The incidence of DM varies between 20% and 50% of patients who undergo PD, independently of pre-existing DM.[19] Recent reports have indicated that glucose metabolism improves after PD.[4,9–11] Ohtsuka et al[8] performed an oral glucose tolerance test (OGTT) in 17 patients with periampullary tumors and showed that postoperative levels of plasma glucose and insulin, as well as IR, improved, although β-cell function did not change after surgery. This evidence concerns the gene INS and diabetes mellitus.