Sustaining Health After an Intensive Weight-loss Pro-gramme

Since 2021 Copenhagen University Hospital - Hvidovre, Denmark, has offered a 2-year, highly specialised, intensive clinical weight loss programme to patients living with severe and complex obesity, who due to somatic and/or psychiatric comorbidity are not eligible for bariatric surgery. This understudied group often lacks treatment options despite significant functional impairment and high healthcare costs. The programme is based on an intensive dietary and behavioural support provided by trained dieti-cians. It begins with an 8-week period of full TDR of 800 kcal/day. During this initial phase the patients have bimonthly consultations with the dieticians, a schedule which continues throughout the first year. At week 6-8 the patients begin the treatment with GLP-1 receptor agonist (GLP-1-RA). Until medio 2024 patients without diabetes were treated with Liraglutide, thereafter Semaglutide has been used. After week 8 the patients transition back to a normal balanced diet, guided by the dieticians. Shorter periods of TDR can be used as a rescue-strategy in cases of weight-regain during the treat-ment period. In their second year of treatment the frequency of dietician consultations de-creases to once a month. Patients are scheduled to see a physician at the beginning of the treatment, at 4 months, at 12 months and at 21 months. At the end of the programme dieticians and physicians' advice on weight loss maintenance strategies including possibilities for cessation/reducing dose of weight loss medication but there are no clinical follow up visits.

Overall research question What is the durability and long-term health effects of a hospital-based IWL-treatment programme, with specific attention to cardiometabolic health, body-composition and health-related quality of life, at least 1 year after cessation of treatment in a clinical cohort of patients living with severe obesity and multimorbidity?

Study design This study is a post-intervention observational follow-up (FU) study, evaluating the durability of the IWL-treatment offered to patients at Hvidovre Hospital since 2022. This study is a substudy under the study-compilation SHAPe, consisting of a quality-assurance project evaluating the treatment programme, this post-intervention observational FU-study, a qualitative study exploring psychosocial and socio-economic precarity mediate adherence to the programme and durability of health outcomes and a societal and economic impact study to evaluate the impact on total health care costs and labour market attachment.

The FU-visit will consist of a single investigation day at Hvidovre Hospital and will be scheduled at least 12 months after completing the treatment programme. Participants will provide blood and urine samples, undergo anthropometric measurements (weight, height, waist circumference), blood pressure assessment, and body composition analysis. They will also complete the SF-36 questionnaire and a . Additionally, they will be asked for consent to link their data to national registries for a 10-year follow-up on hospital admissions, medication use, and employment status. Biological samples may be stored for future analysis of metabolic biomarkers related to weight regulation.

Due to the clinical nature of the study, it is exploratory and descriptive and hence does not include hypothesis testing, but instead an overall research question. Thus, it is designed with a non-hierarchical outcome structure, though with certain patient-centred "key outcomes." These outcomes have been chosen to reflect what is important for patients lives with skeletal muscle mass, health-related quality of life and weight as key outcomes. Additionally, we will explore the following outcomes: fat-mass, waist circumference, use of weight-loss medication, lower body strength, blood-pressure, HbA1c, lipid levels and potential proteomic biomarkes associated with regain vs weight maintenance. We aim to include 200 participants in the FU study.