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

Abstract

<b>Objective:</b> 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. <p><b>Research Design and Methods:</b> 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]</p> <p><b>Results:</b> 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. </p> <b>Conclusions:</b> 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.