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Roux-en-Y gastric bypass increases glycaemic variability and time in hypoglycaemia in patients with obesity and pre-diabetes/type 2 diabetes mellitus: a prospective cohort study

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posted on 23.12.2020, 16:23 by Ibiyemi Ilesanmi, George Tharakan, Kleopatra Alexiadou, Preeshila Behary, Haya Alessimii, Candace Bovill-Taylor, Julia Kenkre, Sirazum Choudhury, Chedie Doyle, Sanjay Purkayastha, Alex Miras, Christos Tsironis, Harvinder Chahal, Stephen R. Bloom, Nick S. Oliver, Ahmed R. Ahmed, Bernard Khoo, Tricia M-M. Tan
Objective: Roux-en-Y gastric bypass (RYGB) is an established treatment for type 2 diabetes. The study objective was to establish RYGB’s effects on glycaemic variability (GV) and hypoglycaemia.

Research Design and Methods: Prospective observational study of 10 participants with pre-diabetes/Type 2 diabetes undergoing RYGB, studied before surgery (Pre), 1 month (1m), 1 year (1y) and 2 years (2y) post-surgery with continuous glucose measurement (CGM). A mixed meal test (MMT) was performed at Pre, 1m and 1y. [ClinicalTrials.gov NCT01945840]

Results: After RYGB, mean CGM glucose fell (at 1m, 1y and 2y), and GV increased (at 1y and 2y). Fifty percent (5/10) of participants exhibited a percentage time in range <3.0 mmol/L [54 mg/dl] (%TIR<3.0) greater than the consensus target of 1% at 1y or 2y. Peak glucagon-like peptide-1 (GLP-1) and glucagon area-under-curve (AUC) during MMT were respectively positively and negatively associated with contemporaneous %TIR<3.0.

Conclusions: Patients undergoing RYGB are at risk of developing post-bariatric hypoglycaemia due to a combination of reduced mean glucose, increased GV and increased GLP-1 response.


The prospective RYGB cohort study was funded by the MRC Experimental Challenge Grant (MR/K02115X/1) and other aspects of the study were supported by the National Institute for Health Research (NIHR) Imperial Biomedical Research Centre (BRC) Funding Scheme. The research study was also supported by the Imperial NIHR Clinical Research Facility. The Department of Metabolism, Digestion and Reproduction is funded by grants from the MRC and Biotechnology and Biological Sciences Research Council and is supported by the NIHR Imperial BRC Funding Scheme. The views expressed are those of the authors and not necessarily those of the abovementioned funders, the UK National Health Service (NHS), the NIHR, or the UK Department of Health.