Introduction: About 20% of patients operated with Roux-en-Y gastric bypass (RYGBP) experience poor long-term weight result. This study compared levels of leptin and gut hormones in long-term weight responders with non-responders after RYGBP. In a subgroup analysis, hormone levels were assessed in T2DM (type 2 diabetes mellitus) and normoglycemic participants.
Methods: Insulin, glucose, leptin, acyl-ghrelin, total PYY, active GLP-1, and GIP were measured during an oral glucose tolerance test (OGTT) in post-RYGBP subjects: 22 non-responders (BMI 40.6 ± 6.0 kg/m2 after an excess BMI loss [EBMIL] of 26.0 ± 15.9%) and 18 responders (BMI 29.5 ± 3.5 kg/m2 after an EBMIL of 74.9 ± 18.2%). Subjects were matched for preoperative age, BMI, and years of follow-up. Measures of glucose homeostasis were calculated, and body composition was measured.
Results: Fat mass-adjusted fasting leptin correlated negatively with %EBMIL (r = - 0.57, p < 0.01). Non-responders presented higher levels of leptin during the OGTT. Leptin decreased and ghrelin returned to baseline levels earlier in non-responders. Despite having higher insulin resistance than responders, non-responders demonstrated similar OGTT responses of GLP-1, GIP, and PYY. T2DM participants demonstrated lower GLP-1 levels than normoglycemic participants of similar weight.
Conclusion: Fasting leptin is associated with weight result after RYGBP, and hormonal responses to a glucose oral load might work towards promoting obesity in long-term non-responders after RYGBP. Poor long-term weight result and glycemic status after RYGBP are each associated with differences in peptide hormone levels.
Keywords: Gastric bypass; Incretins; Leptin; Long-term results; Weight loss.