Beta-cell function improvement after biliopancreatic diversion in subjects with type 2 diabetes and morbid obesity

Ten-year remission rates in insulin-treated type 2 diabetes after biliopancreatic diversion with duodenal switch

BACKGROUND

Biliopancreatic diversion with duodenal switch (BPD-DS) confers the highest rate of type 2 diabetes (T2D) remission compared with other bariatric procedures. Previous studies suggest that type of antidiabetic therapy used before surgery and duration of disease influence postsurgical glycemic outcomes. Short-term, progressive improvement in insulin sensitivity and beta-cell function after metabolic surgery in patients with noninsulin-treated T2D has been demonstrated. Whether patients with more advanced disease can achieve sustained remission remains unclear.

OBJECTIVE

The aim of this study was to assess long-term glycemic outcomes in insulin-treated patients with T2D after BPD-DS and identify predictors of sustained diabetes remission or relapse.

SETTING

University-affiliated tertiary care center.

METHODS

Data from 141 patients with insulin-treated T2D who underwent BPD-DS between 1994 and 2006 with 10 years of follow-up data were collected from a prospective electronic database.

RESULTS

Follow-up was available in 132 patients (91%). At 10 years after metabolic surgery, 90 patients (68.1%) had a complete remission of diabetes, 3 (2.3%) had a partial remission, 21 (15.9%) had an improvement, and 3 (2.3%) were unchanged in their diabetes status. Fourteen patients died during the 10-year follow-up period. Relapse after an initial period of remission occurred in 15 (11.4%) patients. Insulin discontinuation was achieved in 97%. Duration of diabetes was an independent predictor of nonremission at 10 years.

CONCLUSIONS

The BPD-DS maintains remission at 10 years postoperatively in patients with more advanced diabetes. Long-term benefits of the BPD-DS on weight loss and glycemic control should be considered when offering metabolic surgery to patients with insulin-treated T2D.

Laparoscopic Ileal Interposition with Diverted Sleeve Gastrectomy Versus Laparoscopic Transit Bipartition with Sleeve Gastrectomy for Better Glycemic Outcomes in T2DM Patients

BACKGROUND

Metabolic procedures provide better outcomes for obese patients with type 2 diabetes mellitus. Our aim was to compare the glycemic regulation in patients that have undergone the laparoscopic ileal interposition with diverted sleeve gastrectomy (II-DSG), laparoscopic transit bipartition with sleeve gastrectomy (TB-SG), and laparoscopic sleeve gastrectomy (LSG) throughout a 12-month follow-up period retrospectively.

METHODS

This study considered patients with T2DM who underwent metabolic procedures. The postoperative changes in the glucose, C-peptide, HbA1c, HOMA-IR, insulin, cholesterol, body mass index, and total weight loss (TWL) were compared retrospectively. The intended outcome was to reach a long lasting fasting blood glucose (FBG) <126 mg/dl. A multivariate regression analysis was applied to define the predictive markers in glucose regulation.

RESULTS

Present study consisted of 83 patients with a mean age of 47.25 ± 6.58 years, mean preoperative BMI of 37.36 ± 2.71 kg/m², and mean outcomes in the HbA1C and FBG of 9.05 ± 1.33% and 237 ± 15 mg/dl, respectively. There were similar correlations in BMI and total weight loss (TWL). At 12-month follow up period, compared to LSG group, TB-SG and II-DSG groups have higher remission proportions (35.3, 67.9, 54.7, respectively, p < 0.05) with similar TWL% (22.35, 27.14, 23.16%) outcomes. The II-DSG and TB-SG results drew closer together toward the end of this study interval unlike the LSG group.

CONCLUSION

Our results showed that II-DSG and TB-SG ensured significant regression rates during the follow-up period. Since the TB-SG achieved these outcomes by finite anastomoses and intervening segments, it was considered to be a superior procedure compared to II-DSG and LSG procedures.

Time to Glycemic Control - an Observational Study of 3 Different Operations

BACKGROUND

Medical treatment fails to provide adequate control for many obese patients with type 2 diabetes mellitus (T2DM). A comparative observational study of bariatric procedures was performed to investigate the time at which patients achieve glycemic control within the first 30 postoperative days following sleeve gastrectomy (SG), mini-gastric bypass (MGB), and diverted sleeve gastrectomy with ileal transposition (DSIT).

METHODS

Included patients had a body mass index (BMI) ≥30 kg/m²; T2DM for ≥3 years, HbA_1C > 7 % for ≥3 months, and no significant weight change (>3 %) within the prior 3 months. Surgical procedures performed were SG (n = 49), MGB (n = 93), and DSIT (n = 109). The primary endpoint was the day within the first postoperative month on which mean fasting capillary glucose levels reached <126 mg/dL. Multivariate logistic regression analysis was used to identify predictors of glycemic control.

RESULTS

The cohort included 251 patients with a mean BMI of 36.04 ± 5.76 kg/m²; age, 52.84 ± 8.52 years; T2DM duration, 13.09 ± 7.54 years; HbA_1C, 8.82 ± 1.58 %. On the morning of surgery, mean fasting plasma glucose was 177.63 ± 51.3 mg/dL; on day 30, 131.35 ± 28.7 mg/dL (p < 0.05). Mean fasting plasma glucose of <126 mg/dL was reached in the DSIT group (124.36 ± 20.21 mg/dL) on day 29, and in the MGB group (123.61 ± 22.51 mg/dL), on day 30. The SG group did not achieve target mean capillary glucose level within postoperative 30 days.

CONCLUSION

During the first postoperative month, glycemic control (<126 mg/dL) was achieved following DSIT and MGB, but not SG. Preoperative BMI and postprandial C-peptide levels were independent predictors of early glycemic control following DSIT.

High baseline C-reactive protein levels predict partial type 2 diabetes mellitus remission after biliopancreatic diversion

BACKGROUND AND AIMS

Several studies demonstrated that surgery can improve inflammation parameters, such as C-reactive protein (CRP). Few biomarkers have been investigated to potentially predict type 2 diabetes mellitus (T2DM) remission. We aimed at determining whether pre-surgery serum CRP levels could predict T2DM remission after 3 years in patients undergoing bariatric surgery, especially biliopancreatic diversion (BPD).

METHODS AND RESULTS

This study was conducted from 2007 to 2009 at the Surgical Department of the University of Genoa, Italy. Forty-four patients with T2DM undergoing BPD (n = 38) or Roux-en-Y gastric bypass (n = 6) were enrolled. The primary endpoint was to evaluate whether pre-surgery CRP levels could predict T2DM partial remission at 3-year follow-up. Secondary endpoints were to assess whether glycaemic, lipid, and inflammatory parameters modified during the follow-up. At baseline, patients with T2DM ranged from overweight to morbid obesity, had mild dyslipidaemia, and a low-grade inflammation. Bariatric surgery improved body weight, lipid and glycaemic profile both at 1- and 3-year follow-up. Pre-surgery CRP levels progressively decreased at 1- and 3-year follow-up. Among inflammatory pre-surgery parameters, only high CRP levels were shown to predict T2DM partial remission after 3 years. Multivariate analysis confirmed the predictive value of pre-surgery CRP levels independently of age, gender, type of surgery, and body mass index.

CONCLUSION

Bariatric surgery, in particular BPD, improved both metabolic and inflammatory biomarkers at 1- and 3-year follow-up. Pre-surgery high CRP levels predicted 3-year T2DM partial remission, indicating a promising target population to be especially treated with BPD.

What is the role of bariatric surgery in the management of obesity?

Diet, exercise, cognitive behavioral therapy and pharmacotherapy are some of the means of assisting patients to lose weight, with bariatric surgery being the most effective. Over the last two decades, the increased awareness of the systemic benefits of bariatric surgery, as well as the improved safety and the wider use of the laparoscopic approach, has made bariatric surgery flourish. In the United Kingdom, the adjustable gastric band (10%), vertical sleeve gastrectomy (37%) and Roux-en-Y gastric bypass (45%) are the three most common procedures. Obesity-associated mortality and co-morbidities such as type 2 diabetes, hypertension, dyslipidemia, obstructive sleep apnea, renal dysfunction and depression improve significantly with bariatric surgery. The mechanisms of weight loss extend beyond restriction and malabsorption and include changes in hunger and satiety, food preferences, and possibly energy expenditure. Despite its safety and efficacy, bariatric surgery is underutilized as less than 1% of adults with obesity receive it. In view of the evolution of obesity into a global threat, access to bariatric surgery should be increased, whilst developing safer and less invasive weight loss treatments.

From bariatric to metabolic surgery: Looking for a “disease modifier” surgery for type 2 diabetes

In this review the recent evolution of the comprehension of clinical and metabolic consequences of bariatric surgery is depicted. At the beginning bariatric surgery aim was a significant and durable weight loss. Later on, it became evident that bariatric surgery was associated with metabolic changes, activated by unknown pathways, partially or totally independent of weight loss. Paradigm of this “metabolic” surgery is its effects on type 2 diabetes mellitus (T2DM). In morbid obese subjects it was observed a dramatic metabolic response leading to decrease blood glucose, till diabetes remission, before the achievement of clinically significant weight loss, opening the avenue to search for putative anti-diabetic “intestinal” factors. Both proximal duodenal (still unknown) and distal (GLP1) signals have been suggested as hormonal effectors of surgery on blood glucose decrease. Despite these findings T2DM remission was never considered a primary indication for bariatric surgery but only a secondary one. Recently T2DM remission in obese subjects with body mass index (BMI) greater than 35 has become a primary aim for surgery. This change supports the idea that “metabolic surgery” definition could more appropriate than bariatric, allowing to explore the possibility that metabolic surgery could represent a “disease modifier” for T2DM. Therefore, several patients have undergone surgery with a primary aim of a definitive cure of T2DM and today this surgery can be proposed as an alternative therapy. How much surgery can be considered truly metabolic is still unknown. To be truly “metabolic” it should be demonstrated that surgery could cause T2DM remission not only in subjects with BMI > 35 but also with BMI < 35 or even < 30. Available evidence on this topic is discussed in this mini-review.

European Guidelines for Obesity Management in Adults

Obesity is a chronic metabolic disease characterised by an increase of body fat stores. It is a gateway to ill health, and it has become one of the leading causes of disability and death, affecting not only adults but also children and adolescents worldwide. In clinical practice, the body fatness is estimated by BMI, and the accumulation of intra-abdominal fat (marker for higher metabolic and cardiovascular disease risk) can be assessed by waist circumference. Complex interactions between biological, behavioural, social and environmental factors are involved in regulation of energy balance and fat stores. A comprehensive history, physical examination and laboratory assessment relevant to the patient's obesity should be obtained. Appropriate goals of weight management emphasise realistic weight loss to achieve a reduction in health risks and should include promotion of weight loss, maintenance and prevention of weight regain. Management of co-morbidities and improving quality of life of obese patients are also included in treatment aims. Balanced hypocaloric diets result in clinically meaningful weight loss regardless of which macronutrients they emphasise. Aerobic training is the optimal mode of exercise for reducing fat mass while a programme including resistance training is needed for increasing lean mass in middle-aged and overweight/obese individuals. Cognitive behavioural therapy directly addresses behaviours that require change for successful weight loss and weight loss maintenance. Pharmacotherapy can help patients to maintain compliance and ameliorate obesity-related health risks. Surgery is the most effective treatment for morbid obesity in terms of long-term weight loss. A comprehensive obesity management can only be accomplished by a multidisciplinary obesity management team. We conclude that physicians have a responsibility to recognise obesity as a disease and help obese patients with appropriate prevention and treatment. Treatment should be based on good clinical care, and evidence-based interventions; should focus on realistic goals and lifelong multidisciplinary management.

Effects of gastric bypass on type 2 diabetes in patients with BMI 30 to 35

BACKGROUND

This study aims to investigate if the benefits on glycemic control following Roux-en-Y gastric bypass (RYGB) in morbidly obese type 2 diabetes (T2DM) patients are maintained in the 30-35 kg/m(2) BMI (body mass index) range, comparing results with those in literature.

METHODS

The study participants were twenty T2DM patients aging 35-70 years, BMI 30.0-34.9 kg/m(2), minimum diabetes duration 3 years, glycosylated haemoglobin (HbA1c) ≥7.5% despite good clinical practice medical therapy, submitted to laparoscopic RYGB, and monitored during 36 months. Twenty-seven matched diabetic patients as controls.

RESULTS

Five females, mean age 57 (42-69) years, weight 96.0 (70-111) kg, BMI 32.9 (30.3-34.9) kg/m(2), waist circumference 112 (100-128) cm, diabetes duration 14 (3-28) years, HbA1c 9.5 (7.5-14.2) %, and C-peptide 3.2 (1,6-9.1) mcg/l. Ten patients were on insulin. There was no mortality, and there were two major late complications. BMI and waist decreased stabilizing around 25 kg/m(2) and 92 cm. Fasting serum glucose and HbA1c reached values around 150 mg/dl and 7%, which subsequently maintained. There was remission in 25% of cases, control 45%, and all the others improved. HOMA-IR and insulin sensitivity index normalized at 1 month, then maintained. AIR and insulinogenic index showed no postoperative changes. Diabetes remission correlated negatively with duration (p < 0.05; r (2) = 0.61), while control positively with C-peptide (p < 0.05; r (2) = 0.19). In the control group, FSG, HbA1c, serum triglyceride, and cholesterol significantly decreased with considerable progressive increase of antidiabetic/antihyperlipemic therapy. All patients had HbA1c >7% at 2-3 years.

CONCLUSIONS

Glycemic control obtained by RYGB in this study was less good than that reported by others, apparently due to different patient selection criteria. Our results do not support RYGB weight loss-independent effect on beta-cell function in the T2DM patients with BMI 30-35 kg/m(2).

Impaired increase of plasma abscisic Acid in response to oral glucose load in type 2 diabetes and in gestational diabetes

The plant hormone abscisic acid (ABA) is present and active in humans, regulating glucose homeostasis. In normal glucose tolerant (NGT) human subjects, plasma ABA (ABAp) increases 5-fold after an oral glucose load. The aim of this study was to assess the effect of an oral glucose load on ABAp in type 2 diabetes (T2D) subjects. We chose two sub-groups of patients who underwent an oral glucose load for diagnostic purposes: i) 9 treatment-naive T2D subjects, and ii) 9 pregnant women with gestational diabetes (GDM), who underwent the glucose load before and 8–12 weeks after childbirth. Each group was compared with matched NGT controls. The increase of ABAp in response to glucose was found to be abrogated in T2D patients compared to NGT controls. A similar result was observed in the women with GDM compared to pregnant NGT controls; 8–12 weeks after childbirth, however, fasting ABAp and ABAp response to glucose were restored to normal in the GDM subjects, along with glucose tolerance. We also retrospectively compared fasting ABAp before and after bilio-pancreatic diversion (BPD) in obese, but not diabetic subjects, and in obese T2D patients, in which BPD resulted in the resolution of diabetes. Compared to pre-BPD values, basal ABAp significantly increased 1 month after BPD in T2D as well as in NGT subjects, in parallel with a reduction of fasting plasma glucose. These results indicate an impaired hyperglycemia-induced ABAp increase in T2D and in GDM and suggest a beneficial effect of elevated ABAp on glycemic control.

Nutrition and metabolic support recommendations for the bariatric patient

Managing the metabolic needs of the patient with obesity is a challenge unto itself without the added demands of accounting for an altered gastrointestinal tract. Nevertheless, with about 200,000 bariatric procedures being performed annually in the United States, clinicians must be prepared to manage the critically ill bariatric surgery patient. This article reviews the recent literature relating to nutrient needs and metabolic support for the bariatric patient. Bariatric patients are at risk for several micronutrient deficiencies, including vitamins D and B₁₂, calcium, and iron; some bariatric procedures affect macronutrient needs as well. Literature on nutrition support guidelines for the bariatric population is limited. However, with an understanding of the anatomical and physiological effects of bariatric surgery, recent guidelines for critically ill patients with obesity can be applied to the bariatric surgery population. The unique needs of the bariatric population, such as susceptibility to micronutrient deficiencies and specialized access routes, must be considered to provide safe and efficacious nutrition support. Further research is necessary to develop specific nutrition support recommendations for the bariatric population.

Interdisciplinary European guidelines on metabolic and bariatric surgery

In 2012, an expert panel composed of presidents of each of the societies, the European Chapter of the International Federation for the Surgery of Obesity (IFSO-EC), and of the European Association for the Study of Obesity (EASO), as well as of the chair of EASO Obesity Management Task Force (EASO OMTF) and other key representatives from IFSO-EC and EASO, devoted the joint Medico-Surgical Workshop of both institutions to the topic of metabolic surgery in advance of the 2013 European Congress on Obesity held in Liverpool. This meeting was prompted by the extraordinary advancement made in the field of metabolic and bariatric surgery during the past decade. It was agreed to revise and update the 2008 Interdisciplinary European Guidelines on Surgery of Severe Obesity produced by focusing in particular on the evidence gathered in relation to the effects on diabetes and the changes in the recommendations of patient eligibility criteria. The expert panel allowed the coverage of key disciplines in the comprehensive management of obesity and obesity-associated diseases, aimed specifically at updating the clinical guidelines to reflect current knowledge, expertise and evidence-based data on metabolic and bariatric surgery.

β-Cell function improvements in grade I/II obese subjects with type 2 diabetes 1 month after biliopancreatic diversion: results from modeling analyses of oral glucose tolerance tests and hyperglycemic clamp studies

OBJECTIVE

To investigate the effect of biliopancreatic diversion (BPD) surgery on β-cell function in grade I and II obese patients with type 2 diabetes using oral and intravenous glucose loads.

RESEARCH DESIGN AND METHODS

Sixty-eight women were divided into the following three groups: 19 lean-control (23.0 ± 2.2 kg/m(2)) and 18 obese-control (35.0 ± 4.8 kg/m(2)) subjects with normal glucose tolerance, and 31 obese patients with type 2 diabetes (36.3 ± 3.7 kg/m(2)). Of the 31 diabetic women, 64% underwent BPD (n = 20, BMI: 36.5 ± 3.7 kg/m(2)) and were reassessed 1 month after surgery. Oral glucose tolerance tests and hyperglycemic clamps were performed. Mathematical modeling was used to analyze basal and stimulated β-cell function, insulin sensitivity (IS), hepatic extraction (HE) of insulin, and delay time of β-cell response to a specific plasma glucose concentration.

RESULTS

After BPD, restoration of the basal disposition index (P < 0.001) and improvement of the stimulated disposition indices in oral and intravenous glucose stimulation of the β-cell were observed (P < 0.05). In both dynamic tests, there were no changes in the delay time of β-cell response. IS for oral glucose stimulation (IS(oral)) and intravenous clamp glucose stimulation (IS(clamp)) was completely normalized (P < 0.001). IS(oral) and IS(clamp) increased approximately 5.0-fold and 3.5-fold, respectively (P < 0.01). The HE of insulin increased in the basal (P < 0.05) and stimulated states (P < 0.01).

CONCLUSIONS

β-Cell function, IS, and HE of insulin improved after BPD, which improved glycemic control.

Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient--2013 update: cosponsored by American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery

The development of these updated guidelines was commissioned by the AACE, TOS, and ASMBS Board of Directors and adheres to the AACE 2010 protocol for standardized production of clinical practice guidelines (CPG). Each recommendation was re-evaluated and updated based on the evidence and subjective factors per protocol. Examples of expanded topics in this update include: the roles of sleeve gastrectomy, bariatric surgery in patients with type-2 diabetes, bariatric surgery for patients with mild obesity, copper deficiency, informed consent, and behavioral issues. There are 74 recommendations (of which 56 are revised and 2 are new) in this 2013 update, compared with 164 original recommendations in 2008. There are 403 citations, of which 33 (8.2%) are EL 1, 131 (32.5%) are EL 2, 170 (42.2%) are EL 3, and 69 (17.1%) are EL 4. There is a relatively high proportion (40.4%) of strong (EL 1 and 2) studies, compared with only 16.5% in the 2008 AACE-TOS-ASMBS CPG. These updated guidelines reflect recent additions to the evidence base. Bariatric surgery remains a safe and effective intervention for select patients with obesity. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient--2013 update: cosponsored by American Association of Clinical Endocrinologists, the Obesity Society, and American Society for Metabolic & Bariatric Surgery

The development of these updated guidelines was commissioned by the AACE, TOS, and ASMBS Board of Directors and adheres to the AACE 2010 protocol for standardized production of clinical practice guidelines (CPG). Each recommendation was re-evaluated and updated based on the evidence and subjective factors per protocol. Examples of expanded topics in this update include: the roles of sleeve gastrectomy, bariatric surgery in patients with type-2 diabetes, bariatric surgery for patients with mild obesity, copper deficiency, informed consent, and behavioral issues. There are 74 recommendations (of which 56 are revised and 2 are new) in this 2013 update, compared with 164 original recommendations in 2008. There are 403 citations, of which 33 (8.2%) are EL 1, 131 (32.5%) are EL 2, 170 (42.2%) are EL 3, and 69 (17.1%) are EL 4. There is a relatively high proportion (40.4%) of strong (EL 1 and 2) studies, compared with only 16.5% in the 2008 AACE-TOS-ASMBS CPG. These updated guidelines reflect recent additions to the evidence base. Bariatric surgery remains a safe and effective intervention for select patients with obesity. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient--2013 update: cosponsored by American Association of Clinical Endocrinologists, the Obesity Society, and American Society for Metabolic & Bariatric Surgery

The development of these updated guidelines was commissioned by the AACE, TOS, and ASMBS Board of Directors and adheres to the AACE 2010 protocol for standardized production of clinical practice guidelines (CPG). Each recommendation was re-evaluated and updated based on the evidence and subjective factors per protocol. Examples of expanded topics in this update include: the roles of sleeve gastrectomy, bariatric surgery in patients with type-2 diabetes, bariatric surgery for patients with mild obesity, copper deficiency, informed consent, and behavioral issues. There are 74 recommendations (of which 56 are revised and 2 are new) in this 2013 update, compared with 164 original recommendations in 2008. There are 403 citations, of which 33 (8.2%) are EL 1, 131 (32.5%) are EL 2, 170 (42.2%) are EL 3, and 69 (17.1%) are EL 4. There is a relatively high proportion (40.4%) of strong (EL 1 and 2) studies, compared with only 16.5% in the 2008 AACE-TOS-ASMBS CPG. These updated guidelines reflect recent additions to the evidence base. Bariatric surgery remains a safe and effective intervention for select patients with obesity. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Interdisciplinary European Guidelines on metabolic and bariatric surgery

In 2012, an outstanding expert panel derived from IFSO-EC (International Federation for the Surgery of Obesity-European Chapter) and EASO (European Association for the Study of Obesity), composed by key representatives of both Societies including past and present presidents together with EASO's OMTF (Obesity Management Task Force) chair, agreed to devote the joint Medico-Surgical Workshop of both institutions to the topic of metabolic surgery as a pre-satellite of the 2013 European Congress on Obesity (ECO) to be held in Liverpool given the extraordinarily advancement made specifically in this field during the past years. It was further agreed to revise and update the 2008 Interdisciplinary European Guidelines on Surgery of Severe Obesity produced in cooperation of both Societies by focusing in particular on the evidence gathered in relation to the effects on diabetes during this lustrum and the subsequent changes that have taken place in patient eligibility criteria. The expert panel composition allowed the coverage of key disciplines in the comprehensive management of obesity and obesity-associated diseases, aimed specifically at updating the clinical guidelines to reflect current knowledge, expertise and evidence-based data on metabolic and bariatric surgery.

Effects of bariatric surgery on glucose homeostasis and type 2 diabetes

Obesity is an important risk factor for type 2 diabetes mellitus (T2DM). Weight loss improves the major factors involved in the pathogenesis of T2DM, namely insulin action and beta cell function, and is considered a primary therapy for obese patients who have T2DM. Unfortunately, most patients with T2DM fail to achieve successful weight loss and adequate glycemic control from medical therapy. In contrast, bariatric surgery causes marked weight loss and complete remission of T2DM in most patients. Moreover, bariatric surgical procedures that divert nutrients away from the upper gastrointestinal tract are more successful in producing weight loss and remission of T2DM than those that simply restrict stomach capacity. Although upper gastrointestinal tract bypass procedures alter the metabolic response to meal ingestion, by increasing early postprandial plasma concentrations of glucagon-like peptide 1 and insulin, it is not clear whether these effects make an important contribution to long-term control of glycemia and T2DM once substantial surgery-induced weight loss has occurred. Nonetheless, the effects of surgery on body weight and metabolic function indicate that bariatric surgery should be part of the standard therapy for T2DM. More research is needed to advance our understanding of the physiological effects of different bariatric surgical procedures and possible weight loss-independent factors that improve metabolic function and contribute to the resolution of T2DM.

Role of bariatric-metabolic surgery in the treatment of obese type 2 diabetes with body mass index <35 kg/m2: a literature review

Bariatric surgery has been used to treat type 2 diabetes mellitus (T2DM); however, its efficacy is still debatable. This literature review analyzed articles that evaluated the effects of bariatric surgery in treatment of T2DM in obese patients with a body mass index (BMI) of <35 kg/m(2). A paired t test was applied for the analysis of pre- and postintervention mean BMI, fasting plasma glucose (FPG), and glycosylated hemoglobin (A1c) values. A significant (P<0.001) reduction in BMI (from 29.95±0.51 kg/m(2) to 24.83±0.44 kg/m(2)), FPG (from 207.86±8.51 mg/dL to 113.54±4.93 mg/dL), and A1c (from 8.89±0.15% to 6.35±0.18%) was observed in 29 articles (n=675). T2DM resolution (A1c <7% without antidiabetes medication) was achieved in 84.0% (n=567) of the subjects. T2DM remission, control, and improvement were observed in 55.41%, 28.59%, and 14.37%, respectively. Only 1.63% (n=11) of the subjects presented similar or worse glycemic control after the surgery. T2DM remission (A1c <6% without antidiabetes medication) was higher after mini-gastric bypass (72.22%) and laparoscopic/Roux-en-Y gastric bypass (70.43%). According to the Foregut and Hindgut Hypotheses, T2DM results from the imbalance between the incretins and diabetogenic signals. The procedures that remove the proximal intestine and do ileal transposition contribute to the increase of glucagon-like peptide-1 levels and improvement of insulin sensitivity. These findings provide preliminary evidence of the benefits of bariatric-metabolic surgery on glycemic control of T2DM obese subjects with a BMI of <35 kg/m(2). However, more clinical trials are needed to investigate the metabolic effects of bariatric surgery in T2DM remission on pre-obese and obese class I patients.

Insulin resistance and bariatric surgery

The objective of this article is to systematically review the changes in insulin resistance after various types of bariatric surgical procedures. A Pubmed and EMBASE search for studies measuring insulin resistance before and after bariatric surgery was done and all original research articles from 1980 to present (2011) were included. Only the currently widely performed bariatric procedures were included. A meta-analysis of change in HOMA-IR was conducted, grouping studies with similar duration of follow-up. The percentage decrease in HOMA-IR at <=2 weeks, 1 month, 3 months, 6 months, 12 months and >16-18 months was found to be (mean ± standard error) -33.48 ± 5.78, -46.43 ± 6.99, -38.79 ± 9.64, -58.62 ± 7.38, -44.91 ± 7.98 and -67.04 ± 10.78%, respectively. RYGB (gastric bypass) and BPD (biliopancreatic diversion) produced a significant decrease in insulin resistance at 2 weeks after surgery, while LSG (sleeve gastrectomy) was strongly trending. LSG produced an earlier decrease in insulin resistance when compared to LAGB (gastric banding). RYGB, BPD and LSG produce an early decrease in insulin resistance through yet unknown mechanisms.