Abstract: Objective:To investigate the clinical efficacy of the laparoscopic RouxenY gastric bypass (LRYGB) and metformin in the treatment of obese patients with type 2 diabetes mellitus, and influencing factors of remission rate of diabetes.
Methods:The casecontrol study was conducted. The clinical data of 172 obese patients with type 2 diabetes mellitus who were admitted to the First People′s Hospital of Shangqiu (43 patients) and the First Affiliated Hospital of Sun Yatsen University (129 patients) from June 2010 to June 2015 were collected. Of 172 patients, 82 undergoing LRYGB were allocated into the group A and 90 taking oral metformin were allocated into the group B. Observation indicators: (1) followup situations; (2) comparison of metabolic indices after treatment between the 2 groups; (3) influencing factors analysis of remission rate of diabetes in patients undergoing LRYGB; (4) influencing factors analysis of remission rate of diabetes in patients taking oral metformin. Followup using outpatient examination and telephone interview was performed to detect occurrence of treatmentrelated complications up to January 2017, and metabolic indices were measured regularly. Measurement data with normal distribution were represented as ±s and comparison between groups was analyzed using the independentsample t test. Repeated measurement data were analyzed by the repeated measures ANOVA. Comparisons of count data were evaluated by the chisquare test. The univariate analysis and multivariate analysis were respectively done using the chisquare test and Logistic regression model.
Results:(1) Followup situations: 172 patients were followed up after treatment for 19-43 months, with a median time of 28 months. During the followup, 5 patients complicated with mild diarrhea and 1 complicated with iron deficiency anemia at 1 year postoperatively were improved by symptomatic treatment in the group A, and there was no treatmentrelated complications in the group B. (2) Comparison of metabolic indices after treatment between 2 groups: body mass, BMI, 2hour postprandial blood glucose (2HPBG), 2hour postprandial serum Cpeptide, glycosylated hemoglobin (GHb), fasting insulin, 2hour postprandial insulin (2HPI), lowdensity lipoprotein (LDL) and cases with hypertension in the group A were (89±6)kg, (31.5±2.0)kg/m2, (19.4±3.9)mmol/L, (3.52±0.32)μg/L, 15.7%±5.3%, (8.0±1.4)uIU/L, (20.6±2.5)uIU/L, (3.7±1.3)mmol/L, 24 before LRYGB and (77±16)kg, (24.2±2.9)kg/m2, (10.6±2.6)mmol/L, (7.19±2.23)μg/L, 5.3%±4.5%, (9.2± 4.3)uIU/L, (28.3±2.9)uIU/L, (2.2±2.1)mmol/L, 9 after LRYGB, respectively, with statistically significant differences between preoperative and postoperative indicators (F=2.112, 3.026, 1.253, 2.107, 1.257, 3.473, 1.223, 2.584, x²=8.540, P<0.05). Fasting blood glucose, 2HPBG, fasting serum Cpeptide, 2hour postprandial serum Cpeptide, GHb, fasting insulin and 2HPI in the group B were (11.3±2.5)mmol/L, (18.5±4.4)mmol/L, (1.54±0.33)μg/L, (3.57±0.91)μg/L, 17.5%±8.0%, (8.2±1.3)uIU/L, (21.2±2.6)uIU/L before taking oral metformin and (6.6±1.1)mmol/L,(10.2±2.8)mmol/L, (3.52±1.34)μg/L, (7.68± 1.94)μg/L, 5.4%±2.1%, (9.6±3.9)uIU/L, (30.3±3.1)uIU/L after taking oral metformin, respectively, with statistically significant differences between before and after taking oral metformin (F=1.245, 3.224, 3.127, 2.064, 3.672, 2.074, 1.137, P<0.05). Remission rate of diabetes and excess weight loss (EWL) in patients after treatment were 14.6%, 80%±15% in the group A and 11.1%, 60%±10% in the group B, respectively. There were statistically significant differences in body mass, BMI and EWL after treatment between the 2 groups (t=1.973, 2.326, 2.347, P<0.05), and no statistically significant difference in remission rate of diabetes between the 2 groups (x²=0.477, P>0.05). (3) Influencing factors analysis of remission rate of diabetes in patients undergoing LRYGB: the results of univariate analysis showed that BMI, diabetes duration and LDL were factors affecting remission rate of diabetes in patients undergoing LRYGB, with statistically significant differences (x²=11.267, 9.519, 5.567, P<0.05). The results of multivariate analysis showed that diabetes duration< 10 years was an independent factor affecting good remission rate of diabetes in patients undergoing LRYGB, with statistically significant differences ［OR=2.202, 95% confidence interval (CI):1.418-3.420, P<0.05］. (4) Influencing factors analysis of remission rate of diabetes in patients taking oral metformin: the results of univariate analysis showed that diabetes duration, GHb and LDL were factors affecting remission rate of diabetes in patients taking oral metformin, with statistically significant differences (x²=6.306, 7.758, 4.652, P<0.05). The results of multivariate analysis showed that GHb <15.0% was an independent factor affecting good remission rate of diabetes in patients taking oral metformin, with statistically significant differences (OR=3.167, 95%CI: 1.586-6.325, P<0.05).
Conclusions:LRYGB and oral metformin in the treatment of obese patients with type 2 diabetes mellitus are safe and effective, showing an equivalent remission rate of diabetes, and LRYGB had an advantage of weight loss. Diabetes duration <10 years and GHb <15.0% are respectively independent factors affecting good remission rate of diabetes in patients undergoing LRYGB and taking oral metformin.