Bariatric and metabolic surgery to treat type 2 diabetes

Once considered exclusively as a weight loss procedure in patients with severe obesity, there is evidence with more than more than 20 years supporting that metabolic surgery is an effective treatment for type 2 diabetes and that it results in the improvement or the remission in most cases.
Obesity is medically defined as a body mass index ^(BMI) 30 kg / m² or more. It is an important independent risk factor for the development of the disease. About 90% of people with type 2 diabetes are obese or overweight (BMI of at least 25)⁽²¹⁾.

Randomized clinical trials show that metabolic surgery, especially gastric bypass, achieves results of complete remission or improvement of diabetes within two years of more than 90% of patients, in some cases at the time of hospital discharge and even earlier significant weight loss occurs ⁽²²⁾.

Studies show that metabolic surgery is superior to non-surgical treatment that includes drugs. Intensive therapy and intervention in the style of producing long-term diabetes remission with a 25-50% plus surgery patients maintain glycemic control without medication ^{(23) (24)}.

Global clinical guidelines approved by 45 medical professional societies include metabolic surgery as a treatment option for type 2 diabetes in patients with a BMI of 30 or more. ⁽²⁵⁾.

Main Guidelines and Recommendations

2018: The American Society for Metabolic and Bariatric Surgery ^(ASMBS) Position statement on the role of bariatric surgery in class I obesity ^{(BMI 30.0 to 34.9 kg / m2)} states "Particularly given the presence of high quality data in patients with type 2 diabetes, bariatric and metabolic surgery should be strongly considered for patients with a BMI of 30 to 35 kg / m2 and type 2 diabetes." The statement is supported by the American Diabetes Association ^(ADA) and has been endorsed by the American Society of Gastrointestinal and Endoscopic Surgeons (SAGES). ⁽²⁶⁾

2018: ADA's annually updated guidelines “Standards of Medical Care in Diabetes-2018” maintain an emphasis on metabolic surgery for the treatment of type 2 diabetes, which includes 2017- expansion of the indication for metabolic surgery in patients with diabetes inadequately controlled who have mild obesity, with a body mass index as low as 30.

Surgical Treatment of Type 2 Diabetes

Impact of Metabolic Surgery on Diabetes
Meta-analysis of more than 135,000 metabolic surgery patients ^{(mean BMI 47.9)} in 621 studies (1990-2006) found 86.6% of people with type 2 diabetes experienced improvement or remission, and overall excess weight loss (PEP) was 59.9% (American Journal of Medicine, 2009) ⁽²⁷⁾

Metabolic surgery versus medical therapy

Randomized clinical trials have shown that metabolic surgery is more effective than medical treatment and / or lifestyle interventions, including drug therapy in producing remission of diabetes, glycemic control, and weight loss. end of five years of surgical treatment and study drugs show Efficiency (STAMPEDE) in patients with uncontrolled type 2 diabetes (mean BMI 37), Metabolic surgery plus intensive medical therapy treatments is more effective than intensive medicine alone to achieve and maintain glycemic control, weight reduction, reduction, medication and improvements in lipid levels ^{(NEJM, 2017) (28) (29) (30)}

Remission rates for diabetes at one, three, and five years with metabolic surgery were about 40% (42% for gastric bypass; 37% sleeve gastrectomy, 31% (38% gastric bypass; 24% for sleeve gastrectomy), and 26% (sleeve gastric bypass) 29%; 23% sleeve gastrectomy), respectively compared to 12%, 5%, and 5% for medical treatment.

Long-term results with Metabolic Surgery

• Among patients with type 2 diabetes who underwent metabolic surgery, 24% experienced complete, long-term remission - five years or more - of their diabetes; 26% experienced partial remission and 34% improved from baseline; mean excess weight loss was 55% (Annals of Surgery, 2013) ⁽³¹⁾
• Fifteen years after metabolic surgery, 30.4% of patients maintained remission of diabetes, compared with 6.5% of control patients (JAMA, 2014) ⁽³²⁾

Reduction in diabetes-related mortality and health complications

• Metabolic surgery significantly decreases the likelihood of death, leads to lasting improvements in important cardiovascular risk factors, and reduces the risk of developing microvascular complications.
• Severely obese patients who had gastric bypass reduced the risk of mortality from Type II Diabetes by 92% for up to seven years (NEJM, 2007) ⁽³³⁾
• Gastric bypass in patients with type 2 diabetes was associated with a 58% reduction in the relative risk of death from any cause five years after surgery (The Lancet, 2015) ⁽³⁴⁾
• Risk of death from myocardial infarction (heart attack) decreased by nearly 60%
• Risk of non-fatal myocardial infarction suffering or fatal reduced 49%
• At 12 years, patients with type 2 diabetes who had gastric bypass saw lower rates of hypertension (16% vs. 47%) and dyslipidemia compared to those who did not undergo surgery (NEJM, 2017) ⁽³⁵⁾
• Meta-analysis of 17,532 patients in 1,559 studies demonstrate metabolic surgery was superior to medical treatment alone in obese patients for the prevention of microvascular complications of diabetes (OR: 0.16 vs. 0.42), including nephropathy, neuropathy and retinopathy (British Journal of Surgery, 2018) ⁽³⁶⁾
• For patients with diabetes and severe obesity who had metabolic surgery, the risk of microvascular complications at five years was less than half of the patients receiving medical treatment 16.9% vs. 34.7%, respectively (Annals of Internal Medicine, 2018) ⁽³⁷⁾

The safety of metabolic surgery has improved significantly in the last two decades, with continued refinement of minimally invasive approaches (laparoscopic surgery), better training and accreditation, and participation of multidisciplinary teams. The experience and aptitude of the surgeon are essential factors that determine the result of the surgery.

Metabolic surgery in patients with low BMI (Body Mass Index)

• Systematic review of more than 50 studies shows that metabolic surgery in patients with mild to moderately obese renal insufficiency (BMI 30 to 35) produced better glycemic control (range, 0.9 to 1.43 points improvement in levels blood sugar) and weight loss (range, 14.4 to 24 kg) after 12 months to two years compared with nonsurgical treatments (JAMA, 2013) ⁽³⁸⁾
• Diabetes remission was achieved in one gastric bypass 93% and 47% of sleeve gastrectomy patients with a BMI of 24 to 30 one year after surgery (Archives of Surgery, 2011) ⁽³⁹⁾
• Five years data in patients with a BMI less than 35 is shown after metabolic surgery, 36% maintained complete remission of diabetes and 28% maintained partial remission compared to 1.2% and 1.6% in patient treated with medical treatment alone (Archives of Surgery, 2015) ⁽⁴⁰⁾