GI surgery (i.e., RYGB, LAGB, or BPD) should be considered for the treatment of T2DM in acceptable surgical candidates with BMI ≥35 kg/m2 who are inadequately controlled by lifestyle and medical therapy (A).a A surgical approach may also be appropriate as a non-primary alternative to treat inadequately controlled T2DM in suitable surgical candidates with mild-to-moderate obesity (BMI 30–35 kg/m2) (B). RYGB may be an appropriate surgical option for diabetes treatment in this patient population (C)
Although novel GI surgical techniques (e.g., DJB, IT, SG, endoluminal sleeves) show promising results for the treatment of T2DM in early clinical studies, they should currently be used only in the context of IRB-approved and IRB-registered trials (A)
To improve quality of medical evidence, the development of standards for measuring clinical and physiological outcomes of surgical treatment for T2DM is a high priority (A)
Randomized controlled trials are strongly encouraged to assess the utility of GI surgery to treat T2DM (A). In patients with BMI <35 kg/m2, determining the appropriate use of GI surgery for the treatment of T2DM is an important research priority (A). Controlled clinical trials in these patients should be performed to determine the safety and efficacy of GI metabolic surgery (A) as well as to identify parameters other than BMI as criteria for appropriate patient selection (A). Development of a standard registry/database is a high priority for research in this area (A). In addition to clinical trials, animal studies can provide useful information about the efficacy and mechanisms of GI metabolic surgery to treat T2DM (A)
The study of GI metabolic surgery provides valuable, new opportunities for investigating contributions of the GI tract to glucose homeostasis and the pathophysiological mechanisms of T2DM (A). Available data from animal and clinical studies suggest that weight loss alone explains diabetes control after LAGB (A). In contrast, intestinal bypass procedures such as RYGB, BPD, and DJB appear to engage additional antidiabetes mechanisms beyond those related to reduced food intake and body weight (A). Furthermore, anatomic modifications of various regions of the GI tract ameliorate T2DM through distinct physiological mechanisms (B). Collaboration among endocrinologists, surgeons, and basic scientists should be encouraged to facilitate greater understanding of GI mechanisms of metabolic regulation and to allow use of these insights to improve the treatment of T2DM (A)
The establishment of a multidisciplinary task force to guide the study and development of diabetes surgery is a high priority. This task force should include endocrinologists, surgeons, clinical and basic investigators, and bioethicists, among others (A)
Bariatric surgery is an appropriate treatment for people with T2DM and obesity (BMI equal to or greater than 35 kg/m2) not achieving recommended treatment targets with medical therapies, especially where there are other obesity-related comorbidities. Under some circumstances, people with a BMI of 30–35 kg/m2 should be eligible for surgery |
It is up to each health system to determine whether bariatric surgery with its support services is economically appropriate |
Surgery should be considered as complementary to medical therapies to reduce microvascular and cardiovascular risk |
Patients should be assessed and managed by experienced multidisciplinary teams |
Glycemic control should be optimized perioperatively and should be closely monitored after surgery |
Ongoing and long-term nutritional supplementation and support must be provided to patients after surgery |
Apart from conventional procedures now in use, new techniques and devices should be explored in research settings only. Conventional procedures should be standardized. Other techniques, variations, and novel devices can be introduced when supported by an evidence base |
Procedure selection requires appropriate assessment of risk versus benefit of each operation as part of the process for selecting the surgical treatment options for an individual patient |
New bariatric procedures require robust assessment for their efficacy, safety, and durability, using similar principles to those for assessing new drug therapies and having regards to the benefits and risks of established therapy |
Regional surgical expertise, multidisciplinary team experience, and documented quality outcomes are important factors in the regional choice of bariatric procedures |
There should be a minimal accepted data set for pre-surgery and follow-up to allow audit of clinical programs, for example, HbA1c, fasting glucose and insulin, BMI, waist circumference, retinopathy status (recent eye examination), nephropathy (e.g., test for microalbuminuria within previous year), liver function tests, lipid profile, blood pressure measurement, foot exam (recent), and documentation of medications (glycemia, lipids, and hypertension); these should be used preoperatively: fasting C-peptide where available and autoantibody status (e.g., anti-GAD) where available |
All longitudinal studies should include quality of life as one of the outcomes |
It should be recognized that a prolonged period of normalization of glycemic control has benefit even if there is eventual relapse |
Currently, metabolic operations are considered an appropriate treatment for diabetic patients with body mass index (BMI) ≥ 35 kg/m2, especially those with other weight-related comorbidities such as hypertension and dyslipidemia, who are acceptable surgical candidates and have not responded adequately to nonsurgical management (i.e., glycated hemoglobin >7 % despite of conventional therapies). Since T2DM has a progressive course and severely obese diabetic patients are often refractory to conventional therapies secondary to severe insulin resistance, metabolic operations should be considered earlier in the treatment plan of diabetics [1–4]. According to the International Diabetes Federation, for Asian and some other ethnicities of increased risk, BMI action points may be reduced by 2.5 kg/m2 [1].
Standard Metabolic Procedures
The International Diabetes Federation places emphasis on performing metabolic operations in high-volume centers with multidisciplinary teams that are experienced in the management of obesity and diabetes. Surgeons must have undertaken relevant supervised training and attained specific clinical expertise for each surgical procedure [1].
The International Diabetes Federation has considered Roux-en-Y gastric bypass (RYGB), laparoscopic adjustable gastric banding (LAGB), sleeve gastrectomy (SG), biliopancreatic diversion (BPD), and the duodenal switch variant (BPD-DS) as currently accepted metabolic operations. Vertical banded gastroplasty (VBG) has fallen out of favor because of suboptimal long-term results. The first two procedures have been considered acceptable procedures in adolescents [1]. Of note, variations in the steps of each procedure are associated with dissimilar metabolic responses. For example, the size of the gastric pouch and gastrojejunostomy anastomosis, placement of a band around the anastomosis, and the length of the limbs may affect metabolic outcomes after RYGB [8].
The morbidity and mortality rate associated with metabolic operations is generally low. It has been shown that the laparoscopic approach is associated with fewer postoperative complications than the open approach, most notably the risk of wound infection and incisional hernia [3, 4, 9]. Robotic and single incision laparoscopic approaches are considered emerging platforms in the field of bariatric and metabolic surgery with benefits and limitations that are not yet clear.
Outcomes
Several observational and nonrandomized trials have demonstrated marked and sustained improvement in T2DM in both morbidly obese and less obese patients following metabolic operations. Since the studies in this field are heterogeneous with inconsistent methodologies for inclusion criteria (e.g., duration or severity of T2DM), measurement of outcomes, definition of remission, and direct comparison of results are difficult [3–6, 10].
Meta-analyses involving more than 100 studies have shown an 80 % early complete remission of T2DM and 75 % persistent remission more than 2 years after surgery. The beneficial effects on hypertension and dyslipidemia were also impressive (Table 29.3) [11, 12].
Table 29.3
Efficacy of standard metabolic operations according to the two meta-analyses
Total (%) | LAGB (%) | RYGB (%) | BPD (%) | |
|---|---|---|---|---|
Resolution of type 2 diabetes | 78 | 57 | 80 | 95 |
Resolution of hypertension | 62 | 43 | 68 | 83 |
Improvement of dyslipidemia | 79 | 59 | 97 | 99 |
% EBWL (long term) | 59 | 49 | 63 | 74 |
High Level of Evidence Studies Comparing Metabolic Surgery Versus Conventional Therapy for T2DM
A growing body of evidence derived from recent randomized controlled trials has demonstrated superiority of bariatric surgery over conventional medical therapy for management of T2DM (Table 29.4) [13–15].
Table 29.4
High level of evidence studies on metabolic surgery versus conventional medical therapy for type 2 diabetes
Author | Journal | Year | Study type | BMI (kg/m2) | Follow-up (years) | Definition of end pointa | Procedure | Surgical group (n) | Medical group (n) | Proportion with end point in surgical group (%) | Proportion with end point in medical group (%) | P value | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schauer et al. [13] | N Engl J Med | 2012 | RCT | 27–43 | 1 | HbA1c ≤6 % | RYGB | 50 | 41 | 42 | 0 | <0.001 | ||
SG | 49 | 41 | 27 | 0 | <0.001 | |||||||||
Mingrone et al. [14] | N Engl J Med | 2012 | RCT | ≥35 | 2 | HbA1c <6.5 % | RYGB | 19 | 18 | 75 | 0 | <0.001 | ||
BPD | 19 | 18 | 95 | 0 | <0.001 | |||||||||
Dixon et al. [15] | JAMA | 2008 | RCT | 30–40 | 2 | HbA1c <6.2 % | LAGB | 30 | 30 | 73 | 13 | <0.001 | ||
Sjöström et al. [16] | N Engl J Med | 2004 | NRCT | ≥34 (M) ≥38 (F) | 2 | FPG <126 mg/dL | RYGB, LAGB, VBG | 342 | 248 | 72 | 21 | <0.001 | ||
10 | 118 | 84 | 36 | 13 | <0.001 | |||||||||
Adams et al. [17] | Obesity | 2010 | NRCT | ≥35 | 2 | FPG <126 mg/dL | RYGB | 61 | 50 | 79 | 0 | <0.0001 |
Schauer et al. randomized 150 obese patients with poorly controlled T2DM to receive intensive medical therapy alone, including newer agents such as incretin analogues, versus medical therapy plus RYGB or SG (Table 29.4). More than one-third of patients (36 %) had a BMI less than 35 kg/m2. After 12 months, medical therapy plus metabolic surgery achieved glycemic control in significantly more patients than with medical therapy alone. Homeostasis model assessment of insulin resistance (HOMA-IR) improved significantly after each of the two surgical procedures, as compared with medical therapy alone. The use of drugs to lower glucose, lipid, and blood pressure levels decreased significantly after both surgical procedures, but increased in patients on medical therapy alone [13].
A randomized controlled trial of 60 severely obese diabetic patients by Mingrone et al. reported that RYGB and BPD were associated with an increased rate of remission of T2DM (relative risk, 7.5 and 9.5, respectively) and significant reduction in glycated hemoglobin as compared with medical therapy after 2 years (Table 29.4). The beneficial effects of surgery on the lipid profile were also significant; total cholesterol levels normalized in 100 % and 27 % in the surgical and medical groups, respectively [14].
Dixon et al. compared LAGB with conventional medical therapy in obese patients with newly diagnosed T2DM (<2 years) of mild severity (glycated hemoglobin <7.5 %) (Table 29.4). This randomized controlled trial demonstrated surgical weight loss was more effective than best medical management in terms of weight loss, glycemic control, and diabetes remission rates. Resolution of components of the metabolic syndrome and reduction in antidiabetic, antihypertensive, and cholesterol-lowering medications were also seen in the surgical arm [15].
The Swedish Obese Subjects Study, a large nonrandomized prospective trial with long follow-up time, also clearly showed higher diabetes remission rates after surgery (>68 % VBG) but with gradual recurrence over time in some patients (Table 29.4). The proportion of patients with remission of T2DM at 2 and 10 years following bariatric operations was 72 and 36 %, respectively [16].
High Level of Evidence Studies Comparing Two Metabolic Surgical Procedures
Currently, a relative paucity of high-quality studies comparing surgical procedures head to head is available to clearly define the efficacy of different metabolic operations (Table 29.5) [1, 2, 10]. The operations differ in the degree of benefit they impart on an individual’s state of metabolic derangement, with diversionary procedures demonstrating more profound effects, at least initially, than non-diversionary procedures [1–6].
Table 29.5
High level of evidence studies comparing two metabolic surgical procedures
Author | Year | Study type | BMI (kg/m2) | Follow-up (years) | Procedure 1 (n) | Procedure 2 (n) | Outcome | Outcome with procedure 1 | Outcome with procedure 2 | P value |
|---|---|---|---|---|---|---|---|---|---|---|
Schauer et al. [13] | 2012 | RCT | 27–43 | 1 | RYGB (50) | SG (49) | BMI change (kg/m2) | 10 ± 3 | 9 ± 3 | 0.03a |
Diabetes remissionb | 42 % | 27 % | 0.1 | |||||||
Resolution of MS (%) | 65 % | 59 % | 0.52 | |||||||
GI leak (n) | 0 | 1 | NR | |||||||
Reoperation (n) | 3 | 1 | NR | |||||||
Lee et al. [18] | 2011 | RCT | 25–35 | 1 | MGB (30) | SG (30) | Excess weight loss (%) | 94 ± 33 % | 76 ± 39 % | 0.06 |
Diabetes remissionb | 93 % | 47 % | 0.02a | |||||||
Resolution of MS (%) | 93 % | 40 % | <0.001a | |||||||
GI leak (n) | 0 | 0 | NR | |||||||
Reoperation (n) | 0 | 0 | NR | |||||||
Pournaras et al. [19] | 2010 | NRCT | ≥35 | 3 | RYGB (22) | LAGB (12) | Excess weight loss (%) | 63 % | 62 % | 0.92 |
Diabetes remissionb | 72 % | 17 % | 0.001a
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Related posts: Duodenal Switch: Technique and Outcomes
The Rationale for Metabolic Surgery
Liability Reduction, Patient Safety, and Economic Success in Bariatric Surgery
 Operative Outcomes of Bariatric Surgery in Patients with a Low Body Mass Index (30–35 kg/m2)
 Robotics in Bariatric Surgery
 Body Contouring After Massive Weight Loss
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