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Page 2 of 7 Veilleux et al. Mini-invasive Surg 2020;4:4 I http://dx.doi.org/10.20517/2574-1225.2020.01

A DECADE OF DISCOVERY
Historically, the primary treatment for diabetes was through behavioral modification and pharmacologic
treatment. Frequently, combination therapy would be necessary, increasing the number of medications
[5]
prescribed to patients . Although glucose control was improved, management often became more
challenging for clinicians, and many patients were burdened with increased costs, intolerable side effects,
and poor compliance. The overall goal was always to improve glycemic control; however, remission or
cure of the disease was often thought to be unattainable. Even with maximal drug therapy, some patients
still struggled with achieving desired HbA1C levels. Given these difficulties in management, the beneficial
effects of surgery on glycemic control garnered immediate attention.

While observational studies were abundant, the emergence of several randomized controlled trials (with
long-term follow up) helped to raise awareness in both the medical and surgical communities regarding the
significant diabetic improvement seen after metabolic and bariatric surgery. Not only was surgery found to
be effective, but it showed superiority to medical therapy in glycemic control, medication reduction, and
[6,7]
weight loss . In 134 patients at five-year follow up, the randomized STAMPEDE trial (Surgical Treatment
and Medications Potentially Eradicate Diabetes Effectively) demonstrated sustained remission of diabetes
(HbA1C < 6.0% without glucose lowering medications) in 22% of the gastric bypass group, 15% of the
sleeve gastrectomy group, and 0% of the medical therapy group. Similarly, comparing medical treatment
to surgery, Mingrone et al. found in 53 patients at five years that 42% of gastric bypass and 68% of
[7]
biliopancreatic diversion patients were able to achieve remission of their diabetes (HbA1C < 6.5% without
glucose lowering medications) while none of those in the medical treatment group had.

The outcomes from these as well as many other studies helped to broaden the awareness of surgery as a
tool for the treatment of diabetes and extend this knowledge outside the surgical community. Given the
overwhelming evidence, at the 2nd Diabetes Surgery Summit, a consensus was reached among international
[8,9]
diabetes organizations to promote the use of bariatric surgery for type 2 diabetes . The endorsement
was approved by many medical and surgical societies including the American Diabetes Association, the
[9]
International Diabetes Federation, ASMBS, Diabetes UK, and The American College of Surgeons . The
consensus stated that “metabolic surgery should be recommended to treat T2DM in patients with class III
2
2
obesity [body mass index (BMI) ≥ 40 kg/m ] and in those with class II obesity (BMI 35.0-39.9 kg/m ) when
hyperglycemia is inadequately controlled by lifestyle and optimal medical therapy. Surgery should also be
2
considered for patients with T2DM and BMI 30.0-34.9 kg/m if hyperglycemia is inadequately controlled
despite optimal treatment with either oral or injectable medications” . Despite many publications, it is a
[8,9]
continued effort for surgeons to spread this knowledge to other physicians (primary care, endocrinology)
as well as to insurance companies. The goal is to reach and obtain coverage for a greater number of patients
who would benefit from bariatric and metabolic surgery.

RISK FACTORS FOR REMISSION
As we discovered the potential for the surgical improvement of diabetes, risk factors for failure of remission
(or likelihood of relapse) also became evident. Increased age, longer duration of diabetes (> 8 years),
preoperative insulin usage, number of oral antidiabetic medications at time of surgery, and poor preop
glycemic control were found to adversely affect outcomes [6,10-12] . It is theorized that these risk factors
represent the pathologic concept of diminished β-cell reserve in the pancreas, and its ability to improve
in response to metabolic surgery. These observations underscore the importance of intervening early with
surgery in the progressive course of diabetes [6,10] .

Initial investigation into remission rates after sleeve gastrectomy by Schauer et al. found 14.9% of patients
[6]
remained in remission at 5 years. However, much of the cohort in the Cleveland study was known to