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

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.