Single-Centre, Triple-Blinded, Randomised, 1-Year, Parallel-Group, Superiority Study to Compare the Effects of Roux-En-Y Gastric
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Open access Protocol BMJ Open: first published as 10.1136/bmjopen-2018-024573 on 4 June 2019. Downloaded from Single-centre, triple-blinded, randomised, 1-year, parallel-group, superiority study to compare the effects of Roux-en-Y gastric bypass and sleeve gastrectomy on remission of type 2 diabetes and β-cell function in subjects with morbid obesity: a protocol for the Obesity surgery in Tønsberg (Oseberg) study Heidi Borgeraas,1 Jøran Hjelmesæth,1,2 Kåre Inge Birkeland,3 Farhat Fatima,1,2 John Olav Grimnes,4 Hanne L Gulseth,2 Erling Halvorsen,4 Jens Kristoffer Hertel,1 Tor Olav Widerøe Hillestad,4 Line Kristin Johnson,1 Tor-Ivar Karlsen,1,5 To cite: Borgeraas H, Ronette L Kolotkin,6,7 Nils Petter Kvan,4 Morten Lindberg,8 Jolanta Lorentzen,1,2 Hjelmesæth J, Birkeland KI, 1,9 1,10 1,2 11 et al. Single-centre, triple- Njord Nordstrand, Rune Sandbu, Kathrine Aagelen Seeberg, Birgitte Seip, 1,2 12 1 blinded, randomised, 1-year, Marius Svanevik, Tone Gretland Valderhaug, Dag Hofsø parallel-group, superiority study to compare the effects of Roux-en-Y gastric bypass and sleeve gastrectomy on ABSTRACT remission of type 2 diabetes and Strengths and limitations of this study β-cell function in subjects with Introduction Bariatric surgery is increasingly recognised http://bmjopen.bmj.com/ morbid obesity: a protocol for as an effective treatment option for subjects with type ► Study design—randomised, triple-blinded superior- the Obesity surgery in Tønsberg 2 diabetes and obesity; however, there is no conclusive ity trial. (Oseberg) study. BMJ Open evidence on the superiority of Roux-en-Y gastric bypass ► Numerous clinically relevant secondary endpoints 2019;9:e024573. doi:10.1136/ or sleeve gastrectomy. The Oseberg study was designed bmjopen-2018-024573 including gastro-oesophageal reflux disease, fatty to compare the effects of gastric bypass and sleeve liver disease, cardiovascular risk factors, bone me- ► Prepublication history and gastrectomy on remission of type 2 diabetes and β-cell tabolism and patient-reported outcome measures additional material for this paper function. covering health-related quality of life, psycholog- are available online. To view, Methods and analysis Single-centre, randomised, triple- ical distress, eating behaviour and gastrointestinal please visit the journal (http:// on October 1, 2021 by guest. Protected copyright. blinded, two-armed superiority trial carried out at the symptoms. dx. doi. org/ 10. 1136/ bmjopen- Morbid Obesity Centre at Vestfold Hospital Trust in Norway. 2018- 024573). ► Predefined algorithms for optimising medications Eligible patients with type 2 diabetes and obesity were and supplementations related to primary and sec- Received 15 June 2018 randomly allocated in a 1:1 ratio to either gastric bypass ondary outcomes. Revised 13 March 2019 or sleeve gastrectomy. The primary outcome measures are ► Insulin secretion and action are calculated using Accepted 15 April 2019 (1) the proportion of participants with complete remission both oral and intravenous glucose tolerance tests. of type 2 diabetes (HbA1c≤6.0% in the absence of blood ► The sample size is limited and may, thus, not provide glucose-lowering pharmacologic therapy) and (2) β-cell sufficient statistical power to detect clinically rele- © Author(s) (or their function expressed by the disposition index (calculated vant differences in secondary outcomes. employer(s)) 2019. Re-use using the frequently sampled intravenous glucose tolerance permitted under CC BY-NC. No test with minimal model analysis) 1 year after surgery. commercial re-use. See rights Ethics and dissemination The protocol of the current Trial registration number NCT01778738;Pre-results. and permissions. Published by study was reviewed and approved by the regional ethics BMJ. committee on 12 September 2012 (ref: 2012/1427/REK For numbered affiliations see sør-øst B). The results will be disseminated to academic INTRODUCTION end of article. and health professional audiences and the public via Bariatric surgery is associated with long- Correspondence to publications in international peer-reviewed journals and term weight reduction and improvement of Dr Heidi Borgeraas; conferences. Participants will receive a summary of the comorbidities, but also with adverse events heibor@ siv. no main findings. and side effects.1 2 Roux-en-Y gastric bypass Borgeraas H, et al. BMJ Open 2019;9:e024573. doi:10.1136/bmjopen-2018-024573 1 Open access was for many years considered the ‘gold standard’ of deficiencies, surgical complications and side effects, need BMJ Open: first published as 10.1136/bmjopen-2018-024573 on 4 June 2019. Downloaded from bariatric surgery, but recently sleeve gastrectomy, a tech- further examination. nically easier and faster to perform procedure, has gained popularity and is now the most common bariatric proce- Objectives dure in the USA.3 Primary objectives For subjects with type 2 diabetes and obesity, bariatric The primary objectives of this study are to assess the effects surgery is a particularly effective treatment option, and of gastric bypass and sleeve gastrectomy on glycaemic a number of randomised trials have demonstrated the control, diabetes remission and β-cell function. superiority of surgery over medical care for glycaemic 4–9 Secondary objectives control and remission of diabetes. The improved glycaemic homoeostasis following bariatric surgery is Secondary objectives are to explore changes in variables to a large extent explained by the hypocaloric state that are related to the primary endpoints of the study and weight reduction. However, as improvements often (ie, body weight and composition, insulin sensitivity, liver are observed even before changes in body weight occur, fat content, energy intake, stomach emptying rate and some of the effects appear to be independent of weight intestinal microbiota). Moreover, we will explore cardio- loss and possibly related to the specific surgical proce- vascular risk factors influenced by weight reduction and dure. Both gastric bypass and sleeve gastrectomy reduce possibly by changes in gut hormones (ie, blood pressure, the size of the stomach, but only gastric bypass includes arterial stiffness, albuminuria and lipids). Finally, we will a bypass of the duodenum and proximal small intestine. examine possible differences in vitamin and mineral Thus, particularly, after gastric bypass, there is a rapid deficiencies, bone density, gastro-oesophageal reflux delivery of undigested food to the small intestine that disease, hypoglycaemia, dumping syndrome, health-re- enhances the release of gut-derived incretin hormones, lated quality of life, psychological distress, obesity-related such as glucagon-like peptide-1 (GLP-1), which further symptoms, eating behaviour, nutrient intake, gastrointes- stimulate insulin secretion from pancreatic β-cells. tinal symptoms and surgical and medical complications Indeed, greater enhancement in postprandial GLP-1 related to the two operations. levels have been observed after gastric bypass compared Trial design with sleeve gastrectomy,10 while others have reported This study is a single-centre, triple-blinded, two-armed no significant differences.11–13 The higher postprandial superiority trial randomising patients with type 2 diabetes incretin hormone levels may be causally linked with the and obesity in a 1:1 allocation ratio to either gastric bypass improved -cell function observed after gastric bypass14–16 β or sleeve gastrectomy. and sleeve gastrectomy.17 However, bariatric surgery is also accompanied by changes in other gut-derived and pancreatic-derived hormones, which directly or indirectly http://bmjopen.bmj.com/ 18 METHODS AND ANALYSIS influence glycaemic control. Study setting A limited number of high-quality studies have compared The study is carried out at the Morbid Obesity Centre the effect of gastric bypass and sleeve gastrectomy on at Vestfold Hospital Trust in Norway, a tertiary health- remission of type 2 diabetes. Prior to the initiation of care centre. The centre performs between 250 and 300 the present study, only one randomised controlled study bariatric procedures (gastric bypass and sleeve gastrec- had addressed glycaemic control in subjects with type 2 tomy) annually and about 25% of the patients have type 2 diabetes and obesity after gastric bypass and sleeve gastrec- diabetes.2 In 2012, when the Oseberg study was initiated, 19 on October 1, 2021 by guest. Protected copyright. tomy. The STAMPEDE trial showed similar reduction in sleeve gastrectomy accounted for approximately 10% of HbA1c 1 year after the two surgical procedures. In the bariatric procedures at our centre, increasing to approxi- following years, results from comparable randomised mately 40% in 2017. controlled trials have been published20–23 including 3 and 4 24 5 years follow-up data from the STAMPEDE trial. The Patient and public involvement remission rates of type 2 diabetes between the two proce- The steering committee includes a patient representative dures have not been statistically different in these trials. (MHK) to make sure that the patients’ voices are heard. Thus, there is currently no conclusive evidence showing The burden of the interventions will be assessed using the superiority of gastric bypass or sleeve gastrectomy for several patient-reported outcome measures question- patients with type 2 diabetes and obesity. Also, the impact naires, regarding several aspects of health-related quality of altered insulin secretion and action, gut microbiota, of life as