The usefulness of continuous glucose monitoring in the diagnostic approach to hypoglycemia after metabolic surgery

Abstract

Post-bariatric hypoglycemia (PBH) is an underdiagnosed complication of metabolic surgery, resulting in reduced quality of life and weight gain. There is currently no gold standard for the diagnosis of PBH. Although various guidelines and consensuses do not consider continuous glucose monitoring (CGM) a valid diagnostic tool, currently available CGM devices have adequate accuracy for euglycemia and hyperglycemia and have improved accuracy for hypoglycemia over time. This has expanded the use of CGM in the non-diabetic population and may be a useful tool in PBH, but evidence in this population is limited. CGM provides a real-time assessment of glucose fluctuations and variability, providing insights that standard diagnostic tools such as the oral glucose tolerance test (OGTT) and the mixed meal test (MMT) cannot capture in real-world settings. CGM can provide detailed information on the immediate dynamic changes in glucose levels and glycemic profile that reflect the patient’s “real life” situation, assess risk factors for PBH such as postoperative glycemic variability, and enable objective assessment of clinical response to nutritional and pharmacological therapy. Currently, there are limitations to its use in patients with PBH, but evidence of its usefulness in the management of these patients has increased in recent years. The aim of this narrative review is to highlight the benefits of evaluating different CGM metrics in patients with PBH.

Keywords

Post-bariatric hypoglycemia / continuous glucose monitoring / time in range / time below range

References

[1] Varma S,Schweitzer M,Brown TT.Weight regain in patients with symptoms of post-bariatric surgery hypoglycemia.Surg Obes Relat Dis2017;13:1728-34 PMCID:PMC5657438

[2] Hazlehurst J,Lobato CB.Society for endocrinology guidelines for the diagnosis and management of post-bariatric hypoglycaemia.Endocr Connect2024;13:e230285 PMCID:PMC11046333

[3] Scarpellini E,Karamanolis G.International consensus on the diagnosis and management of dumping syndrome.Nat Rev Endocrinol2020;16:448-66 PMCID:PMC7351708

[4] Diabetes Association Professional Practice Committee. 7. Diabetes technology: standards of care in diabetes-2024.Diabetes Care2024;47:S126-44 PMCID:PMC10725813

[5] Garg SK,Castorino K.Accuracy and safety of dexcom G7 continuous glucose monitoring in adults with diabetes.Diabetes Technol Ther2022;24:373-80 PMCID:PMC9208857

[6] Yoo JH.Advances in continuous glucose monitoring and integrated devices for management of diabetes with insulin-based therapy: improvement in glycemic control.Diabetes Metab J2023;47:27-41 PMCID:PMC9925143

[7] Ng ASC,Chee MWL.Effects of night-to-night variations in objectively measured sleep on blood glucose in healthy university students.Sleep2025;48:zsae224 PMCID:PMC11807882

[8] Matzka M,Lenk M.Accuracy of a continuous glucose monitoring system applied before, during, and after an intense leg-squat session with low- and high-carbohydrate availability in young adults without diabetes.Eur J Appl Physiol2024;124:3557-69 PMCID:PMC11569006

[9] Nolan T.The use of continuous glucose monitoring devices in non-diabetic adults … and other research.BMJ2024;385:q859

[10] Hasan M, Schwartz S, McKenna V, Ing R. An imbalance of pathophysiologic factors in late postprandial hypoglycemia post bariatric surgery: a narrative review.Obes Surg2023;33:2927-37

[11] Rossini G,Monte L.Postbariatric surgery hypoglycemia: nutritional, pharmacological and surgical perspectives.Diabetes Metab Res Rev2024;40:e3750

[12] Zheng H,Wang L,Gong F.Incidence and risk factors of post-metabolic and bariatric surgery hypoglycemia: a systematic review.Int J Obes2025;49:31-42

[13] Aydin Ö,de Jonge PA.Post-bariatric hypoglycemia: an impaired metabolic response to a meal.Obes Surg2024;34:3796-806 PMCID:PMC11481667

[14] Ramos-Levi AM,Matía-Martín P.Mixed meal tolerance test versus continuous glucose monitoring for an effective diagnosis of persistent post-bariatric hypoglycemia.J Clin Med2023;12:4295 PMCID:PMC10342744

[15] Mulla CM,Yee EU.Insulinoma after bariatric surgery: diagnostic dilemma and therapeutic approaches.Obes Surg2016;26:874-81 PMCID:PMC4814298

[16] Sjøbjerg A,Kramer S.[Severe hypoglycaemia due to insulinoma after gastric bypass surgery].Ugeskr Laeger2018;180

[17] Duff JM,Weber M.Delayed imaging presentation of a symptomatic insulinoma after bariatric surgery.J Gastrointest Surg2017;21:412-4

[18] Yu Y.Use of continuous glucose monitoring in patients following bariatric surgery: a scoping review.Obes Surg2023;33:2573-82

[19] Pasquel FJ,Khowaja A.A randomized controlled trial comparing glargine U300 and glargine U100 for the inpatient management of medicine and surgery patients with type 2 diabetes: glargine U300 hospital trial.Diabetes Care2020;43:1242-8 PMCID:PMC7411278

[20] Battelino T,Bergenstal RM.Clinical targets for continuous glucose monitoring data interpretation: recommendations from the international consensus on time in range.Diabetes Care2019;42:1593-603 PMCID:PMC6973648

[21] Monnier L,Owens DR.The application of simple metrics in the assessment of glycaemic variability.Diabetes Metab2018;44:313-9

[22] Gómez AM,Marin A.Different indexes of glycemic variability as identifiers of patients with risk of hypoglycemia in type 2 diabetes mellitus.J Diabetes Sci Technol2018;12:1007-15 PMCID:PMC6134628

[23] Lu J,Tu Y,Zhou J.Contribution of glycemic variability to hypoglycemia, and a new marker for diabetes remission after Roux-en-Y gastric bypass surgery.Surg Obes Relat Dis2022;18:666-73

[24] Lee D,Sheehan A,Mulla CM.Glycemic patterns are distinct in post-bariatric hypoglycemia after gastric bypass (PBH-RYGB).J Clin Endocrinol Metab2021;106:2291-303 PMCID:PMC8277212

[25] Rieck JH,Schlöricke E,Krause S.Is Sigstad’s score really capable of detecting post-surgical late dumping syndrome?.Langenbecks Arch Surg2024;409:94

[26] Arts J,Bisschops R.Efficacy of the long-acting repeatable formulation of the somatostatin analogue octreotide in postoperative dumping.Clin Gastroenterol Hepatol2009;7:432-7

[27] Kefurt R,Schindler K,Ludvik B.Hypoglycemia after Roux-En-Y gastric bypass: detection rates of continuous glucose monitoring (CGM) versus mixed meal test.Surg Obes Relat Dis2015;11:564-9

[28] Price B,Estrade A.Validity of continuous glucose monitoring for the diagnosis of dumping syndrome after metabolic surgery, in comparison to the oral glucose tolerance test.Obes Surg2024;34:4189-95

[29] der Kleij FG, Vecht J, Lamers CB, Masclee AA. Diagnostic value of dumping provocation in patients after gastric surgery.Scand J Gastroenterol1996;31:1162-6

[30] Lupoli R,Ciciola P,Pilone V.Continuous glucose monitoring in subjects undergoing bariatric surgery: diurnal and nocturnal glycemic patterns.Nutr Metab Cardiovasc Dis2020;30:1954-60

[31] Desouza C,Cheong B,Fonseca V.Association of hypoglycemia and cardiac ischemia: a study based on continuous monitoring.Diabetes Care2003;26:1485-9

[32] Kubota T,Ushigome E.Persistent postgastrectomy hypoglycemia unawareness in patients with gastric cancer unveiled by a prospective study.Ann Surg Open2022;3:e135 PMCID:PMC10431341

[33] Patience N,Cummings C.Medical nutrition therapy and other approaches to management of post-bariatric hypoglycemia: a team-based approach.Curr Obes Rep2022;11:277-86

[34] Kim K,Jang HC,Oh TJ.Glucose profiles assessed by intermittently scanned continuous glucose monitoring system during the perioperative period of metabolic surgery.Diabetes Metab J2022;46:713-21 PMCID:PMC9532174

[35] Hanaire H,Chauveau ME.Usefulness of continuous glucose monitoring for the diagnosis of hypoglycemia after a gastric bypass in a patient previously treated for type 2 diabetes.Obes Surg2010;20:126-9

[36] Suhl E,Mulla C.Medical nutrition therapy for post-bariatric hypoglycemia: practical insights.Surg Obes Relat Dis2017;13:888-96 PMCID:PMC5469688

[37] Cummings C,Sheehan A.Continuous glucose monitoring in patients with post-bariatric hypoglycaemia reduces hypoglycaemia and glycaemic variability.Diabetes Obes Metab2023;25:2191-202 PMCID:PMC10807851