Intensive Weight Loss Intervention Versus Bariatric Surgery for Adults With Severe and Complex Obesity: the LightBAR Randomised Trial

Official title

Intensive Weight Loss Intervention Versus Bariatric Surgery for Adults With Severe and Complex Obesity: the LightBAR Randomised Trial. Lighthouse Consortium on Obesity Management (LightCOM) Trial no 4

Overview

With this trial, the aim is to assess the benefits and harms of a non-surgical intensive weight loss intervention that includes total dietary replacements, behavioural support and weight-loss medication compared with bariatric surgery for people with severe and complex obesity. The interpretation of the results will help inform future care pathways for people with obesity in whom bariatric surgery is currently the only available effective treatment option.

Detailed description

In the LightBAR trial, an intensive weight loss (IWL) intervention will be compared with bariatric surgery. The IWL consists of three phases:

'Induction' phase (week 0-12 after randomisation): total dietary replacement (TDR) programme and behavioural support with weight loss medication (WLM) if rate of weight loss is insufficient.

'Weight loss continuation' phase (week 13-32 after randomisation): progression of dietary programme including reduction in use of TDR products, reintroduction of healthy foods, with behavioural support, introduction of physical activity, WLM (as required).

'Maintenance' phase (week 33-104 after randomisation): Continued healthy diet and physical activity with WLM (if required), with return to induction phase if weight regain occurs induction, weight loss continuation, maintenance. The IWL lasts two years, and includes total dietary replacements, behavioural support, and weight loss medication. Bariatric surgery will be standard Roux-en-Y gastric bypass or sleeve gastrectomy.

Interventions

• Behavioral Intensive weight loss intervention
  Intensive weight loss intervention, incl. total meal replacements, behavioural support, and weight loss medication
• Procedure Bariatric surgery
  Roux-en-Y Gastric Bypass (RYGB) or Sleeve Gastrectomy (SG)

Primary outcome measures

• MetS-Z [Time frame: 104 weeks after randomisation]

Secondary outcome measures (3)

• Weight [Time frame: 104 weeks after randomisation]
• Gait speed [Time frame: 104 weeks after randomisation]
• Short-Form-36, mental component score [Time frame: 104 weeks after randomisation]

Eligibility criteria

Please note that participants need to be invited in order to take part in the trial.

Inclusion criteria

• Aged 18 to 60 years (inclusive) at time of screening.
• Eligible for and willing to undergo bariatric surgery, i.e., fulfilment of criteria for bariatric surgery from the respective national health authorities:

• DK: BMI ≥ 35 kg/m2 with one or more of the following: T2D, severe hypertension, sleep apnoea requiring treatment, symptomatic arthrosis in lower extremities, female infertility related to overweight, or BMI>40 kg/m2 with other strong medical reasons for weight loss (28). Prior to surgery, an 8% weight loss is required as well as smoking cessation.
• UK: BMI of 35 kg/m2 to 40 kg/m2 and other significant disease (e.g., type 2 diabetes or high blood pressure), or BMI ≥40 kg/m2. Has been or is willing to receive intensive management in a specialist tier 3 obesity service (29).
• Fit for anaesthesia and surgery.
• Informed consent.

Exclusion criteria

• Prior bariatric or hiatal surgery, not including intragastric balloons or duodenal-jejunal bypass sleeve (Endobarrier™ or similar) if the device has been removed >1 year before screening.
• Use of any WLM (including liraglutide and semaglutide for diabetes) within last 3 months.
• Conditions that contraindicate or complicate total diet replacement (including type 1 diabetes or other diabetes requiring basal bolus insulin therapy or insulin pump therapy (for Denmark) and any diabetes requiring insulin therapy (for UK), phenylketonuria, or other conditions requiring strict adherence to special diets).
• Conditions that contraindicate or complicate treatment with GLP-1 receptor analogues (including history of pancreatitis or known allergies).
• Conditions that contraindicate or complicate bariatric surgery (GI motility disorders, large abdominal wall hernia, large hiatus hernia (>5cm), Crohn's disease, liver cirrhosis, or other conditions preventing laparoscopic bariatric surgery e.g. multiple previous abdominal surgery).
• Conditions that contraindicate or complicate study adherence and bariatric surgery (mental disorder, unstable psychiatric disease, recent history of alcohol/medication abuse, cancer treatment within 5 years).
• Pregnant or planning pregnancy in the next two years or currently breast feeding.
• Not achieving a 5% weight loss within 12 weeks prior to randomisation.
• People taking part in other research involving multidisciplinary obesity treatment that would compromise their participation in this trial.
• Another member of the household enrolled in the trial.
• Diagnosis of or treatment for severe eating disorder within the last 6 months.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Double blind

Primary purpose

Treatment

Study locations

United Kingdom · 6 centers

• St Richard's Hospital — Chichester
• Hartlands Hospital, University Hospitals Birmingham NHS Foundation Trust — Birmingham
• Southmead Hospital, North Bristol NHS Trust — Bristol
• The Whittington Hospital — London
• Sunderland Royal Hospital — Sunderland
• Musgrove Park Hospital, Somerset Foundation NHS Trust — Taunton

Denmark · 4 centers

• Steno Diabetes Center Aarhus, Aarhus Universitets Hospital — Aarhus
• The Department of Medicine and Department of Surgery, University Hospital of South West Ju — Esbjerg
• The Department of Medicine and the Gastro Unit, Copenhagen University Hospital - Amager an — Hvidovre
• Department of Surgery, Viborg Regional Hospital — Viborg

Publications

• Tomova-Olsen SA, Kousgaard MB, Jensen KT, Reventlow S, Christiansen AL, Bojsen-Moller KN, Dirksen C, Overbeck G. Time, money, and weight loss: a qualitative study exploring patients' perspectives on randomization for bariatric surgery vs. an intensive non-surgical weight loss program. Trials. 2025 Apr 4;26(1):121. doi: 10.1186/s13063-025-08816-8. PMID 40186310

Identifiers

NCT: NCT06309238 · LightBAR

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗