Continuous glucose monitoring systems are increasingly used to detect and manage postbariatric hypoglycemia (PBH), although data on their accuracy in this population remain limited. A retrospective analysis published in Diabetes Care evaluated the accuracy of a real-time continuous glucose monitoring (rtCGM) system in adults with PBH after Roux-en-Y gastric bypass (RYGB).

The study included 70 individuals and analyzed 1,822 paired sensor and venous whole-blood glucose (BG) measurements obtained during a standardized solid mixed-meal test. Glucose excursions were assessed during stable and dynamic postmeal periods, with dynamic phases stratified by the magnitude and direction of the rate of change. A secondary analysis estimated sensor lag time and evaluated factors influencing accuracy.

Mean absolute relative difference was 9.6% during stable conditions and 16.4% during dynamic periods. After the meal test, 67.6% of sensor values were within ±15% or 15 mg/dL of reference BG, 78.0% within ±20% or 20 mg/dL, and 90.8% within ±30% or 30 mg/dL. Accuracy was lower during rapid glucose declines exceeding 1.5 mg/dL/min. At plasma glucose nadir, sensor values were higher than reference BG, with a mean bias of 8.2 mg/dL. The estimated plasma-interstitium lag time was 9.8 minutes. No participant or sensor characteristic significantly affected accuracy.

These findings indicate that meal-induced glucose dynamics, particularly rapid declines, are associated with reduced continuous glucose monitoring accuracy in PBH and should be considered during evaluation and management.