Metabolic surgery: A paradigm shift in type 2 diabetes management

Table 1 Major randomised controlled trials reporting effects of metabolic surgical procedure on type 2 diabetes mellitus

RCT	Study details	Outcome	Diabetes remission
Dixon et al[8]	Un-blinded RCT. N = 60 Obese patients with recent onset T2DM Conventional therapy vs LAGB Follow-up: 2 yr	Weight loss –1.7% ± 5.2% in conventional group and –20.7% ± 8.6% in the surgical group	73% in surgical group 13% in conventional group (Remission of T2DM defined as FBS < 7.0 mmol/L and HbA1c < 6.2%)
Mingrone et al[7]	Single centre non-blinded RCT. N = 60. Severely obese patients. T2DM of at least 5 yr duration and HbA1c > 7.0%. Conventional medical therapy vs RYGB or BPD Follow-up: 2 yr	Weight loss −4.7% ± 6.3% with medical therapy, −33.3% ± 7.8% with RYGB and −33.8% ± 10.1% with BPD	75% in RYGB group; 95% in BPD group. None in the conventional group (Remission defined as FBS < 5.6 mmol/L and HbA1c < 6.5%)
Schauer et al[9]	Single centre non-blinded RCT in obese uncontrolled T2DM. N = 150 Intensive medical therapy vs RYGB or SG Follow-up: 12 mo	Weight loss –5.4 ± 8.0 kg in medical therapy group, -29.4 ± 9.0 kg in RYGB group and –25.1 ± 8.5 kg in SG group	12% medical therapy group 42% in RYGB group 37% SG group (Remission/primary outcome defined as HbA1c of 6% or less)
Ikramuddin et al[10]	Un-blinded RCT in obese T2DM with HbA1c over 8% with average duration of 9 yr. N = 120 Intensive medical therapy vs RYGB Follow-up: 12 mo	Difference in weight loss between surgical and medical group –17.1 ± 5.6 kg. % weight change in medical vs Surgical group –7.9 ± 2 vs–26 ± 2	75% RYGB group 32% in medical group (Remission defined as HbA1c < 7%)
Liang et al[11]	RCT in obese T2DM. N = 108. RYGB compared with standard care with or without Exenatide therapy Follow-up: 12 mo	Reduction in BMI (kg/m2) in standard vs Exenatide vs RYGB: –0.56 ± 1.66 vs–3.44 ± 1.21 vs–5.97 ± 0.91	90% in RYGB group None in patients receiving standard care with or without Exenatide (Remission defined as HbA1c < 6.5%)

RCTs: Randomised controlled trials; T2DM: Type 2 diabetes mellitus; N: Number of subjects; LAGB: Laparoscopic gastric banding; FBS: Fasting blood sugar; RYGB: Roux-en-Y gastric bypass; SG: Sleeve gastrectomy; BPD: Bilio-pancreatic diversion.

Table 2 The mean changes in body mass index and haemoglobin A1c achieved with different gastric bypass procedures

Bariatric	Body mass index (kg/m2)			HbA1c (%)
procedure	Pre-surgery	Post-surgery	Mean reduction (95%CI)	Pre-surgery	Post-surgery	Mean reduction (95%CI)
AGB	37	29.5	7.5 (5.9-9.1)	7.8	6	1.8 (1.3-2.3)
SG	41.3	28.3	13.0 (10.1-15.9)	7.9	6	1.9 (1.0-2.8)
RYGB	34.6	25.8	8.8 (5.2-12.4)	8.2	6.1	2.1 (1.3-2.9)
BPD	50.5	34.6	15.9 (11.8-20.0)	8	5.2	2.8 (2.1-3.5)

AGB: Adjustable gastric banding; SG: Sleeve gastrectomy; RYGB: Roux-en-Y gastric bypass; BPD: Bilio-pancreatic diversion; HbA1c: Haemoglobin A1c.