Gastrointestinal metabolic surgery for the treatment of type 2 diabetes mellitus

Table 1 Randomized controlled trials that directly compared the effectiveness of bariatric procedures with medical management for the treatment of type 2 diabetes

Trial	Dixon et al[57]	Schauer et al[34]	Mingrone et al[105]	Ikramuddin et al[58]
Intervention arms	LAGB; standard medical management	RYGB; LSG; medical management	RYGB; BPD; medical management	RYGB with medical management; medical management
Follow-up duration (yr)	2	1	2	1
Baseline characteristics
n	60	150	60	120
Mean BMI (kg/m2)	37 (30-40)	36 (27-43)	45 (35-60)	34 (30-40)
Duration of T2DM (yr)	< 2	> 8	6	9
Mean HbA1c	7.8%	9.2%	8.7%	9.6%
Primary end-point	FBG < 126 mg/dL with HbA1c < 6.2% without pharmacotherapy	HbA1c < 6% with or without pharmacotherapy	FBG < 100 mg/dL with HbA1c < 6.5% without pharmacotherapy	CV risk reduction with HbA1c < 7% with LDL cholesterol < 100 mg/dL and systolic BP < 130 mmHg
End results
Diabetes remission	LAGB 73%; medical arm 13%	RYGB 42%; LSG 37%; medical arm 12%	BPD 95%; RYGB 75%; medical arm 0%	RYGB 75%; medical arm 32%
Mean HbA1c	LAGB 6.0%; medical arm 7.2%	RYGB 6.4%; LSG 6.6%; medical arm 7.5%	BPD 4.9%; RYGB 6.3%; medical arm 7.7%	RYGB 6.3%; medical arm 7.8%
Mean BMI (kg/m2)	LAGB 29.5; medical arm 36.6	RYGB 26.8; LSG 27.2; medical arm 34.4	BPD 29.1; RYGB 29.3; medical arm 43.1	RYGB 25.8 medical arm 31.6
Mean excess weight loss	LAGB 62%; medical arm 4.3%	RYGB 88%; LSG 81%; medical arm 13%	BPD 69%; RYGB 68%; medical arm 9%	1RYGB 26.1 medical arm 7.9%
Major surgical complications	2 revision surgeries (6.7%) due to pouch enlargement; 1 required band removal due to persistent regurgitation	4 re-operations (4.0%) due to intra-abdominal hematoma, vomiting, cholecystectomy, and feeding access after gastric leak	2 re-operations (5.0%) due to incisional hernia and bowel obstruction. More nutritional risk in BPD than in RYGB	2 re-operations (3.3%) due to anastomotic leak. Surgical group had 50% more serious events with greater nutritional deficiency than medical arm
Mortality	Nil	Nil	Nil	Nil
Comment	This trial involved patients with early (< 2 yr) diabetes of mild severity (HbA1c < 7.8%), but only 22% of patients had BMI 30-35. This trial supported early surgical intervention for early obese T2DM	This trial involved patients with more advanced diabetes (> 8 years and HbA1c 9.2%), with 34% of patients having BMI < 35. This trial supported surgical intervention in more severe T2DM	This trial involved severely obese diabetic patients and showed the greater effectiveness of bariatric surgery over medical therapy in poorly controlled T2DM	This trial showed the potential benefits and risks of adding RYGB to the best medical therapy in achieving therapeutic goals for diabetes (49% vs 19%). This trial had a higher proportion of BMI 30-35 (59%)

¹Mean weight loss. T2DM: Type 2 diabetes mellitus; BMI: Body mass index; LAGB: Laparoscopic adjusted gastric banding; RYGB: Roux-en-Y gastric bypass; LSG: Laparoscopic sleeve gastrectomy; BPD: Bilio-pancreatic diversion; FBG: Fasting blood glucose; HbA1c: Glycosylated hemoglobin; LDL: Low density lipoprotein; CV: Cardiovascular.