Pancreatic beta cell function is preserved in the short term in patients with type 2 diabetes undergoing non-urgent surgery

BACKGROUND: Type 2 diabetes mellitus (T2DM) is a progressive condition influenced by many factors. Surgery usually produces hyperglycemia in the postoperative period, which leads to adverse clinical outcomes. Possible consequences of surgery on beta cell reserve have not been explored. The aim of this study was to assess the effect of surgery on the beta cell function of patients with T2DM undergoing non-urgent surgery. METHODS: We performed a prospective observational study on the population of patients with T2DM scheduled for surgery in a tertiary level hospital. After adequate wash-out periods for antidiabetic medications, two blood samples were collected: one fasting and the other one six minutes after an intravenous stimulation with glucagon. Glucose, insulin and C-peptide concentrations were measured. This determination was repeated about a month after surgery. RESULTS: We included 42 patients with the following characteristics: 47.6% males, average HbA1(c) 7%, average time from T2DM diagnosis 7.3 years and average age 62.1 years. Intravenous glucagon produced a significant increase in C-peptide after six minutes in both the presurgical (C-peptide values: basal 2.97 ng/mL; after glucagon 5.53 ng/mL) and the postsurgical (C-peptide values: basal 3.12 ng/mL; after glucagon 5.67 ng/mL) periods (mean difference 2.56 ng/mL and 2.55 ng/mL respectively, P<0.001). However, C-peptide increase after glucagon was not different between the presurgical and the postsurgical periods (2.56 ng/mL vs. 2.55 ng/mL, P>0.05). CONCLUSIONS: The pancreatic beta reserve of patients with T2DM was not affected a month after the non-urgent surgery. The direct measurement of pancreatic function by dynamic assessment with glucagon did not change, nor did we find alterations in the indirect calculation of insulin secretion using the HOMA-B. None of these parameters reached statistical significance. Non-urgent surgical procedures included in our study are safe for patients with short lasting, properly controlled T2DM, from the point of view of glucose metabolism assessed by pancreatic insulin secretion. We can consider non-urgent surgical procedures safe from the point of view of the preservation of the pancreatic reserve in patients with T2DM. A sharp deterioration of metabolic control is not expectable in the short term for these patients, which represent a large proportion of the population undergoing surgery in modern hospitals.