Biliopancreatic diversion in nonobese patients with type 2 diabetes: impact and mechanisms

Context: Diabetes remission is frequent after biliopancreatic diversion (BPD) in morbidly obese patients with type 2 diabetes (T2D). Data, mechanisms, and clinical indications in nonobese T2D patients are scanty. Objective: The objective of the study was to assess remission and investigate insulin sensitivity and -cell function after BPD in nonobese patients with long-standing T2D. Design, Setting, and Patients: This was a clinical research study comparing 15 T2D patients (aged 55 1 years, duration of 16 2 years, body mass index of 28.3 0.6 kg/m2, glycosylated hemoglobin 8.6% 1.3%) with 15 gender-, age-, and body mass index-matched nondiabetic controls. Before surgery and 2 months and 1 year later, a 3-hour oral glucose tolerance test, a 5-hour mixed-meal test, and a 3-hour euglycemic clamp were performed. Intervention: The intervention included a BPD (distal gastrectomy, proximal ileum anastomosed to remaining stomach, biliopancreatic limb anastomosed to ileum 50 cm from the ileocecal valve). Results: Glycemia improved in all patients, but remission (glycosylated hemoglobin 6.5% and normal oral glucose tolerance test) occurred in 6 of 15 patients. Insulin resistance (19.8 0.8 mol min1 kgffm 1, P .001 vs 40.9 5.3 of controls) resolved already at 2 months (34.2 2.8) and was sustained at 1 year (34.7 1.6), although insulin-mediated suppression of endogenous glucose production remained impaired. In contrast, -cell glucose sensitivity (19 [12] pmolmin1 m2mM1 vs 96 [73] of controls, P .0001) rose (P .02) only to 31 [26] at 1 year and was lower in nonremitters (16 [18]) than remitters (46 [33]). Conclusions: In nonobese patients with long-standing T2D, BPD improves metabolic control but induces remission in only approximately 40% of patients. Peripheral insulin sensitivity is restored early after surgery and similarly in remitters and nonremitters, indicating a weight-independent effect of the operation. The initial extent of -cell incompetence is the main predictor of the metabolic outcome