Does muscle strength and abdominal wall function improve with weight loss after gastric bypass?
| ISRCTN | ISRCTN17263619 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN17263619 |
| ClinicalTrials.gov (NCT) | Nil known |
| Clinical Trials Information System (CTIS) | Nil known |
| Protocol serial number | GUMP |
| Sponsor | County Council of Västerbotten (Västerbottens läns landsting) |
| Funder | Umeå Universitet |
- Submission date
- 27/01/2017
- Registration date
- 15/03/2017
- Last edited
- 11/09/2025
- Recruitment status
- No longer recruiting
- Overall study status
- Ongoing
- Condition category
- Nutritional, Metabolic, Endocrine
Plain English summary of protocol
Background and study aims
As obesity is becoming more common worldwide, more people are undergoing weight-loss surgery such as primary laparoscopic gastric bypass, where the digestive system is re-routed past most of the stomach so that less food is digested and it takes much less food to feel full. Weight-loss surgery often has good results on obesity and related diseases. Little is known, however, about what happens to muscle strength and the abdominal wall after weight-loss surgery. Previous studies have shown that thigh muscle strength is reduced after weight-loss surgery. The aim of this study is to collect information to see whether weight loss causes muscular strength problems that could have an effect on the decision to undergo surgery.
Who can participate?
Patients undergoing primary laparoscopic gastric bypass.
What does the study involve?
Blood samples are taken to measure connective tissue and wound healing markers before surgery and 1 month, 3 months and 6 months, plus 2 och 3 years after surgery. Tissue samples of the abdominal wall are collected during surgery and are also tested for connective tissue and wound healing markers. Muscle strength in the abdominal wall and thigh is measured once before, 6 months and 3-6 years after surgery. Physical ability and abdominal wall function are also measured using questionnaires before, 6 months and 3-6 years after surgery. Endoanal ultrasound is performed before surgery and 6 months after, with related questionnaires.
Persons included in the muscle strength and blood and tissue sample study will also be invited to attend semi-structured interviews using an interview guide, conducted in person or by means of video conferencing. An estimated 10 to 25 persons need to be interviewed to attain information strength. The interviews will take place one to three years after gastric bypass surgery. A later interview study will be held three to six years after surgery and focus on changes in abdominal wall function. The interviews will then be transcribed and analyzed with qualitative content analysis, where meaning units are identified, condensed and coded, and categories and themes are formulated in order to report a representative conclusion of the collected narratives.
What are the possible benefits and risks of participating?
The muscle measurements are generally well tolerated and can heighten awareness of physical ability after surgery. The extra blood samples required in this study can sometimes be taken together with regular blood samples before and after surgery. The small (5 mm) tissue samples are not expected to be noticed in any way by the participants, as these are taken during surgery. The endoanal ultrasound examination is intrusive but takes no longer than approximately 2 minutes.
The interview is an additional and possibly time-consuming activity for the participants. The interview is expected to take no longer than 30-45 minutes, depending on the scope of what the participant wants to talk about, and if other health-related matters come up. However, they can decide on the place and time, and whether they wish to participate in person or via video conferencing, in order to support participation.
Where is the study run from?
1. Lycksele Hospital (Sweden)
2. Uppsala University Hospital (Sweden)
When is the study starting and how long is it expected to run for?
October 2015 to December 2027
Who is funding the study?
Umeå University (Sweden)
Who is the main contact?
Dr Jeff Wennerlund, Jeff.Wennerlund@umu.se
Contact information
Public
Department of Surgery and Orthopedics
Lycksele Hospital
Lycksele
92182
Sweden
 ORCID ID |
0000-0003-0603-751X |
|---|---|
| Phone | +46 (0)950 39124 |
| Jeff.Wennerlund@umu.se |
Scientific, Principal investigator
Department of Surgery and Perioperative Sciences
Umeå University
Umeå
901 87
Sweden
| Phone | +46 (0)90 7852909 |
|---|---|
| karin.strigard@umu.se |
Study information
| Primary study design | Observational |
|---|---|
| Study design | Clinical observational study and semi-structured interviews with qualitative content analysis |
| Secondary study design | Case series |
| Study type | Participant information sheet |
| Scientific title | Does muscle strength and abdominal wall function improve with weight loss after gastric bypass? A clinical observational study |
| Study acronym | GUMP |
| Study objectives | Research questions: 1. Does bariatric surgery improve abdominal wall function after weight loss? 2. Does weight loss after bariatric surgery cause problems with the abdominal wall? |
| Ethics approval(s) | Approved 10/01/2016, Regional Ethics Review Board, Umeå (Samverkanshuset, Umeå University, Umeå, 901 87, Sweden; +46 (0)10-4750800; registrator@etikprovning.se), ref: 2015/367-31 Since this approval, this regional board has been replaced by a national agency, the Swedish Ethical Review Authority |
| Health condition(s) or problem(s) studied | Obesity, weight loss, muscle strength |
| Intervention | Current interventions as of 11/09/2025: Blood samples are collected to analyze matrix metalloproteinases, hyaluron och associated biomarkers before surgery, as well as 1 month, 3 months, 6 months, plus 2 and 3 years after. Abdominal wall muscle and fascia biopsies are also collected during surgery for analysis. Abdominal wall and thigh strength are measured with the use of BioDex System 3 before, 6 months, and 3-6 years after gastric bypass. Physical ability and abdominal wall function are also measured using the Ventral Hernia Pain Questionnaire (VHPQ), International Physical Ability Questionnaire (IPAQ) and Visual Analog Scale for abdominal wall function (VAS), all once before, 6 months and 3-6 years after surgery. Endoanal ultrasound is performed before and 6 months after surgery, together with Wexner Score and Low Anterior Resection Syndrome Score (LARS). Two qualitative interview studies using Qualitative Content Analysis designed to capture experiences of change of bodily function after weight loss induced by gastric bypass surgery. The first study will take place one to three years postoperatively and focus on the changes in physical activity. A later interview study 3 to 6 years after surgery will focus on abdominal wall function. ______ Previous interventions as of 13/12/2023: Blood samples are collected to analyze matrix metalloproteinases, hyaluron och associated biomarkers before surgery, as well as 1 month, 3 months, 6 months, plus 2 and 3 years after. Abdominal wall muscle and fascia biopsies are also collected during surgery for analysis. Abdominal wall and thigh strength are measured with the use of BioDex System 3 before, 6 months, and 3-6 years after gastric bypass. Physical ability and abdominal wall function are also measured using the Ventral Hernia Pain Questionnaire (VHPQ), International Physical Ability Questionnaire (IPAQ) and Visual Analog Scale for abdominal wall function (VAS), all once before, 6 months and 3-6 years after surgery. Two qualitative interview studies using Qualitative Content Analysis designed to capture experiences of change of bodily function after weight loss induced by gastric bypass surgery. The first study will take place one to three years postoperatively and focus on the changes in physical activity. A later interview study 3 to 6 years after surgery will focus on abdominal wall function. ______ Previous interventions as of 03/03/2022: Blood samples are collected to analyze matrix metalloproteinases before surgery, as well as 2 weeks, 1 month, 3 months, 6 months, and 2 years after. Abdominal wall muscle and fascia biopsies are collected during surgery for analysis of matrix metalloproteinases. Abdominal wall and thigh strength are measured with the use of BioDex System 3 before and 6 months after gastric bypass. Physical ability and abdominal wall function are also measured using the Ventral Hernia Pain Questionnaire (VHPQ), International Physical Ability Questionnaire (IPAQ) and Visual Analog Scale for abdominal wall function (VAS), all once before and once 6 months after surgery. A qualitative interview study designed to capture experiences of change of bodily function after weight loss induced by gastric bypass surgery. Interviews will take place approximately one to three years postoperatively. ______ Previous interventions as of 21/04/2020: Blood samples are collected to analyze matrix metalloproteinases before surgery, as well as 2 weeks, 1 month, 3 months, 6 months, and 2 years after. Abdominal wall muscle and fascia biopsies are collected during surgery for analysis of matrix metalloproteinases. Abdominal wall and thigh strength are measured with the use of BioDex System 3 before and 6 months after gastric bypass. Physical ability and abdominal wall function are also measured using Ventral Hernia Pain Questionnaire (VHPQ), International Physical Ability Questionnaire (IPAQ) and Visual Analog Scale for abdominal wall function (VAS), all once before and once 6 months after surgery. ______ Previous interventions: Blood samples are collected to analyze matrix metalloproteinases before surgery, as well as 2 weeks, 1 month, 3 months and 6 months after. Abdominal wall muscle and fascia biopsies are collected during surgery for analysis of matrix metalloproteinases. Abdominal wall and thigh strength are measured with the use of BioDex System 3 before and 6 months after gastric bypass. Physical ability and abdominal wall function are also measured using Ventral Hernia Pain Questionnaire (VHPQ), International Physical Ability Questionnaire (IPAQ) and Visual Analog Scale for abdominal wall function (VAS), all once before and once 6 months after surgery. |
| Intervention type | Other |
| Primary outcome measure(s) |
Current primary outcome measure as of 11/09/2025: |
| Key secondary outcome measure(s) |
There are no secondary outcome measures |
| Completion date | 31/12/2027 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | All |
| Sex | All |
| Target sample size at registration | 100 |
| Total final enrolment | 99 |
| Key inclusion criteria | 1. Patients eligible for primary laparoscopic gastric bypass 2. All patients undergoing primary laparoscopic gastric bypass at Lycksele Hospital are eligible for recruitment 3. Patients undergoing surgery in Uppsala are eligible for collection of blood and tissue samples only 4. All ages |
| Key exclusion criteria | If, after inclusion, no or different surgery is planned |
| Date of first enrolment | 30/09/2016 |
| Date of final enrolment | 30/09/2022 |
Locations
Countries of recruitment
- Sweden
Study participating centres
Lycksele Hospital
Lycksele
92182
Sweden
Uppsala
75185
Sweden
Results and Publications
| Individual participant data (IPD) Intention to share | Yes |
|---|---|
| IPD sharing plan summary | Available on request |
| IPD sharing plan | The datasets generated during and/or analysed during the current study are/will be available upon request from Dr Jeff Wennerlund (Jeff.Wennerlund@umu.se). |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Participant information sheet | Participant information sheet | 11/11/2025 | 11/11/2025 | No | Yes |
| Study website | Study website | 11/11/2025 | 11/11/2025 | No | Yes |
Editorial Notes
11/09/2025: The interventions, primary outcome measures, and the publication and dissemination plan were changed.
03/03/2025: The following changes were made to the trial record:
1. The scientific contact was changed.
2. The plain English summary was updated to reflect these changes.
13/12/2023: The following changes were made to the trial record:
1. Ethics approval details and total final enrolment added.
2. The overall study end date was changed from 21/09/2025 to 31/12/2027.
3. The interventions, primary outcome measures, study participating centre address and publication and dissemination plan were updated.
4. The plain English summary was updated accordingly.
5. The intention to publish date was changed from 30/04/2026 to 01/01/2028.
29/09/2022: The following changes were made to the trial record:
1. The overall end date was changed from 31/10/2024 to 21/09/2025.
2. The intention to publish date was changed from 30/04/2025 to 30/04/2026.
3. The plain English summary was updated to reflect these changes.
03/03/2022: The following changes have been made:
1. The recruitment end date has been changed from 31/08/2022 to 30/09/2022.
2. The study design has been changed from "Clinical observational study" to "Clinical observational study and semi-structured interviews with qualitative content analysis".
3. The intervention has been updated.
4. The primary outcome measure has been updated.
5. The plain English summary has been updated.
6. The publication and dissemination plan has been updated.
21/04/2020: The following changes were made to the trial record:
1. The recruitment end date was changed from 31/03/2020 to 31/08/2022.
2. The overall end date was changed from 01/05/2021 to 31/10/2024.
3. The intention to publish date was changed from 01/09/2021 to 30/04/2025.
4. The interventions were changed.
5. The primary outcome measure was changed.
6. The plain English summary was updated to reflect these changes.
08/04/2019: The following changes were made:
1. The recruitment end date was changed from 31/03/2019 to 31/03/2020.
2. The overall trial end date was changed from 01/05/2020 to 01/05/2021.
3. The intention to publish date was changed from 01/09/2020 to 01/09/2021.
09/08/2018: The following changes have been made to the trial record:
1. The overall trial end date was changed from 01/09/2019 to 01/05/2020
2. The recruitment end date was changed from 31/03/2018 to 31/03/2019
3. The intention to publish date was changed from 01/12/2019 to 01/09/2020
