Clinical outcomes of single-stage versus two-stage laparoscopic Roux-en-y gastric bypass in the management of obesity (BMI ≥ 50 kg/m2): a retrospective cohort study.

BACKGROUND: Laparoscopic Roux-en-Y gastric bypass (LRYGB) in patients with obesity, BMI ≥ 50 kg/m2, can be a challenging operation. Weight loss with intra-gastric balloon (IGB) insertion prior to LRYGB may improve operative outcomes. METHODS: Between June 2000 and June 2020, patients with a BMI ≥ 50 kg/m2 underwent either IGB insertion followed by LRYGB (two-stage group), or LRYGB as the definitive bariatric procedure (single-stage group) in our institution. The two-stage procedure was adopted for high risk individuals. Primary outcome measures were percentage total weight loss (%TWL) at 24 months, length of stay and postoperative morbidity. Propensity score analysis was used to account for differences between groups. RESULTS: A total of 155 (mean age 42.9 years ± 10.60; mean BMI 54.6 kg/m2 ± 4.53) underwent either the two-stage (n = 30) or single-stage procedure (n = 125) depending on preoperative fitness. At 6 months following LRYGB, there was a significant difference in %TWL between the groups in a matched analysis (11.9% vs 23.7%, p < 0.001). At 24 months, there was no difference in %TWL (32.0% vs 34.7%, p = 0.13). Median hospital stay following LRYGB was 2.0 (1-4) days with the two-stage vs 2.0 (0-14) days for the single-stage approach (p = 0.75). There was also no significant difference in complication rates (p = 0.058) between the two groups. CONCLUSIONS: There was no difference in weight loss after one or two-stage procedures in the treatment of patients with a BMI ≥ 50 kg/m2 super obesity in a propensity score weighted analysis at 24 months. Length of stay and perioperative complications were similar for high risk patients; however, the two-stage approach was associated with delayed weight loss. Single-stage management is recommended for moderate risk patients, particularly with significant metabolic disorders, whilst two-stage approach is a safe and feasible pathway for high risk individuals.

Five-Year Outcomes of Bariatric Surgery vs. Conservative Weight Management in People with HIV: A Single-Center Tertiary Care Experience.

INTRODUCTION: Individuals with human immunodeficiency virus (HIV) infection now have life expectancies similar to non-infected people but face increased obesity prevalence. The long-term effects of bariatric surgery (BS) and conservative weight therapy (CWT) in patients living with HIV (PLWH) remain unexplored. METHODS: A retrospective review (2012-2018) at a Tertiary Centre for Bariatric Surgery and National Centre for HIV care examined the outcomes of BS and CWT. Parameters evaluated included weight loss and HIV metrics such as viral load and CD4 count. RESULTS: The study included 24 chronic HIV patients, with 10 undergoing BS (5 laparoscopic adjustable gastric banding (LAGB), 3 laparoscopic sleeve gastrectomy (LSG), 2 Roux-en-Y gastric bypass (LRYGB) and 14 in CWT. The BS group showed significant BMI reduction (- 7.07, - 6.55, - 7.81 kg/m2 at 1, 3, and 5 years). The CWT group's BMI reduction was non-significant. The BS group's %TWL was 16%, 17.8%, and 15% at 1, 3, and 5 years, respectively; however, stapled procedures were more effective, at 1 year, %TWL was 17% LSG and 25% RYGB, at 3 years, 23% LSG, 30% RYGB and at 5 years 21% with LSG and 28% with RYGB. HIV outcomes remained stable with undetectable viral loads in the BS group. DISCUSSION: BS appears to be a safe and effective medium-term treatment for obesity in PLWH, providing significant weight loss whilst maintaining the efficacy of HIV treatments. Although CWT has shown modest benefits, the outcomes from BS indicate that it could be a preferable option for managing obesity in PLWH based on this limited dataset.

Weight loss specific to indication, remission of diabetes, and short-term complications after sleeve gastrectomy conversion to Roux-en-Y gastric bypass: a systematic review and meta-analysis.

Laparoscopic sleeve gastrectomy (SG) is the most frequently performed bariatric procedure worldwide. Long-term complications such as insufficient weight loss (IWL) and gastroesophageal reflux disease (GERD) may necessitate SG conversion to Roux-en-Y gastric bypass (RYGB). The aim of this review was to determine the indication-specific weight loss and diabetes remission after SG conversion to RYGB (STOBY). Our objective was to extract all available published data on indication for conversion, weight loss, remission of diabetes, and short-term complications after STOBY. A systematic literature search was conducted to identify studies reporting outcomes following STOBY. A random effects model was used for meta-analysis. The search identified 44 relevant studies. Overall short-term (12-mo) excess weight loss (EWL) was 54.6% (95% confidence interval [CI], 46%-63%) in 23 studies (n = 712) and total weight loss (TWL) was 19.9% (95% CI, 14%-25%) in 21 studies (n = 740). For IWL, short-term (12-mo) pooled weight loss outcomes were 53.9% EWL (95% CI, 48%-59%) in 14 studies (n = 295) and 22.7% TWL (95% CI, 17%-28%) in 12 studies (n = 219), and medium-term (2-5 yr) outcomes were 45.8% EWL (95% CI, 38%-53%) in 7 studies (n = 154) and 20.6% TWL (95% CI, 15%-26%) in 9 studies (n = 206). Overall diabetes remission was 53% (95% CI, 33%-72%), and the perioperative complication rate was 8.2% (95% CI, 7.6%-8.7%). Revisional SG conversion to RYGB for IWL can achieve good weight loss outcomes and diabetes remission.

Gastrojejunal Anastomotic Technique. Does It Matter? Weight Loss and Weight Regain 5 Years After Laparoscopic Roux-en-Y Gastric Bypass.

PURPOSE: The gastrojejunostomy during laparoscopic Roux-en-Y gastric bypass (LRYGB) can be constructed by hand sewn (HSA), linear (LSA) and circular (CSA) stapler technique. They are all considered safe; however, it is not known which the best technique is. Short-term follow-up suggest no difference in weight loss or weight regain between them. However, there is no information on these parameters in the long term. Theatre time and cost are other important factors defining the best way to form gastrojejunostomy. MATERIALS AND METHODS: In a prospective longitudinal cohort study consecutive patients following primary LRYGB were recruited to a bariatric database in a tertiary care centre. Anastomotic technique, diameter, the length of operations and associated costs, weight loss and weight regain were recorded. Patients were followed up for 5 years. RESULTS: A total of 385 patients with an initial body mass index of 47.1 kg/m2 (35-68) were enrolled to this study. This decreased to 33.3 kg/m2 (21-54 kg/m2) after 5 years. There was no difference in %TWL after 3 years, P = 0.296, or 5 years, P = 0.187, between the techniques. The number of patients with weight regain was not different after 3 years, P = 0.224, or 5 years, P = 0.795. All techniques had similar operative time. CSA has a higher material cost. Early anastomotic stricture was more common following HSA; however, the difference was not significant. CONCLUSION: Mid-term weight loss and weight regain are not related to anastomotic technique, and there is no difference in operative time associated to them. Circular stapler technique has a higher material cost due to the additional stapler.

Management of Laryngotracheal Stenosis in Obesity. Is This Another Co-morbidity that Can Be Improved with Weight Loss Following Bariatric Surgery?

PURPOSE: Bariatric surgery improves several obesity-related comorbidities. Laryngotracheal stenosis is a rare condition that is usually managed with repeated endoscopic airway interventions and reconstructive airway surgery. The outcome of these definitive operations is worse in individuals with obesity. There are no studies investigating the effect of weight loss following bariatric surgery in the management of laryngotracheal stenosis. MATERIALS AND METHODS: In an observational study, consecutive patients with a BMI over 35 kg/m2 and laryngotracheal stenosis were prospectively recruited to a bariatric and airway stenosis database in two tertiary care centres. Patients were treated with laparoscopic Roux-en-Y gastric bypass or sleeve gastrectomy and control subjects were managed conservatively. RESULTS: A total of eleven patients with an initial body mass index of 43 kg/m2 (37-45) were enrolled to this study. Six patients underwent bariatric surgery and five subjects were treated conservatively. After 12 months, the total weight loss of patients undergoing bariatric surgery was 19.4% (14-24%) whilst 2.3% (1-3%) in the control group. The annual number of endoscopic airway interventions following bariatric surgery reduced (p = 0.002). Higher weight loss in patients led to less frequent interventions compared to control subjects (p = 0.004). Patients undergoing laryngotracheal reconstruction following bariatric surgery needed less endoscopic intervention, an annual average of 1.9 interventions before vs 0.5 intervention after. Conservatively managed control subjects required more frequent endoscopic intervention, 1.8 before vs 3.4 after airway reconstruction. CONCLUSION: Bariatric surgery reduced the number of endoscopic airway interventions and enabled patients to undergo successful definitive airway reconstructive surgery.

Small bowel obstruction due to retrograde intussusception after laparoscopic Roux-en-Y gastric bypass.

A 39-year-old female presented 4 years after laparoscopic Roux-en-Y gastric bypass with colicky abdominal pain, vomiting and inability to pass flatus. She had lost 100% of her excess weight after surgery and her body mass index had dropped from 46 to 22 kg/m(2). At exploration, a retrograde intussusception of the small bowel was noted distally to the jejunojejunostomy causing obstruction of the alimentary and biliopancreatic limb and gastric remnant. The intussusception was irreducible with signs of bowel ischaemia and required excision. The patient made an uneventful recovery. Colicky abdominal pain in a bariatric patient persisting more than 4 h mandates urgent investigation with abdominal computed tomography. Emergency care doctors should be aware of this specific complication in bariatric patients and seek expert advice.

Bariatric surgery waiting times in Canada.

BACKGROUND: Severe obesity is reaching epidemic proportions throughout the world, including Canada. The only permanent treatment of severe or morbid obesity is bariatric surgery. Access to bariatric surgery is very limited in Canada. We sought to collect accurate data on waiting times for the procedure. METHODS: We carried out a survey of members of the Canadian Association of Bariatric Physicians and Surgeons and performed a more detailed analysis within Quebec and at one Canadian bariatric surgery centre where a prospectively collected bariatric surgery registry has been maintained since 1983. RESULTS: The survey response rate was 85%. All centres determined whether patients were eligible for bariatric surgery based on the National Institutes of Health criteria. Patients entered the queue as "office contacts" and moved through the queue, with the exit point being completion of the procedure. In 2007, a total of 6783 patients were waiting for bariatric surgery and 1313 procedures were performed in Canada. Assuming these trends are maintained, the calculated average waiting time for bariatric surgery in Canada is just over 5 years (6783/1313). The Fraser Institute and the Wait Times Alliance benchmarks for reasonable surgical waiting times vary from 8 weeks for cancer surgery to 18 months for cosmetic surgery. At one Canadian centre, 12 patients died while waiting for bariatric surgery. CONCLUSION: The waiting times for bariatric surgery are the longest of any surgically treated condition. Given the significant reduction in the relative risk of death with bariatric surgery (40%-89% depending on the study), the current waiting times for the procedure in Canada are unacceptable.

Five-year outcomes of laparoscopic adjustable gastric banding and laparoscopic Roux-en-Y gastric bypass in a comprehensive bariatric surgery program in Canada.

BACKGROUND: Bariatric surgery remains the most effective modality to induce sustainable weight loss in the morbidly obese. Our aim was to compare outcomes between the laparoscopic Roux-en-Y gastric bypass (LRYGBP) and the laparoscopic adjustable gastric banding device (LAGBD) method with 5-year follow-up in a Canadian bariatric surgery centre. METHODS: This is a retrospective outcomes analysis of 1035 laparoscopic bariatric procedures performed over 7 years. We extracted data from our prospectively collected bariatric surgery registry from Feb. 1, 2002, to Jun. 30, 2008. We evaluated patient demographics, weight loss, complications, mortality and need for revision surgery by procedure type. RESULTS: We examined outcomes in 149 (14.4%) LAGBD and 886 (85.6%) LRYGBP procedures. The mean body mass index (BMI) was significantly higher in the LRYGBP group (50.9, standard deviation [SD] 8.9, v. 45.0, SD 6.7) whereas age and sex ratio were the same. There were 3 deaths (0.3%) in the LRYGBP group and no deaths in the LAGBD group. Sixteen patients (10.8%) in the LAGBD group needed conversion to LRYGBP because of poor weight loss, band intolerance, band erosion or slippage, and 6 patients (0.7%) in the LRYGBP group required revision because of inability to achieve the desired weight loss. The percent excess-weight loss was 41, 49, 59, 60 and 61 at 1, 2, 3, 4 and 5 years postsurgery for the LAGBD patients who kept their band, and 70, 79, 79, 79 and 75 for the LRYGBP patients. CONCLUSION: Laparoscopic weight loss surgery can be performed safely with acceptable mortality. Our study suggests superior weight loss and low revision requirement for the LRYGBP, making this a more durable procedure in a publicly funded health care system.

Bariatric surgery in individuals with human immunodeficiency virus and type 2 diabetes: a case series.

BACKGROUND: The efficacy and safety of bariatric surgery have not been fully elucidated in patients affected with human immunodeficiency virus. Although adjustable gastric banding and sleeve gastrectomy are starting to be used in patients with human immunodeficiency virus, there are limited descriptions of the outcomes of type 2 diabetes mellitus in individuals who are human immunodeficiency virus positive and undergoing these procedures. CASE PRESENTATION: We have evaluated retrospectively three patients who underwent adjustable gastric banding or sleeve gastrectomy, the effect in weight reduction and glycemic control as well as its impact on human immunodeficiency virus management. Case 1 (adjustable gastric banding), a 58-year-old Caucasian male, achieved 19% total weight loss, Case 2, a 33-year-old Caucasian male (sleeve gastrectomy) lost 25%, and Case 3, a 48-year-old Caucasian female (sleeve gastrectomy), lost 14% postoperation. In terms of type 2 diabetes mellitus, Case 2 achieved complete remission according to American Diabetes Association criteria, while Case 1 would also have achieved remission were it not for the continuation of metformin postoperatively. Insulin requirements and pill burden were markedly reduced in Case 3 after sleeve gastrectomy, although lack of remission was predictable given the longevity of type 2 diabetes mellitus and preoperative insulin dosage. In all three cases, human immunodeficiency virus status did not appear to be affected by the bariatric surgery which was supported by the postoperative stable CD4 count and undetectable viral load. CONCLUSIONS: Bariatric surgery is a safe and effective treatment modality in patients who are human immunodeficiency virus positive with obesity and type 2 diabetes mellitus.

Intragastric balloon outcomes in super-obesity: a 16-year city center hospital series.

BACKGROUND: Intragastric balloons represent an endoscopic therapy aimed at achieving weight loss by mechanical induction of satiety. Their exact role within the bariatric armamentarium remains uncertain. OBJECTIVE: Our study aimed to evaluate the use of intragastric balloon therapy alone and before definitive bariatric surgery over a 16-year period. SETTING: A large city academic bariatric center for super-obese patients. METHODS: Between January 2000 and February 2016, 207 patients underwent ORBERA intragastric balloon placement at esophagogastroduodenoscopy. Four surgeons performed the procedures, and data were entered prospectively into a dedicated bariatric database. Patients' weight loss data were measured through body mass index (BMI) and excess weight loss and recorded at each clinic review for up to 5 years (60 mo). Treatment arms included intragastric balloon alone with lifestyle therapy or intragastric balloon and definitive bariatric surgery: gastric banding, sleeve gastrectomy, or Roux-en-Y gastric bypass. An additional treatment arm of analysis included the overall results from intragastric balloon followed by stapled procedure. RESULTS: One hundred twenty-nine female and 78 male patients had a mean age of 44.5 (±11.3) years and a mean BMI of 57.3 (±9.7) kg/m2. Fifty-eight percent of patients suffered from type 2 diabetes. Time from initial or first balloon insertion to definitive surgical therapy ranged between 9 and 13 months. Seventy-six patients had intragastric balloon alone, and 131 had intragastric balloon followed by definitive procedure. At 60 months postoperatively the intragastric balloon alone with lifestyle changes demonstrated an excess weight loss of 9.04% and BMI drop of 3.8; intragastric balloon with gastric banding demonstrated an excess weight loss of 32.9% and BMI drop of 8.9. Intragastric balloon and definitive stapled procedure demonstrated a BMI drop of 17.6 and an excess weight loss of 52.8%. Overall, there were 3 deaths (1.4%), 2 within 10 days due to acute gastric perforation secondary to vomiting and 1 cardiac arrest at 4 weeks postoperatively. CONCLUSION: Intragastric balloons can offer effective weight loss in selected super-obese patients within a dedicated bariatric center offering multidisciplinary support. Balloon insertion alone offers only short-term weight loss; however, when combined with definitive bariatric surgical approaches, durable weight loss outcomes can be achieved. A strategy of early and continual vigilance for side effects and a low threshold for removal should be implemented. Surgeon and unit experience with intragastric balloons can contribute to "kick starting" successful weight loss as a bridge to definitive therapy in an established bariatric surgical pathway.

Bariatric Surgery or Non-surgical Weight Loss for Idiopathic Intracranial Hypertension? A Systematic Review and Comparison of Meta-analyses.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is associated with obesity and weight loss by any means is considered beneficial in this condition. OBJECTIVES: This study aims to appraise bariatric surgery vs. non-surgical weight-loss (medical, behavioural and lifestyle) interventions in IIH management. METHODS: A systematic review and meta-analyses of surgical and non-surgical studies. RESULTS: Bariatric surgery achieved 100% papilloedema resolution and a reduction in headache symptoms in 90.2%. Non-surgical methods offered improvement in papilloedema in 66.7%, visual field defects in 75.4% and headache symptoms in 23.2%. Surgical BMI decrease was 17.5 vs. 4.2 for non-surgical methods. CONCLUSIONS: Whilst both bariatric surgery and non-surgical weight loss offer significant beneficial effects on IIH symptomatology, future studies should address the lack of prospective and randomised trials to establish the optimal role for these interventions.

The Effects of Bariatric Surgery on Cardiac Structure and Function: a Systematic Review of Cardiac Imaging Outcomes.

BACKGROUND: Obesity is associated with cardiac dysfunction, atherosclerosis, and increased cardiovascular risk. It can be lead to obesity cardiomyopathy and severe heart failure, which in turn raise morbidity and mortality while carrying a negative impact on quality of life. There is increasing clinical and mechanistic evidence on the metabolic and weight loss effects of bariatric surgery on improving cardiac structure and function in obese patients. OBJECTIVES: The objective of this study was to quantify the effects of bariatric surgery on cardiac structure and function by appraising cardiac imaging changes before and after metabolic operations. METHODS: This is a comprehensive systematic review of studies reporting pre-operative and post-operative echocardiographic or magnetic resonance cardiac indices in obese patients undergoing bariatric surgery. Studies were quality scored, and data were meta-analyzed using random effects modeling. RESULTS: Bariatric surgery is associated with significant improvements in the weighted incidence of a number of cardiac indices including a decrease in left ventricular mass index (11.2%, 95% confidence intervals (CI) 8.2-14.1%), left ventricular end-diastolic volume (13.28 ml, 95% CI 5.22-21.34 ml), and left atrium diameter (1.967 mm, 95% CI 0.980-2.954). There were beneficial increases in left ventricular ejection fraction (1.198%, 95%CI -0.050-2.347) and E/A ratio (0.189%, 95%CI -0.113-0.265). CONCLUSIONS: Bariatric surgery offers beneficial cardiac effects on diastolic function, systolic function, and myocardial structure in obese patients. These may derive from surgical modulation of an enterocardiac axis. Future studies must focus on higher evidence levels to better identify the most successful bariatric approaches in preventing and treating the broad spectrum of obesity-associated heart disease while also enhancing treatment strategies in the management of obesity cardiomyopathy.

Type 1 Diabetes Mellitus and Bariatric Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND: Type 1 diabetes mellitus (T1DM) has a rising global prevalence. Although it is vastly outnumbered by type 2 diabetes mellitus rates, it remains a persistent worldwide source of morbidity and mortality. Increasingly, its sufferers are afflicted by obesity and its complications. The objective of the study is to quantify the effects of bariatric surgery on T1DM by appraising the primary outcomes of glycosylated haemoglobin (HbA1c), insulin requirements and body mass index (BMI). Secondary outcomes included blood pressure, triglycerides and cholesterol biochemistry. METHODS: A systematic review of studies reporting pre-operative and post-operative outcomes in T1DM patients undergoing bariatric surgery was done. Data were meta-analysed using random effects modelling. Subgroup analysis and quality scoring were assessed. RESULTS: Bariatric surgery in obese T1DM patients is associated with a significant reduction in insulin requirement (-48.95 units, 95 % CI of -56.27, -41.62), insulin requirement per kilogramme (-0.391, 95 % CI of -0.51, -0.27), HbA1c (-0.933, 95 % CI of -1.604, -0.262) and BMI (-11.04 kg/m(2), 95 % CI of -13.49, -8.59). Surgery is also associated with a statistically significant reduction in systolic and diastolic blood pressure and a significant beneficial rise in HDL. Heterogeneity in these results was high, and study quality was low overall. CONCLUSIONS: Bariatric surgery in obese T1DM patients is associated with a significant improvement in insulin requirement and a significant though modest effect on HbA1c. These early results require further substantiation with future studies focusing on higher levels of evidence. This may offer a deeper understanding of diabetogenesis and can contribute to better selection and stratification of diabetic patients for metabolic surgery and future metabolic treatment strategies.

Expression profiling of microdissected pancreatic adenocarcinomas.

Pancreatic ductal adenocarcinoma is characterized by a paucity of neoplastic cells embedded in a densely desmoplastic stroma. Therefore, laser capture microdissection was performed to obtain homogeneous populations of normal and neoplastic ductal cells. These were subjected to a comparative study of gene expression utilizing human cDNA arrays. A variety of dysregulated genes were identified, comprising cell cycle and growth regulators, invasion regulators, signalling and developmental molecules. In addition to genes already found to be overexpressed in pancreatic cancer, such as TIMP1, MMP7, CD59, rhoC and NDKA, we present evidence to implicate genes which have not previously been reported in this tumour type. These include the overexpressed genes ABL2, Notch4 and SOD1, as well as XRCC1, a DNA repair gene whose transcript was found downregulated. Quantitative real-time RT-PCR (QRT-PCR) was employed to confirm differential expression of ABL2, Notch4 and SOD1 and immunohistochemical analysis was used to verify decreased protein expression of XRCC1 using a custom-built pancreatic tissue array. Combining microarray-derived gene expression profiles of pure pancreatic cell populations, QRT-PCR and pancreas-specific tissue arrays therefore proved to be highly informative in elucidating the molecular pathology of this highly malignant tumour type.

Bariatric Surgery or Non-Surgical Weight Loss for Obstructive Sleep Apnoea? A Systematic Review and Comparison of Meta-analyses.

BACKGROUND: Obstructive sleep apnoea (OSA) is a well-recognised complication of obesity. Non-surgical weight loss (medical, behavioural and lifestyle interventions) may improve OSA outcomes, although long-term weight control remains challenging. Bariatric surgery offers a successful strategy for long-term weight loss and symptom resolution. OBJECTIVES: To comparatively appraise bariatric surgery vs. non-surgical weight loss interventions in OSA treatment utilising body mass index (BMI) and apnoea-hypopnoea index (AHI) as objective measures of weight loss and apnoea severity. METHODS: A systematic literature review revealed 19 surgical (n = 525) and 20 non-surgical (n = 825) studies reporting the primary endpoints of BMI and AHI before and after intervention. Data were meta-analysed using random effects modelling. Subgroup analysis, quality scoring and risk of bias were assessed. RESULTS: Surgical patients had a mean pre-intervention BMI of 51.3 and achieved a significant 14 kg/m(2) weighted decrease in BMI (95%CI [11.91, 16.44]), with a 29/h weighted decrease in AHI (95%CI [22.41, 36.74]). Non-surgical patients had a mean pre-intervention BMI of 38.3 and achieved a significant weighted decrease in BMI of 3.1 kg/m(2) (95%CI [2.42, 3.79]), with a weighted decrease in AHI of 11/h (95%CI [7.81, 14.98]). Heterogeneity was high across all outcomes. CONCLUSIONS: Both bariatric surgery and non-surgical weight loss may have significant beneficial effects on OSA through BMI and AHI reduction. However, bariatric surgery may offer markedly greater improvement in BMI and AHI than non-surgical alternatives. Future studies must address the lack of randomised controlled and comparative trials in order to confirm the exact relationship between metabolic surgery and non-surgical weight loss interventions in OSA resolution.

Bariatric surgery and nonalcoholic fatty liver disease.

The rising prevalence of nonalcoholic fatty liver disease (NAFLD) is associated with the increasing global pandemic of obesity. These conditions cluster with type II diabetes mellitus and the metabolic syndrome to result in obesity-associated liver disease. The benefits of bariatric procedures on diabetes and the metabolic syndrome have been recognized for some time, and there is now mounting evidence to suggest that bariatric procedures improve liver histology and contribute to the beneficial resolution of NAFLD in obese patients. These beneficial effects derive from a number of weight-dependent and weight-independent mechanisms including surgical BRAVE actions (bile flow changes, restriction of stomach size, anatomical gastrointestinal rearrangement, vagal manipulation, enteric hormonal modulation) and subsequent effects such as reduced lipid intake, adipocytokine secretion, modulation of gut flora, improvements in insulin resistance and reduced inflammation. Here, we review the clinical investigations on bariatric procedures for NAFLD, in addition to the mounting mechanistic data supporting these findings. Elucidating the mechanisms by which bariatric procedures may resolve NAFLD can help enhance surgical approaches for metabolic hepatic dysfunction and also contribute toward developing the next generation of therapies aimed at reducing the burden of obesity-associated liver disease.

Bariatric Surgery and Non-Alcoholic Fatty Liver Disease: a Systematic Review of Liver Biochemistry and Histology.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is becoming a leading cause of global liver disease that is associated with the rising prevalence of obesity worldwide. There is now increasing clinical and mechanistic evidence reporting on the metabolic and weight loss effects of bariatric surgery on improving NAFLD in obese patients. OBJECTIVES: The aim of this paper was to quantify the effects of bariatric surgery on NAFLD by appraising the modulation between pre- and post-operative liver enzyme levels (as markers of liver injury) and liver histology. METHODS: A systematic review of studies reporting pre-operative and post-operative liver enzymes or liver histology was done in obese patients with NAFLD undergoing bariatric surgery. Data were meta-analysed using random-effects modelling. Subgroup analysis, quality scoring and risk of bias were assessed. RESULTS: Bariatric surgery is associated with a significant reduction in the weighted incidence of a number of histological features of NAFLD including steatosis (50.2 and 95 %CI of 35.5-65.0), fibrosis (11.9 and 95 %CI of 7.4-16.3 %), hepatocyte ballooning (67.7 and 95 %CI 56.9-78.5) and lobular inflammation (50.7 and 95 %CI 26.6-74.8 %). Surgery is also associated with a reduction in liver enzyme levels, with statistically significant reductions in ALT (11.36 u/l, 95 %CI 8.36-14.39), AST (3.91 u/l, 95 %CI 2.23-5.59), ALP (10.55 u/l, 95 %CI 4.40-16.70) and gamma-GT (18.39 u/l, 95 %CI 12.62-24.16). Heterogeneity in results was high. CONCLUSIONS: Bariatric surgery is associated with a significant improvement in both histological and biochemical markers of NAFLD. Future studies must focus on higher levels of evidence to better identify the benefits of bariatric surgery on liver disease in order to enhance future treatment strategies in the management of NAFLD.