Glycaemic variability(GV) is implicated in microvascular and macrovascular complications. We sought to compare the impact of Roux-en-Y gastric bypass(RYGB) versus Glucagon-like peptide-1 receptor agonist(GLP1-RA) therapy on GV as determined by retrospective continuous glucose monitoring(CGM).
In this prospective RCT of RYGB against best medical therapy (using GLP1-RA) in Asians within BMI 27-32 kg/m2 with suboptimally controlled Type 2 Diabetes (HbA1c>8%), CGM was performed at baseline and 6 weeks. GV parameters, calculated using online tool (easyGV©), include standard deviation (SD), mean amplitude of glycaemic excursions (MAGE), continuous overall net glycaemic action (CONGA), low and high blood glucose index (LBGI and HBGI) and glycaemic risk assessment diabetes equation (GRADE). HbA1c and weight were measured at baseline and 3 months.
Twenty patients were randomized to the medical and surgical arm (N=10 in each arm). Age (mean±SD) was 44.3±11.6 years and diabetes duration 5.8±2.9 years. There were no differences in baseline HbA1c, fasting plasma glucose, body mass index (BMI), diabetes duration and insulin use. Baseline CGM glycaemic profiles of mean glucose, SD, MAGE, CONGA, LBGI, HBGI and GRADE was similar between groups. At 6 weeks, both groups had reductions in mean glucose, SD, CONGA, HBGI and GRADE. For MAGE, the medical group resulted in greater reduction (6.6±1.4 to 4.4±1.6, p=0.03) compared to the surgical group (6.9±1.7 to 5.0±2.6,p=0.071). Notably, there was no difference in LBGI between the groups. Overall HbA1c and BMI reduction was greater in the surgical (HbA1c 9.8±1.4 to 6.1±0.4%, p<0.001; BMI 29.3±1.7 to 24.2±2.1, p=<0.001) than the medical group (9.0±0.9 to 6.8±0.9%, p<0.001; BMI 29.6±1.5 to 28.7±1.2, p=0.004); p=0.014 and p<0.001 for difference in HbA1c and BMI reductions respectively between surgical and medical groups.
In mildly obese Asian diabetes patients, although RYGB is superior to medical therapy in improving HbA1c and weight, medical therapy with GLP1-RA is equivalent to RYGB in reducing GV without increasing LBGI.