Understanding why some patients don't lose weight after bariatric surgery

Why do Some Patients Respond Better Than Others to Bariatric Surgery?

Not applicable Interventional Imperial College London · NCT05404061

This study is trying to find out why some people don’t lose as much weight as expected after bariatric surgery, focusing on the role of gut hormones to help improve their results.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment220 (estimated)
Ages18 Years to 70 Years
SexAll
SponsorImperial College London Academic / other
Locations1 site (London)
Trial IDNCT05404061 on ClinicalTrials.gov

What this trial studies

This study focuses on patients who have undergone bariatric surgery but are classified as 'poor responders,' meaning they either lose less weight than expected or regain weight after initial loss. The research aims to investigate the role of gut hormones in these patients to better understand their unique challenges. By identifying the factors that contribute to poor weight loss outcomes, the study seeks to develop targeted interventions to improve results for this specific group. Participants will include individuals aged 18-70 who have had bariatric surgery at least one year prior or are awaiting surgery.

Who should consider this trial

Good fit: Ideal candidates are individuals aged 18-70 who have previously undergone bariatric surgery and are classified as poor responders.

Not a fit: Patients who have not undergone bariatric surgery or those with conditions that may interfere with the study will not benefit.

Why it matters

Potential benefit: If successful, this study could lead to improved treatment strategies for patients who struggle with weight loss after bariatric surgery.

How similar studies have performed: While studies on bariatric surgery outcomes exist, this specific focus on poor responders and gut hormones is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Aged 18 -70 years.
* Male or female.
* Previous bariatric surgery for obesity and/or diabetes (studies 1 and 2).
* ≥1 year interval after bariatric surgery (studies 1 and 2).
* Awaiting bariatric surgery at the Imperial Weight Centre (study 3)
* Able to give informed consent.

Exclusion Criteria:

* History of any medical, psychological or other condition, or use of any medications, including over-the-counter products, which, in the opinion of the investigators, would either interfere with the study or potentially cause harm to the volunteer.
* Without access at home to a telephone or other factor likely to interfere with ability to participate reliably in the study.
* Pregnancy or breastfeeding.
* Unable to maintain adequate contraception for the duration of the study and for one month afterwards.
* History of hypersensitivity to any of the components of the subcutaneous infusions.
* Donated blood during the preceding 3 months or intention to do so before the end of the study.
* Any other co-morbidity that would compromise the validity of the study or the safety of the participant such as heart failure or clinically apparent cardiovascular disease.
* Anatomical or endocrinological pathology causing poor weight loss or weight regain
* Uncontrolled hypertension (systolic blood pressure of 160 mmHg or above and/or diastolic blood pressure of 100 mmHg or above)
* Participation in a research study within the last two months.
* Unable to speak English (this is relevant to answering the psychological questionnaires)

Where this trial is running

London

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Bariatric Surgery CandidateObesity, MorbidDiabetes Mellitus, Type 2
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.