Working...
ClinicalTrials.gov
ClinicalTrials.gov Menu

Effects of Gastric Bypass Surgery and Calcium Metabolism and the Skeleton

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT01330914
Recruitment Status : Completed
First Posted : April 7, 2011
Results First Posted : January 7, 2016
Last Update Posted : March 15, 2019
Sponsor:
Information provided by (Responsible Party):
VA Office of Research and Development

Study Type Observational
Study Design Observational Model: Cohort;   Time Perspective: Prospective
Conditions Obesity, Morbid
Gastric Bypass
Enrollment 55
Recruitment Details Women and men 25-70 years of age were recruited from two academic bariatric surgery centers (the University of California, San Francisco and the San Francisco Veterans Affairs Medical Center), where surgeons used the same standardized surgical approach to Roux-en-Y gastric bypass.
Pre-assignment Details  
Arm/Group Title Gastric Bypass Surgery Patients
Hide Arm/Group Description Obese men and women undergoing gastric bypass surgery
Period Title: Overall Study
Started 55
Completed 48
Not Completed 7
Reason Not Completed
Withdrawal by Subject             4
No longer eligible (sleeve gastrectomy)             3
Arm/Group Title Gastric Bypass Surgery Patients
Hide Arm/Group Description Obese men and women undergoing gastric bypass surgery
Overall Number of Baseline Participants 55
Hide Baseline Analysis Population Description
[Not Specified]
Age, Continuous  
Mean (Standard Deviation)
Unit of measure:  Years
Number Analyzed 55 participants
45.8  (11.2)
Sex: Female, Male  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 55 participants
Female
44
  80.0%
Male
11
  20.0%
Ethnicity (NIH/OMB)  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 55 participants
Hispanic or Latino
6
  10.9%
Not Hispanic or Latino
49
  89.1%
Unknown or Not Reported
0
   0.0%
Race (NIH/OMB)  
Measure Type: Count of Participants
Unit of measure:  Participants
Number Analyzed 55 participants
American Indian or Alaska Native
1
   1.8%
Asian
3
   5.5%
Native Hawaiian or Other Pacific Islander
2
   3.6%
Black or African American
12
  21.8%
White
37
  67.3%
More than one race
0
   0.0%
Unknown or Not Reported
0
   0.0%
Region of Enrollment  
Measure Type: Number
Unit of measure:  Participants
United States Number Analyzed 55 participants
55
Menopausal status  
Measure Type: Number
Unit of measure:  Participants
Number Analyzed 55 participants
Premenopausal 30
Postmenopausal 14
N/A (Men) 11
Weight  
Mean (Standard Deviation)
Unit of measure:  Kg
Number Analyzed 55 participants
122.7  (19.3)
Body mass index  
Mean (Standard Deviation)
Unit of measure:  Kg/m2
Number Analyzed 55 participants
44.2  (7.0)
Percentage body fat  
Mean (Standard Deviation)
Unit of measure:  Percentage of body fat
Number Analyzed 55 participants
46.7  (5.9)
Diabetes status  
Measure Type: Number
Unit of measure:  Participants
Number Analyzed 55 participants
Diabetic 22
Not diabetic 33
Femoral neck areal bone mineral density (DXA)  
Mean (Standard Deviation)
Unit of measure:  G/cm2
Number Analyzed 55 participants
0.949  (0.133)
Spine volumetric bone mineral density (QCT)  
Mean (Standard Deviation)
Unit of measure:  G/cm3
Number Analyzed 55 participants
0.159  (0.036)
1.Primary Outcome
Title Change in Intestinal Calcium Absorption
Hide Description

Change in fractional calcium absorption, determined by dual stable isotope method.

Fractional calcium absorption is the fraction of ingested calcium that is absorbed, which is expressed here as the percentage of ingested calcium that is absorbed. The 6-month change is the mean difference in percentage absorption between time points. For example, if fractional calcium absorption were to decrease from 30% preoperatively to 25% at the 6-month postoperative time point, the change in fractional calcium absorption would be -5%.

Time Frame 6 months (between baseline and 6 months)
Hide Outcome Measure Data
Hide Analysis Population Description
Participants from the cohort who underwent assessment of fractional calcium absorption preoperatively and 6 months postoperatively
Arm/Group Title Gastric Bypass Surgery Patients
Hide Arm/Group Description:
Obese men and women undergoing gastric bypass surgery
Overall Number of Participants Analyzed 33
Mean (Standard Deviation)
Unit of Measure: % of ingested calcium that is absorbed
-25.8  (15.3)
2.Secondary Outcome
Title Areal Bone Mineral Density (BMD) at the Femoral Neck
Hide Description Areal BMD at the femoral neck by dual-energy X-ray absorptiometry (DXA). The 12-month change is the percentage change between the 12 month and baseline time points.
Time Frame 12 months post-operatively (between baseline and 12 months)
Hide Outcome Measure Data
Hide Analysis Population Description
participants who underwent DXA at pre-op and 12-month post-op time points
Arm/Group Title Gastric Bypass Surgery Patients
Hide Arm/Group Description:
Obese men and women undergoing gastric bypass surgery
Overall Number of Participants Analyzed 45
Mean (Standard Deviation)
Unit of Measure: percent of baseline value
-8.0  (4.9)
3.Secondary Outcome
Title Trabecular Number at the Tibia
Hide Description Trabecular number at the tibia by high-resolution peripheral quantitative computed tomography (HR-pQCT). The 12-month change is the percentage change between the 12 month and baseline time points. HR-pQCT images were analyzed using the manufacturer's standard clinical evaluation protocol, with trabecular structure extracted using a threshold-based binarization process.
Time Frame 12 months post-operatively (between baseline and 12 months)
Hide Outcome Measure Data
Hide Analysis Population Description
participants who underwent HR-pQCT at pre-op and 12-month post-op time points
Arm/Group Title Gastric Bypass Surgery Patients
Hide Arm/Group Description:
Obese men and women undergoing gastric bypass surgery
Overall Number of Participants Analyzed 44
Mean (Standard Deviation)
Unit of Measure: percent of baseline value
-4.6  (8.4)
Time Frame 12 months
Adverse Event Reporting Description Participants were asked about interim adverse events at baseline, 6-month, and 12-month study visits. Adverse events volunteered by participants between study visits were also recorded.
 
Arm/Group Title Gastric Bypass Surgery Patients
Hide Arm/Group Description Obese men and women undergoing gastric bypass surgery
All-Cause Mortality
Gastric Bypass Surgery Patients
Affected / at Risk (%)
Total   --/--    
Show Serious Adverse Events Hide Serious Adverse Events
Gastric Bypass Surgery Patients
Affected / at Risk (%) # Events
Total   1/55 (1.82%)    
Renal and urinary disorders   
Nephrolithiasis   1/55 (1.82%)  1
Indicates events were collected by systematic assessment
Show Other (Not Including Serious) Adverse Events Hide Other (Not Including Serious) Adverse Events
Frequency Threshold for Reporting Other Adverse Events 1.82%
Gastric Bypass Surgery Patients
Affected / at Risk (%) # Events
Total   3/55 (5.45%)    
Gastrointestinal disorders   
Constipation   1/55 (1.82%)  1
Dyspepsia   2/55 (3.64%)  2
Renal and urinary disorders   
Nephrolithiasis   1/55 (1.82%)  1
Indicates events were collected by systematic assessment
Certain Agreements
Principal Investigators are NOT employed by the organization sponsoring the study.
There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.
Results Point of Contact
Name/Title: Dr. Anne Schafer
Organization: San Francisco Veterans Affairs Medical Center
Phone: (415) 221-4810 ext 24895
Responsible Party: VA Office of Research and Development
ClinicalTrials.gov Identifier: NCT01330914     History of Changes
Other Study ID Numbers: ENDB-007-10F
1IK2CX000549-01 ( U.S. NIH Grant/Contract )
First Submitted: April 5, 2011
First Posted: April 7, 2011
Results First Submitted: December 2, 2015
Results First Posted: January 7, 2016
Last Update Posted: March 15, 2019