Background: Roux-en-Y Gastric Bypass (RYGB) and Sleeve Gastrectomy are two widely used bariatric procedures. Longitudinal data have shown similar efficacy in terms of sustained weight loss and diabetes remission in obese patients with type 2 diabetes. Altered glucose dynamics with increased glycaemic variability and the occurrence of hypoglycaemia are common post-bariatric surgery.
Aim: To compare the glycaemic variability and incidence of hypoglycaemia between patients who had undergone RYGB or Sleeve Gastrectomy.
Subjects and Methods: We compared retrospectively seven patients who had undergone RYGB and seven patients who had undergone Sleeve Gastrectomy at 1260 months post-surgery. Glycaemic variability was assessed by using the Dexcom G6 Continuous Glucose Monitoring system for 710 days on each occasion. The CGM metrics analysed included mean glucose, %CV, CONGA, MAGE and ADDR. The %Time in Range (TIR) and the incidence of hypoglycaemia were also compared between the groups.
Results: There was no significant difference between the weight, HbA1c or mean glucose between the two groups at the time of the study. Despite the fact that the %TIR (3.9 10.0 mmol/l) did not differ between the two groups, there was significantly increased glycaemic variability as evidenced by the higher CONGA, MAGE, ADDR and %CV in the RYGB group compared to the Sleeve Gastrectomy (P<0.01). The incidence of hypoglycaemia assessed by %TIR (<3.9 mmol/l) and %TIR (<3.0 mmol/l) was also greater in the RYGB group (P=0.018 and P=0.019 respectively).
Conclusions: Despite similar results in terms of weight and glycaemic control as assessed by standard metrics of mean glucose and HbA1c, there is a difference in the glucose profiles as illustrated by the increased glycaemic variability and incidence of hypoglycaemia after RYGB in comparison to Sleeve Gastrectomy. Patients who undergo Sleeve Gastrectomy may be less vulnerable to post-bariatric hypoglycaemia.