Long-Term Outcomes of Biliopancreatic Diversion on Glycemic Control, Insulin Sensitivity and Beta Cell Function

Background: We aimed to assess the long-term outcomes of biliopancreatic diversion (BPD) surgery on glycemic control, insulin sensitivity (IS), and beta cell function using complementary oral and intravenous dynamic tests.

Methods: A total of 57 women were divided into three groups: 19 lean, 18 obese (both groups with normal glucose tolerance (NGT)), and 20 obese with type 2 diabetes who underwent BPD and were reassessed 12 months after the procedure. OGTTs and hyperglycemic clamps (HG) were performed. Mathematical modeling was used to analyze IS, beta cell function, and delayed time of beta cell response. The basal, dynamic (first phase/steps of insulin secretion), and static (second phase/steps of insulin secretion) disposition indexes were calculated.

Results: After surgery, the patients exhibited improvements in glycemic control and 15 patients achieved diabetes remission. The surgical patients demonstrated normalized IS in OGGT and HG tests compared to the control groups. The basal beta cell function was improved but remained impaired compared to the Lean NGT group. The stimulated beta cell function parameters showed marked improvements regarding the intravenous stimulus and the second phase/distal steps of insulin secretion. The delay time markedly decreased and became normalized in both dynamic tests.

Conclusions: The common physiopathology features of type 2 diabetes, i.e., impaired IS and beta cell dysfunction, were demonstrated to be primarily functional and were likely to be reversible to some degree after the BPD. The marked long-term improvement in glycemic control after BPD was closely related to IS improvement and mainly by the recovery of several beta cell physiological features.