Journal of Diabetology

EDITORIAL
Year
: 2021  |  Volume : 12  |  Issue : 2  |  Page : 111--113

Impact of bariatric surgery on body composition and metabolic profile in obese patients with diabetes: A commentary


Rajeev Chawla 
 North Delhi Diabetes Centre, New Delhi, India

Correspondence Address:
Dr. Rajeev Chawla
North Delhi Diabetes Centre, New Delhi.
India




How to cite this article:
Chawla R. Impact of bariatric surgery on body composition and metabolic profile in obese patients with diabetes: A commentary.J Diabetol 2021;12:111-113


How to cite this URL:
Chawla R. Impact of bariatric surgery on body composition and metabolic profile in obese patients with diabetes: A commentary. J Diabetol [serial online] 2021 [cited 2021 Apr 16 ];12:111-113
Available from: https://www.journalofdiabetology.org/text.asp?2021/12/2/111/312656


Full Text



The term “diabesity” coined by Dr. Ethan Sims encompasses the intricate relationship between type 2 diabetes (T2DM) and obesity in a single word. It is a well established fact that most patients with T2DM are overweight or obese, while, on the other hand, the monumental rise in prevalence of obesity globally is the single largest contributor to the rising epidemic of T2DM. Obesity contributes to insulin resistance that eventually predisposes to metabolic disorders, including prediabetes, T2DM, and the metabolic syndrome. Any intervention that targets weight loss thus forms the foundation of halting not only the progression from prediabetes to T2DM in obese individuals but is also an essential feature of any T2DM management plan encom passing lifestyle modifications, medical nutrition therapy, and pharmacotherapy. Therefore, addressing obesity becomes ma ndatory as part of any treatment plan for T2DM as well as chronic diseases. Furthermore, various antihyperglycemic therapies associated with weight gain may pose an additional challenge in attempting or sustaining weight loss especially in obese patients with T2DM.

With advancements in science and technology, bariatric surgery has fast emerged as a powerful tool in our fight against obesity and T2DM. Owing to its proven role in metabolic regulation, the gastrointestinal tract has now become an important target to treat T2DM, especially on a background of mounting evidence demonstrating T2DM remission with different surgical manipulations of the gastrointestinal tract (metabolic surgery). Besides weight loss per se, various other mechanisms are postulated to mediate the beneficial effects of bariatric surgery independent of weight loss. These include effects on tissue-specific insulin sensitivity, improvement in β-cell function, modulation of the incretin responses, and changes in bile acid composition and flow. Furthermore, bariatric surgery results in favorable modifications of the gut microbiome, changes in intestinal glucose metabolism as well as increased brown adipose tissue metabolic activity. Increased rates of T2DM remission and reduced relapse risks are seen in patients with a relatively shorter duration of T2DM, those with a better preoperative glycemic control, and those with a more profound weight loss.

Bariatric surgery results in a significant amount of weight loss, almost complete regression of T2DM, and a dramatic improvement in cardiometabolic risk factors both short term, as well as over an intermediate period of time, post surgery. Furthermore, metabolic surgery may result in durable weight loss, prevent T2DM and some forms of cancer, improve overall glycemia result in significant remission rates of T2DM, and ultimately reduce total and cause-specific mortality over a long term. In terms of weight loss and T2DM remission amongst the four established surgical procedures, the efficacy is highest with biliopancreatic diversion followed by Roux-en-Y gastric bypass, followed by sleeve gastrectomy and the least is seen with laparoscopic adjustable gastric banding.

The current guidelines[1] recommend bariatric surgery in diabetic patients with Class III obesity (BMI ≥40 kg/m2) regardless of their glycemic control, and in patients with class II obesity (BMI between 35 and 39.9 kg/m2), with poorly controlled T2DM despite lifestyle and optimal medical therapy. Surgery should also be considered in patients with Class I obesity (BMI between 30 and 34.9 kg/m2) with poorly controlled T2DM despite optimal medical treatment. IDF 2011[2] has approved bariatric surgery in Asian patients with poorly controlled T2DM with BMI 27.5–32.5 kg/m2 in the presence of any CV risk factor.

There is a direct relationship between body mass index and increasing insulin resistance leading to T2DM. Obese individuals have increased amounts of NEFA, glycerol, proinflammatory cytokines, and other hormones that contribute to insulin resistance which on a background of β-cell dysfunction results in development of T2DM. Hence weight loss is an integral part of any diabetes prevention strategy in overweight/obese individuals with prediabetes.

Various studies have shown a significant improvement in glycemic control, blood pressure, and dyslipidemia with a weight loss of 5–10% from baseline.[3] Bariatric surgery results in a substantive and sustained weight loss for most patients, making it the most effective therapy for obesity management and resolution of T2DM. The Swedish Obesity Subjects (SOS) study was a long-term, prospective, controlled trial that demonstrated a sustained mean reduction in weight to the tune of 18% by 20 years, in contrast to matched controls on usual medical care who failed to show any significant weight change. Additionally, bariatric surgery has shown improvement or remission of diabetes in upto 80%, a reduction in diabetes incidence by 73%, as well as improvements in blood pressure and dyslipidemia. Furthermore, bariatric surgery was associated with decreased incidence of myocardial infarction (29%), stroke (34%), female cancers (42%), and overall mortality (30–40%)[4]

Many studies conducted globally[5],[6],[7] as well as in India[8],[9] have demonstrated benefits of weight loss after bariatric surgery. However, data in South Asians and particularly in Indians with regard to alterations in various parameters of body composition after bariatric surgeryin obese patients with diabetes are still very scant.

The study by Sundaramoorthy Chandru et al.[10] published in this issue of Journal of Diabetology evaluates the changes in body composition, central obesity (visceral and liver fat), and proinflammatory markers, after bariatric surgery in obese Asian Indians with prediabetes and diabetes.This is a 1-year follow-up study of 30 obese patients (BMI of 30–40 kg/m2) with prediabetes and diabetes who underwent bariatric surgery at a renowned tertiary care diabetes center in South India. HbA1c, adiponectin, liver enzymes, ferritin, and high-sensitive C-reactive protein (hs-CRP) were tested before surgery and then 6 and 12 months postoperatively. Body composition analysis and ultrasound hepatic fat grading were done before and at 6 and 12 months’ post surgery.

The baseline HbA1c 8.3 ± 1.8% reduced to a commendable 6.1 ± 0.8% at 12 months after surgery. The percent body fat, visceral fat area, and slim lean mass significantly reduced at 12 months compared to baseline (P < 0.001). Hepatic steatosis and liver enzymes also showed a significant reduction at 12 months compared to baseline. Also hs-CRP and ferritin were significantly reduced (P < 0.05) at 12 months post-op compared to baseline. Serum adiponectin levels significantly increased after the surgery which underscores the fact that Bariatric surgery can be effective in reducing total body fat, visceral fat area, hepatic steatosis as well as an improvement in liver enzyme levels. The improvements in hs-CRP, ferritin, and adiponectin following surgery highlight a favorable change in metabolic milieu in obese T2DM patients which may translate into improved CV outcomes in the long term in these high-risk patients.

The strength of this study is the comprehensive evaluation of subjects at baseline followed up by the stepwise follow-up at 6 and 12 months. However, the major limitations of this study are small sample size and lack of a control group. Another limitation is the evaluation of hepatic steatosis by ultrasound, whereas MRI abdomen or liver biopsy would be gold standard tests for this. But it is quite understandable that liver biopsy and MRI abdomen might not have been feasible as this is essentially a real-world study. The reduction in the central obesity has clinical importance because Indians have the typically unique phenotypic constellation of metabolic dysregulation which is quite comprehensively addressed by bariatric surgery.

This study also sets a base for need for further longer duration follow-up studies to understand the intricate changes in body composition post bariatric surgery, in particular central obesity and muscle mass in Asian Indian patients with prediabetes and diabetes, and whether improved metabolic profile will definitively translate into CV risk or CV death reduction in these high-risk groups.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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