Glycemic Patterns Are Distinct In Post-Bariatric Hypoglycemia After Gastric Bypass (Pbh-Rygb)

Context: Severe hypoglycemia with neuroglycopenia, termed post-bariatric hypoglycemia (PBH). typically occurs postprandially, but it is also reported after activity or mid-nocturnally.Objective: To quantify glycemia, glycemic variability, and magnitude/duration of low sensor glucose (SG) values in patients with PBH after Roux-en-Y gastric bypass (PBH-RYGB).Methods: This retrospective analysis of data from an academic medical center included individuals with PBH-RYGB (n=40), reactive hypoglycemia without gastrointestinal surgery (Non-Surg Hypo, n=20), prediabetes (Pre-DM, n=14), newly diagnosed T2D (n=5), and healthy controls (HC, n=38). Masked continuous glucose monitoring (Dexcom G4) was used to assess patterns over 24 hours, daytime (6 am-midnight) and nighttime (midnight-6 am). Pre-specified measures included mean and median SG, variability, and percent time at thresholds of sensor glucose.Results: Mean and median SG were similar for PBH-RYGB and HC (mean: 99.818.6 vs 96.9 +/- 10.2 mg/dL; median: 93.0 +/- 14.8 vs 94.5 +/- 7.4 mg/dL). PBH-RYGB had a higher coefficient of variation (27.3 +/- 6.8 vs 17.9 +/- 2.4%, P<0.0001) and range (154.5 +/- 50.4 vs 112.0 +/- 26.7 mg/dL, P<0.0001). Nadir was lowest in PBH-RYGB (42.5 +/- 3.7 vs HC 49.0 +/- 11.9 mg/dL, P=0.0046), with >2-fold greater time with SG<70 mg/dL vs HC (7.7 +/- 8.4 vs 3.2 +/- 4.1%, P=0.0013); these differences were greater at night (12.6 +/- 16.9 vs 1.0 +/- 1.5%, P<0.0001). Non-Surg Hypo also had 4-fold greater time with SG<70 at night vs HC (SG<70: 4.0 +/- 5.9% vs 1.0 +/- 1.5%), but glycemic variability was not increased.Conclusion: Patients with PBH-RYGB experience higher glycemic variability and frequency of SG<70 compared to HC, especially at night. These data suggest that additional pathophysiologic mechanisms beyond prandial changes contribute to PBH.