Defining Clinical Characteristics of Individuals With and Without Post-Bariatric Hypoglycemia After Gastric Bypass

Context: Post-bariatric hypoglycemia (PBH) is a complication of bariatric surgery including Roux-en-Y gastric bypass (RYGB). It remains unclear why only some individuals develop PBH.

Objective: To identify clinical characteristics distinguishing post-RYGB individuals with PBH, versus without symptomatic hypoglycemia (RYGB non-hypo).

Design and setting: Cross-sectional observational study in academic referral centre. Adults 18-70, without current diabetes, were recruited into three groups: (1) PBH (n = 39); (2) RYGB non-hypo (n = 25); and (3) individuals without history of upper gastrointestinal surgery (n = 17). Outcome measures included between-group differences in medical history and medication use, and survey-based scores for hypoglycemia, dumping syndrome, and autonomic symptoms.

Results: PBH participants were 92% female, age 53.4 ± 11.9 y, BMI 31.2 ± 5.6 kg/m², versus RYGB non-hypo (100% female, age 53.2 ± 10.5 y, BMI 32.2 ± 8.0 kg/m²) and controls (65% female, age 44.5 ± 14.6 y, BMI 30.8 ± 6.3 kg/m²). 87% of PBH reported level 3 hypoglycemia, with emergency visits in 28% and vehicle accidents in 8%. Reduced hypoglycemia awareness was reported by 82%; 13%-17% were classified as unaware (modified Clarke/Gold scores). Preoperative hypoglycemia symptoms and family history were reported by 26% and 18% of PBH. PBH had significantly higher survey scores for hypoglycemia, dumping syndrome, and autonomic symptoms, and higher self-reported neuropathy, autonomic neuropathy, orthostatic hypotension, reflux esophagitis, intestinal dysmotility, and IBS (all p < 0.05 vs. RYGB non-hypo). Gabapentin and PPI use was more frequent in PBH.

Conclusion: High rates of IBS, dumping symptoms, and orthostatic hypotension suggest disordered autonomic regulation as a potential contributor to PBH. Self-reported preoperative symptoms and family history of hypoglycemia suggest possible preoperative differences in glucose metabolism in PBH.