A 62-year-old man was diagnosed with type 2 diabetes complicated by an intraductal papillary mucinous neoplasm (IPMN) and underwent pancreatoduodenectomy (PD). In order to assess changes in his insulin secretion, insulin resistance, and glucose control pre- and postoperatively, 75 g OGTT and glucagon loading tests were performed before PD and one, three and six months after PD (Pre, Post 1, 3, 6). The insulinogenic index (I.I.), disposition index (D.I.),
ΔCPR, AUC (ins) /AUC (glu), HOMA-IR and Matsuda index were calculated based on the results of the 75 g OGTT and glucagon loading tests. In addition, the level of HbA1c was measured as a marker of glucose control. The I.I., D.I.,
ΔCPR, and AUC (ins) /AUC (glu) values were decreased by half at the Post 1 time point and continued to decrease until Post 6, thus indicating a decline in insulin secretion. Meanwhile, the HOMA-IR decreased from 3.5 (Pre) to 1.9 (Post 6) and the Matsuda index increased from 3.1 (Pre) to 5.2 (Post 6), indicating an improvement in insulin resistance. The HbA1c level was found to be worse at every postoperative time point. In conclusion, the possibility of a decrease in insulin secretion and defects in glucose control should be taken into account in patients with type 2 diabetes accompanied by IPMN who undergo PD.
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