REVIEW ARTICLE TYPE 2 DIABETES MELLITUS ... - MedIND

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REVIEW ARTICLE. TYPE 2 DIABETES MELLITUS - EXPLORING. THE AVENUE OF BARIATRIC SURGERY. S RAO*, JAIN VV** , GUPTA DO*** . Diabetes is a ...
REVIEW ARTICLE TYPE 2 DIABETES MELLITUS - EXPLORING THE AVENUE OF BARIATRIC SURGERY. S RAO*, JAIN VV** , GUPTA DO*** .

Diabetes is a growing public health problem world-wide and especially in India which pronounced as the capital of diabetes by WHO. Rapid urbanization is giving rise to a multitude of life style changes which adversely affect the metabolic processes, leading to an epidemic of diseases associated with such life style changes. It is predicted that by the year 2025, the maximum prevalence of diabetes would be in India and every 4th diabetic in the world would be an Indian.1,2,3. The socioeconomic burden posed by this disease is enormous due its spectrum of complications ranging from peripheral vascular disease (PVD) to coronary artery disease (CAD), chronic kidney disease (CKD), blindness etc. Obesity is an independent risk factor for development of diabetes. In United sates more than 50% patients diagnosed with type 2 DM are obese with a BMI > 30kg/m2 and about 9% are morbidly obese with a BMI > 40kg/m25. this epidemic of obesity has become widespread in the developed world and is spreading rapidly in the developing world4. Obesity predisposes to type 2 diabetes mellitus (T2DM) through various mechanisms like insulin resistance, impaired glucose tolerance and pancreatic beta cell failure. The adipocyte which is also an endocrine organ releases an array of humoral factors which are responsible for insulin resistance as well as a chronic proinflammatory state. Even a moderate weight loss of 10kgs can cause 30-50% fall in fasting blood glucose (FBG) and 15% fall in glycated hemoglobin (HbA1c) in diabetic patients5.

* Assit. prof., *** Prof. & Head of deptt., Deptt. of Surgery, MGIMS ** Asstt prof Deptt. of Medicine.

It is thus not entirely hypothetical to think that weight reduction may offer mortality benefits in association with other factors to maintain euglycemia. Modern medicine offers a concoction of various Insulins and oral hypoglycemic agents targeted to obtain euglycemia. Some of them help in weight reduction but many cause weight gain which further compounds the situation. Lifestyle intervention programs with diet therapy, behavior modification, exercise programs, and pharmacotherapy are widely used in various combinations for obese T2DM patients. Unfortunately with extremely rare exceptions, clinically significant weight loss is generally very modest and transient, particularly in patients with severe obesity6. Naturally with the commonest options for weight loss like diet and exercise taking a toss, the more lucrative option is Bariatric surgery. Obese diabetes undergoing bariatric surgery show a phenomenal improvement in their glycemic control within days of bariatric surgery and has also been mentioned as "cure for diabetes". It is prudent to say that Bariatric surgery is that ray of hope for those obese and morbidly obese individuals in whom life style interventions are not showing appropriate results. Bariatric surgery includes a spectrum of surgical procedures which can be performed in obese individuals depending upon their varied indications. As per the latest guidelines indications for bariatric surgery include either a BMI >= 40kg/m2 or a BMI of >= 35 kg/m2 with other co morbidities like diabetes mellitus, hypertension or cardiovascular disease7. In a recently published study, 80 adults with mild to moderate obesity (BMI 30-35 kg/m2) were randomized to nonsurgical intervention (very-low calorie diet, Orlistat, and lifestyle change) or to surgical intervention (Gastric banding). Surgical treatment was significantly more effective than nonsurgical therapy in reducing weight, resolving the metabolic syndrome, and improving quality of life during a 24-month treatment program. At 2 years, the surgical group had greater weight loss, with a mean of 21.6% of initial weight loss and 87.2% of excess weight loss, whereas the nonsurgical group had a loss of 5.5% of initial weight and 21.8% of excess weight (P _0.001)8. In a series of 165 patients of diabetes and impaired glucose tolerance Pories et al found a long lasting resolution of diabetes, normalization of HbA1c in 83% of diabetics and 99% of patients with IGT at year following GPB surgery9.

There are various types of procedure in bariatric surgery and are classified as Restrictive, Malabsorptive or Combined. Restrictive procedures include laparoscopic adjustable gastric banding (LABG) and vertical banded gastroplasty (VBG) which primarily reduce the volume of the stomach which decrease the food intake and give early satiety. Malabsorptive procedures like biliopancreatic diversion (BPD) decrease the length of the small intestine and decrease the absorption of nutrients from small gut. Combined procedures include the Roux-en-Y gastric bypass (RYGB) which is the gold standard of treatment for obesity7. Both the Malabsorptive and combined procedures alter the secretion of orexigenic and anorexigenic gut peptides which interact with the appetite centres in the arcuate nucleus of the hypothalamus and cause decrease in the appetite. It is postulated that the sudden glycemic control within days of surgery in diabetic obese individuals is probably due to caloric restriction and alteration in hormonal levels controlling insulin secretion. These bariatric procedures affect the enteroinsular axis and alter the levels of Incretins (increase in GLP- 1, glucagon like pepetide-1 and reduction in GIP, glucose dependent insulinotropic peptide) as well as cause decreased secretion of ghrelins. The bariatric literature has consistently demonstrated a significant effect of bariatric surgery in T2DM remission in patients with BMI 35kg/m2. T2DM resolution or remission has usually been defined as HbA1C values ranging from