Utility of continuous glucose monitoring following gastrectomy

Background Glucose fluctuation after gastrectomy represented by dumping syndrome is a well-known post-gastrectomy syndrome that negatively impacts patient quality of life. However, the current methods of post-gastrectomy glucose monitoring do not comprehensively capture the postoperative blood glucose fluctuations that characterize this. Methods We used a continuous glucose monitoring (CGM) system to document the glycemic profiles of patients undergoing gastrectomy and compared these between patients undergoing distal gastrectomy (DG) and total gastrectomy (TG). To evaluate post-gastrectomy syndromes, including dumping syndrome, we used the Post-gastrectomy Syndrome Assessment Scale 37-item questionnaire. The glycemic profiles were also compared using this tool. Results We studied 57 patients who had undergone DG and 13 who had undergone TG between September 2017 and September 2019. Our results revealed larger diurnal glycemic variability and longer periods of nocturnal hypoglycemia after gastrectomy. The dumping score was worse in the TG than in the DG group (TG 2.4 ± 1.4 vs. DG 1.3 ± 1.2, P = 0.0061). Importantly, 30 of 57 DG patients (52.6%) and 5 of 13 TG patients (38.5%) experienced postprandial hypoglycemia following hyperglycemia without hypoglycemic symptoms. There was no correlation between the dumping symptom score and glycemic variability ( ρ = 0.0545, P = 0.6662). Conclusions CGM demonstrated diurnal glycemic variability and nocturnal hypoglycemia in patients undergoing gastrectomy. Because some hypoglycemic patients did not develop symptoms and glycemic variability was not necessarily associated with dumping symptom, dumping syndrome must only partially explain the postoperative glucose fluctuations.