Background: The prevalence of post-bariatric surgery hypoglycemia (PBH) remains unclear due to diagnostic criteria variability, types of bariatric procedures and possible unawareness. Objective: To determine the frequency, pattern and severity of symptomatic and asymptomatic hypoglycemia in subjects post three different bariatric procedures performed >1 year before evaluation and a group of obese subjects before surgery. Design and Setting: Observational cohort study. Fifty-one consecutive patients participated: post Roux-en-Y gastric-bypass (RYGB) (n=16), post omega-loop gastric-bypass (OLGB) (n=12), post sleeve-gastrectomy (SG) (n=15), obese subjects before surgery (controls) (n=8). Hypoglycemic events (glucose ≤54 mg/dL) and severe hypoglycemia (glucose ≤40 mg/dL) were evaluated by symptoms' questionnaire, mixed-meal tolerance test (MMTT) and continuous glucose monitoring (CGM). Results: According to questionnaires, meal-related complaints were reported in 11 (26%) of the surgical group and in one control subject. During MMTT, 88%, 82% and 67% experienced hypoglycemia in RYGB, OMGB and SG groups, respectively, vs. none of the controls (P<0.001). Severe hypoglycemia occurred in 38%, 45% and 7% in RYGB, OMGB and SG groups, respectively (P=0.025), but only 10 of the total operated patients (24%) reported any symptoms. During CGM, fasting hypoglycemic events occurred more in RYGB and OLGB vs. SG group: 55%, 63% and 17% respectively (P=0.036). Conclusions: PBH is very common after RYGB, OMGB and SG and can be severe especially following bypass procedures. Our results show that hypoglycemia occurs not only postprandially but also in the fasting state, especially following bypass procedures. In most cases, there were no specific complaints, possibly leading to its underestimation.
Keywords: Bariatric surgery; OLGB; RYGB; SG; post-bariatric hypoglycemia.