Continuous glucose monitoring reveals high prevalence of hyperglycaemia in patients prior to pancreatic surgery: A pilot study

Aims: Patients with pancreatic tumours are at increased risk of diabetes mellitus (DM) and hyperglycaemia and a subsequent higher risk of developing postoperative complications. Continuous glucose monitoring (CGM) can be used to assess the prevalence of hyperglycaemia in pancreatic surgery patients. Methods: This single-centre observational pilot study (2023-2025) included 15 patients with DM type 2 or new onset DM (HbA1c ≥ 48 mmol/mol (6.5 %)) undergoing pancreatic surgery. Blinded CGM was performed for 2 weeks preoperatively and 2 weeks perioperatively. Primary outcome was time above range (TAR)(glucose > 10.0 mmol/l (180.2 mg/dl)) as a percentage of total CGM wear time. Secondary outcomes were time below and in range, glucose metrics, difference in preoperative HbA1c and patient satisfaction regarding CGM wear. Results: In total, 5 patients had new-onset DM, 6 suboptimal controlled DM (HbA1c ≥ 53 mmol/mol (7.0 %)) and 4 optimal controlled DM (HbA1c < 53 mmol/mol (7.0 %)) at baseline. Median preoperative TAR (>10.0 mmol/L (180.2 mg/dl)) was highest in the suboptimal controlled DM group (59.7 % [35.1-68.6]), compared to 7.9 % [0.9-19.4] in the optimal controlled and 16.7 % [7.7-23.7] in the new-onset DM group. Perioperatively, the optimal controlled DM group had the highest TAR (26.7 % [11.3-49.0]) while the new-onset and suboptimal controlled DM group had TARs of 4.6 % [1.2-9.6] and 16.3 % [11.5-23.4], respectively. Conclusions: Blinded CGM revealed frequent pre- and perioperative hyperglycaemia and high inter-individual variability in TAR among patients with (new-onset) DM undergoing pancreatic surgery. These findings support the need for stricter and more individualized glucose monitoring. This could optimize preoperative glucose management and thereby possibly reduce postoperative complications.