Y gastric bypass
  • Able to give informed consent

Exclusion criteria

  • Prior small intestine resection.
  • Inability to safely obtain total small intestinal length measurements in the operating room.
  • Any small bowel tethering due to intestinal adhesions identified in the operating room.

Treatment and study plan

Small bowel length measurement

Procedure

The total length of the small bowel with be measured at the time of the bariatric surgical operation.

Primary outcomes

  1. Body Weight

    Time frame: Up to 10 years postoperatively as measured for routine clinical care

    Body weight will be measured preoperatively (within 30 days of the operation) as the baseline body weight, then postoperatively up to ten years from the time of initial surgery. Measurements will be made per routine clinical care and not solely for research purposes. Exact time points before and after surgery that body weight will be measured, except for the day of surgery, will differ between patients in the study.

    Change in body weight over time will be measured annually, adjusted for baseline body weight at the time of surgery.

    Regression will be used to test for a significant interaction of "total bowel length" and "body weight" over time in the patient cohorts (RYGB vs. VSG) - this is our primary outcome measurement. We are examining whether there is a significant interaction between any change in body weight over time and the small bowel length in the patient cohorts.

Other outcomes

  1. Vitamin A

    Time frame: Up to 10 years postoperatively

    Other pre-specified outcomes will be analyzed annually, adjusted for baseline measurements. Similar to the primary endpoint, data will be analyzed as continuous variables and tested for an interaction between total bowel length and the nutritional variable of interest. These other nutritional outcomes will vary depending on the clinical course of the individual patients in this observational study. Thus, time points that patients will have these variables measured will not be exactly the same across patients and will depend on the clinical care of the individual patient.

  2. Vitamin D

    Time frame: Up to 10 years postoperatively

    Other pre-specified outcomes will be analyzed annually, adjusted for baseline measurements. Similar to the primary endpoint, data will be analyzed as continuous variables and tested for an interaction between total bowel length and the nutritional variable of interest. These other nutritional outcomes will vary depending on the clinical course of the individual patients in this observational study. Thus, time points that patients will have these variables measured will not be exactly the same across patients and will depend on the clinical care of the individual patient.

  3. Vitamin E

    Time frame: Up to 10 years postoperatively

    Other pre-specified outcomes will be analyzed annually, adjusted for baseline measurements. Similar to the primary endpoint, data will be analyzed as continuous variables and tested for an interaction between total bowel length and the nutritional variable of interest. These other nutritional outcomes will vary depending on the clinical course of the individual patients in this observational study. Thus, time points that patients will have these variables measured will not be exactly the same across patients and will depend on the clinical care of the individual patient.

  4. Vitamin B1

    Time frame: Up to 10 years postoperatively

    Other pre-specified outcomes will be analyzed annually, adjusted for baseline measurements. Similar to the primary endpoint, data will be analyzed as continuous variables and tested for an interaction between total bowel length and the nutritional variable of interest. These other nutritional outcomes will vary depending on the clinical course of the individual patients in this observational study. Thus, time points that patients will have these variables measured will not be exactly the same across patients and will depend on the clinical care of the individual patient.

  5. Vitamin B2

    Time frame: Up to 10 years postoperatively

    Other pre-specified outcomes will be analyzed annually, adjusted for baseline measurements. Similar to the primary endpoint, data will be analyzed as continuous variables and tested for an interaction between total bowel length and the nutritional variable of interest. These other nutritional outcomes will vary depending on the clinical course of the individual patients in this observational study. Thus, time points that patients will have these variables measured will not be exactly the same across patients and will depend on the clinical care of the individual patient.

  6. Vitamin B6

    Time frame: Up to 10 years postoperatively

    Other pre-specified outcomes will be analyzed annually, adjusted for baseline measurements. Similar to the primary endpoint, data will be analyzed as continuous variables and tested for an interaction between total bowel length and the nutritional variable of interest. These other nutritional outcomes will vary depending on the clinical course of the individual patients in this observational study. Thus, time points that patients will have these variables measured will not be exactly the same across patients and will depend on the clinical care of the individual patient.

  7. Vitamin B12

    Time frame: Up to 10 years postoperatively

    Other pre-specified outcomes will be analyzed annually, adjusted for baseline measurements. Similar to the primary endpoint, data will be analyzed as continuous variables and tested for an interaction between total bowel length and the nutritional variable of interest. These other nutritional outcomes will vary depending on the clinical course of the individual patients in this observational study. Thus, time points that patients will have these variables measured will not be exactly the same across patients and will depend on the clinical care of the individual patient.

  8. Iron

    Time frame: Up to 10 years postoperatively

    Other pre-specified outcomes will be analyzed annually, adjusted for baseline measurements. Similar to the primary endpoint, data will be analyzed as continuous variables and tested for an interaction between total bowel length and the nutritional variable of interest. These other nutritional outcomes will vary depending on the clinical course of the individual patients in this observational study. Thus, time points that patients will have these variables measured will not be exactly the same across patients and will depend on the clinical care of the individual patient.

  9. Parathyroid Hormone

    Time frame: Up to 10 years postoperatively

    Other pre-specified outcomes will be analyzed annually, adjusted for baseline measurements. Similar to the primary endpoint, data will be analyzed as continuous variables and tested for an interaction between total bowel length and the nutritional variable of interest. These other nutritional outcomes will vary depending on the clinical course of the individual patients in this observational study. Thus, time points that patients will have these variables measured will not be exactly the same across patients and will depend on the clinical care of the individual patient.

  10. Total Iron Binding Capacity

    Time frame: Up to 10 years postoperatively

    Other pre-specified outcomes will be analyzed annually, adjusted for baseline measurements. Similar to the primary endpoint, data will be analyzed as continuous variables and tested for an interaction between total bowel length and the nutritional variable of interest. These other nutritional outcomes will vary depending on the clinical course of the individual patients in this observational study. Thus, time points that patients will have these variables measured will not be exactly the same across patients and will depend on the clinical care of the individual patient.

  11. Ferritin

    Time frame: Up to 10 years postoperatively

    Other pre-specified outcomes will be analyzed annually, adjusted for baseline measurements. Similar to the primary endpoint, data will be analyzed as continuous variables and tested for an interaction between total bowel length and the nutritional variable of interest. These other nutritional outcomes will vary depending on the clinical course of the individual patients in this observational study. Thus, time points that patients will have these variables measured will not be exactly the same across patients and will depend on the clinical care of the individual patient.

Sponsors and collaborators

Lead sponsor

Vanderbilt University Medical Center

Other

Registry information

Official study title

Observational Study of the Effect of Small Intestine Length on Bariatric Surgical Patient Outcomes

Important dates

Study start
2016
Primary completion
2025
Study completion
2025
First posted
Aug 19, 2016
Registry last updated
Jul 8, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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