Obesity Drives STAT-1-Dependent NASH and STAT-3-Dependent HCC.

Obesity is a major driver of cancer, especially hepatocellular carcinoma (HCC). The prevailing view is that non-alcoholic steatohepatitis (NASH) and fibrosis or cirrhosis are required for HCC in obesity. Here, we report that NASH and fibrosis and HCC in obesity can be dissociated. We show that the oxidative hepatic environment in obesity inactivates the STAT-1 and STAT-3 phosphatase T cell protein tyrosine phosphatase (TCPTP) and increases STAT-1 and STAT-3 signaling. TCPTP deletion in hepatocytes promoted T cell recruitment and ensuing NASH and fibrosis as well as HCC in obese C57BL/6 mice that normally do not develop NASH and fibrosis or HCC. Attenuating the enhanced STAT-1 signaling prevented T cell recruitment and NASH and fibrosis but did not prevent HCC. By contrast, correcting STAT-3 signaling prevented HCC without affecting NASH and fibrosis. TCPTP-deletion in hepatocytes also markedly accelerated HCC in mice treated with a chemical carcinogen that promotes HCC without NASH and fibrosis. Our studies reveal how obesity-associated hepatic oxidative stress can independently contribute to the pathogenesis of NASH, fibrosis, and HCC.

Infrared photodesorption of CO from astrophysically relevant ices studied with a free-electron laser.

The infrared excitation and photodesorption of carbon monoxide (CO) and water-containing ices have been investigated using the FEL-2 free-electron laser light source at the FELIX laboratory, Radboud University, The Netherlands. CO-water mixed ices grown on a gold-coated copper substrate at 18 K were investigated. No CO photodesorption was observed, within our detection limits, following irradiation with light resonant with the C-O vibration (4.67 µm). CO photodesorption was seen as a result of irradiation with infrared light resonant with water vibrational modes at 2.9 µm and 12 µm. Changes to the structure of the water ice, which modifies the environment of the CO in the mixed ice, were also seen subsequent to irradiation at these wavelengths. No water desorption was observed at any wavelength of irradiation. Photodesorption at both wavelengths is due to a single-photon process. Photodesorption arises due to a combination of fast and slow processes of indirect resonant photodesorption (fast), and photon-induced desorption resulting from energy accumulation in the librational heat bath of the solid water (slow) and metal-substrate-mediated laser-induced thermal desorption (slow). Estimated cross-sections for the slow processes at 2.9 µm and 12 µm were found to be ∼7.5 × 10-18 cm2 and ∼4.5 × 10-19 cm2, respectively.

Long-term impact of weight loss for people with overweight but not obesity, and with type 2 diabetes: 10-year outcomes of a randomized trial of gastric band surgery.

AIM: Randomized trials reporting 5-year outcomes have shown bariatric surgery  to induce diabetes remission and improve cardiovascular risk. However, the longer-term effects of surgery are uncertain, with only one randomized trial reporting 10-year diabetes outcomes in people with obesity. We aimed to compare 10-year diabetes outcomes of people who are overweight but not obese, randomly assigned to receive either multidisciplinary diabetes care, or multidisciplinary diabetes care combined with gastric band (GB) surgery. METHODS: Between 2009 and 2011, 51 adults were randomized. After 5 years, they were discharged to receive community care and reassessed after 10 years. The primary outcome was diabetes remission, defined as glycated haemoglobin (HbA1c) <6.5% (48 mmol/mol) without glucose-lowering medication. RESULTS: Forty-one participants (20 medical and 21 GB) completed the 10-year assessment. The median (Q1, Q3) weight loss in the GB group was 9.8 (6.7, 16.3)% at 10 years compared with 5.6 (3.4, 7.6)% in the medical group (median difference 4.2%; p = .008). Diabetes remission occurred in five GB participants and no medical participants (relative risk 0.76, 95% CI: 0.55-0.93, p = .048). GB participants used fewer glucose-lowering medications at 10 years but HbA1c, fasting glucose, calculated cardiovascular risk, quality-of-life and incident diabetes complications did not differ significantly between the groups. CONCLUSION: When compared with medical care, GB surgery achieved greater weight loss and modestly increased the likelihood of diabetes remission. However, it did not improve HbA1c, cardiovascular risk or quality of life.

Malnutrition defined by GLIM criteria identifies a higher incidence of malnutrition and is associated with pulmonary complications after oesophagogastric cancer surgery, compared to ICD-10-defined malnutrition.

BACKGROUND & OBJECTIVES: Low muscle mass, measured using computed tomography (CT), is associated with poor surgical outcomes. We aimed to include CT-muscle mass in malnutrition diagnosis using the Global Leadership Initiative on Malnutrition (GLIM) criteria, compare it to the International Classification of Diseases 10th Revision (ICD-10) criteria, and assess the impact on postoperative outcomes after oesophagogastric (OG) cancer surgery. METHODS: One hundred and eight patients who underwent radical OG cancer surgery and had preoperative abdominal CT imaging were included. GLIM and ICD-10 malnutrition data were assessed against complication and survival outcomes. Low CT-muscle mass was determined using predefined cut-points. RESULTS: GLIM-defined malnutrition prevalence was significantly higher than ICD-10-malnutrition (72.2% vs. 40.7%, p < 0.001). Of the 78 patients with GLIM-defined malnutrition, low muscle mass (84.6%) was the predominant phenotypic criterion. GLIM-defined malnutrition was associated with pneumonia (26.9% vs. 6.7%, p = 0.010) and pleural effusions (12.8% vs. 0%, p = 0.029). Postoperative complications did not correlate with ICD-10 malnutrition. Severe GLIM (HR: 2.51, p = 0.014) and ICD-10 (HR: 2.15, p = 0.039) malnutrition were independently associated with poorer 5-year survival. CONCLUSIONS: GLIM criteria appear to identify more malnourished patients and more closely relate to surgical risk than ICD-10 malnutrition, likely due to incorporating objective muscle mass assessment.

Tubularized and Effaced Gastric Cardia Mimicking Barrett Esophagus Following Sleeve Gastrectomy: Protocolized Endoscopic and Histological Assessment With High-resolution Manometry Analysis.

OBJECTIVE: To describe expected endoscopic and histological changes at gastro-esophageal junction (GEJ) and define diagnostic paradigms for Barrett esophagus (BE) postsleeve gastrectomy (SG). SUMMARY BACKGROUND DATA: De novo incidence of BE post SG was reported as high as 18.8%. A confounding factor is the lack of standardized definition of BE post SG, which may differ from the general population due to procedure-induced alterations of GEJ. METHODS: Part 1 involved evaluating endoscopic changes of GEJ post SG (N = 567) compared to pre SG (N = 320), utilizing protocolized preoperative screening, postoperative surveillance and synoptic reporting. Part 2 involved dedicated studies examining causes of altered anatomical and mucosal GEJ appearance using histopathology (N = 55) and high-resolution manometry (HRM) (N = 15). RESULTS: Part 1 - A characteristic tubularized cardia segment projecting supra-diaphragmatically was identified and almost exclusive to post SG (0.6% vs.26.6%, P < 0.001). True BE prevalence was low (4.1%pre SG vs. 3.8%post SG, P = 0.756), esophagitis was comparable (32.1% vs. 25.9%, P = 0.056). Part 2 - Histologically-confirmed BE was found in 12/55 patients, but 70.8% had glandular-type gastric mucosa implying tubularized cardia herniation. HRM of tubularized cardia demonstrated concordance of supra-diaphragmatic cardia herniation between endoscopy and HRM (3 cm vs. 3.2 cm, P = 0.168), with frequent elevated isobaric intraluminal pressurizations in supra-and infra-diaphragmatic cardia compartments. CONCLUSION: A novel appearance of tubularized cardia telescoping supra-diaphragmatically with flattening of gastric folds is common post SG, likely associated with isobaric hyper-pressurization of proximal stomach. incidence of true BE post SG is low in short-intermediate term. These provided a clear framework for approaching endoscopic screening and surveillance, with correct anatomical and mucosal identifications, and clarified key issues of SG and BE.

Hospital costs and factors associated with days alive and at home after surgery (DAH30 ).

OBJECTIVE: To assess the relationships of patient and surgical factors and hospital costs with the number of days alive and at home during the 30 days following surgery (DAH30 ). DESIGN: Retrospective cohort study; analysis of Medibank Private health insurance hospital claims data, Australia, 1 January 2016 - 31 December 2017. SETTING, PARTICIPANTS: Admissions of adults (18 years or older) to hospitals for elective or emergency inpatient surgery with anaesthesia covered by private health insurance, Australia, 1 January 2016 - 31 December 2017. MAIN OUTCOME MEASURES: Associations between DAH30 and total hospital costs, and between DAH30 and surgery risk factors. RESULTS: Complete data were available for 126 788 of 181 281 eligible patients (69.9%); their median age was 62 years (IQR, 47-73 years), 72 872 were women (57%), and 115 117 had undergone elective surgery (91%). The median DAH30 was 27.1 days (IQR, 24.2-28.8 days), the median hospital cost per patient was $10 358 (IQR, $6624-20 174). The association between DAH30 and total hospital costs was moderate (Spearman ρ = -0.60; P < 0.001). Median DAH30 declined with age, comorbidity score, ASA physical status score, and surgical severity and duration, and was also lower for women. CONCLUSIONS: DAH30 is a validated, patient-centred outcome measure of post-surgical outcomes; higher values reflect shorter hospital stays and fewer serious complications, re-admissions, and deaths. DAH30 can be used to benchmark quality of surgical care and to monitor quality improvement programs for reducing the costs of surgical and other peri-operative care.

Salvage Treatment Using Anti-PD-1/CTLA-4 Immunotherapy After Failure of Neoadjuvant Chemotherapy in Microsatellite Instable Gastroesophageal Carcinoma.

Perioperative chemotherapy is standard treatment for patients with early high-risk gastroesophageal adenocarcinoma independent of molecular subtype. Approximately 8% of gastroesophageal cancers have a microsatellite instable phenotype (MSI-H), and retrospective analyses of neoadjuvant/adjuvant chemotherapy trials suggests no survival benefit in this patient population compared with surgery alone. Patients with advanced MSI-H malignancies obtain durable responses with immunotherapy using anti-programmed cell death protein 1 (PD-1) checkpoint blockade. We describe a case of a patient with an early MSI-H gastroesophageal adenocarcinoma who progressed on neoadjuvant chemotherapy precluding subsequent surgical resection. The patient was subsequently treated with immunotherapy using the anti-PD-1 antibody nivolumab and the anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody ipilimumab leading to a complete remission with biopsies of the residual tumor mass and regional lymph nodes revealing no residual tumor. This case highlights the lack of benefit from neoadjuvant chemotherapy in patients with MSI-H gastroesophageal cancers and suggests that perioperative anti-PD-1-based immunotherapy should be further investigated in this patient population. KEY POINTS: This report describes the successful salvage treatment of a patient with an early high-risk MSI-H gastroesophageal carcinoma who progressed through neoadjuvant chemotherapy using combination immunotherapy of the anti-programmed cell death protein 1 (PD-1) antibody nivolumab and the anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody ipilimumab, leading to an ongoing complete remission. The case is in keeping with retrospective analyses of perioperative treatment trials demonstrating a lack of chemotherapy benefit in patients with MSI-H gastroesophageal carcinoma and supports the further investigation of anti-PD-1-based immunotherapy as a treatment modality in this patient population. The case highlights the potential difficulties that may be encountered in the surgical management of patients treated with neoadjuvant immunotherapy with reactive dense fibrotic changes precluding surgical resection.

Evaluation of the histological variability of core and wedge biopsies in nonalcoholic fatty liver disease in bariatric surgical patients.

BACKGROUND: Liver biopsy remains the gold standard for characterizing and evaluating treatment response in nonalcoholic fatty liver disease (NAFLD). Liver heterogeneity and sampling variability can affect the reliability of results. This study aimed to compare histological variability of intraoperative wedge and core liver biopsies from different lobes in bariatric patients, to better inform surgeons on biopsy method and guide interpretation of results. METHODS: We prospectively recruited bariatric surgical patients. Intraoperative core biopsies were taken from the left and right lobe, with a wedge biopsy taken from the left. All biopsies were graded by a specialist liver pathologist, blinded to clinical details and biopsy site. Concordance of histological findings between sites was evaluated. RESULTS: There were 91 participants (72.2% female), mean age 46.8 ± 12.0 years, body mass index 45.9 ± 9.4 kg/m2. There was no significant pattern for up- or down-grading disease dependent on biopsy technique. Moderate to strong agreement was seen in the presence of NAFLD and nonalcoholic steatohepatitis (NASH, κ = 0.609-0.865, p < 0.001) between biopsy sites. Individual components (steatosis, inflammation, ballooning) showed weaker agreement (κ = 0.386-0.656, p < 0.01). Fibrosis showed particularly poor agreement (κ = 0.223-0.496, p < 0.01). Detection of pathology improved with a combination of biopsy techniques, compared to a single biopsy method. CONCLUSION: Overall diagnosis of NAFLD or NASH shows good agreement between biopsy sites, but individual components, particularly fibrosis stage, vary significantly. Clinicians should consider biopsies from varied sites, to better assess liver disease severity. These data have important implications in fibrosis assessment of NAFLD and are relevant in the interpretation of histological efficacy of investigational pharmacotherapies. TRIAL REGISTRATION: ACTRN12615000875505 (Australian Clinical Trials Register).

A new technique for determining the refractive index of ices at cryogenic temperatures.

A reflection-absorption optical (RAO) spectrometer, operating across the ultra-violet/visible (UV/visible) wavelength region, has been developed that allows simultaneous measurements of optical properties and thickness of thin solid films at cryogenic temperatures in ultrahigh vacuum. The RAO spectrometer enables such measurements to be made after ice deposition, as opposed to most current approaches which make measurements during deposition. This allows changes in the optical properties and in the thickness of the film to be determined subsequent to thermal, photon or charged particle processing. This is not possible with current techniques. A data analysis method is presented that allows the wavelength dependent n and k values for ices to be extracted from the reflection-absorption spectra. The validity of this analysis method is shown using model data from the literature. New data are presented for the reflection UV/visible spectra of amorphous and crystalline single component ices of benzene, methyl formate and water adsorbed on a graphite surface. These data show that, for benzene and methyl formate, the crystalline ice has a larger refractive index than amorphous ice, reflecting changes in the electronic environment occurring in the ice during crystallisation. For water, the refractive index does not vary with ice phase.

A systematic review: Current trends and take rates of cultured epithelial autografts in the treatment of patients with burn injuries.

Several issues persist in clinical translation and application of cultured epithelial autografts during treatment of patients with massive burn injuries. The aim of this systematic review is to determine (1) current practice and trends in clinical application and (2) clinical efficacy of cultured epithelial autografts. A structured literature search was performed in Ovid MEDLINE from 1946 and Ovid EMBASE from 1974 until present. All published peer-reviewed randomized or non-randomized clinical studies, cohort studies, prospective, or retrospective series involving human application of cultured epithelial autografts in the setting of burn injury were included. From 7,267 studies initially identified, 77 studies were included in the analysis. In 96% (74/77) of these series, the sample size was less than 100 patients. In 76.6% (59/77) publications, average burn treated exceeded 40% total body surface area. Overall, cultured epithelial autograft take rates reported in the literature were inconsistent and varied significantly from 0 to 100%. There was a recent trend for co-application of cultured grafts with autologous skin grafts, achieving relatively high and consistent take rates of 73-96%. Results from cultured epithelial autograft application remained unpredictable. This technology remains an adjunct or biological dressing, and not an alternative to conventional split skin graft. However, it has contributed to wound closure and it has been life saving in selected circumstances. Skin tissue engineering should continue as the clinical need for skin replacement is foreseeable into the future.

Evaluating feasibility and accuracy of non-invasive tests for nonalcoholic fatty liver disease in severe and morbid obesity.

INTRODUCTION: In obese individuals, nonalcoholic fatty liver disease (NAFLD) is common but often goes undiagnosed, and therefore untreated. The presence of significant fibrosis is a key determinant of NAFLD progression, and liver steatosis has substantial cardiovascular implications. We aimed to determine the diagnostic accuracy of common noninvasive diagnostic tests for steatosis and fibrosis in the obese. METHODS: We recruited 182 severely and morbidly obese individuals undergoing bariatric surgery (age 44 ± 12 years, body mass index 45.1 ± 8.3 kg/m2). Medical history, blood tests and liver biopsy were taken on the day of surgery. Serum steatosis and fibrosis scores were calculated. In a subgroup of patients, transient elastography with controlled attenuation parameter (TE/CAP) (n = 82) and proton magnetic resonance spectroscopy (1H-MRS) (n = 49) were performed. RESULTS: 1H-MRS had excellent diagnostic accuracy for steatosis, with strong correlation to steatosis (r = 0.647, p < 0.001), good AUROC (0.852, p = 0.001), sensitivity (81.3%) and specificity (87.5%). However, due to low feasibility in this cohort (65.3% success), this was substantially decreased with intention-to-diagnose analysis (sensitivity 50.0%, specificity 60.9%). CAP had good feasibility (80.5%), and performed better in intention-to-diagnose analysis (AUROC 0.688, sensitivity 84.8%, specificity 47.2%). Serum steatosis scores performed poorly, with comparable accuracy to ALT. For significant fibrosis, TE had the best accuracy (AUROC 0.903, p = 0.007), which remained reasonable after intention-to-diagnose analysis (sensitivity 100%, specificity 59.0%). A combination approach using CAP with ALT for steatosis and TE with Forn index for fibrosis yielded reasonable overall accuracy. CONCLUSIONS: 1H-MRS and TE/CAP had greatest accuracy for NAFLD-related steatosis and fibrosis. Failure rates in obesity significantly diminished diagnostic ability. Use of a combination of serum and imaging tests improved overall feasibility of assessment and diagnostic accuracy in obese individuals.

A TPD and RAIRS comparison of the low temperature surface behavior of benzene, toluene, and xylene on graphite.

The first comparative study of the surface behavior of four small aromatic molecules, benzene, toluene, p-xylene, and o-xylene, adsorbed on graphite at temperatures ≤30 K, is presented. Intermolecular interactions are shown to be important in determining the growth of the molecules on the graphite surface at low (monolayer) exposures. Repulsive intermolecular interactions dominate the behavior of benzene and toluene. By contrast, stronger interactions with the graphite surface are observed for the xylene isomers, with islanding observed for o-xylene. Multilayer desorption temperatures and energies increase with the size of the molecule, ranging from 45.5 to 59.5 kJ mol-1 for benzene and p-xylene, respectively. Reflection absorption infrared spectroscopy gives insight into the effects of thermal processing on the ordering of the molecules. Multilayer benzene, p-xylene, and o-xylene form crystalline structures following annealing of the ice. However, we do not observe an ordered structure for toluene in this study. The ordering of p-xylene shows a complex relationship dependent on both the annealing temperature and exposure.

Peeling the astronomical onion.

Water ice is the most abundant solid in the Universe. Understanding the formation, structure and multiplicity of physicochemical roles for water ice in the cold, dense interstellar environments in which it is predominantly observed is a crucial quest for astrochemistry as these are regions active in star and planet formation. Intuitively, we would expect the mobility of water molecules deposited or synthesised on dust grain surfaces at temperatures below 50 K to be very limited. This work delves into the thermally-activated mobility of H2O molecules on model interstellar grain surfaces. The energy required to initiate this process is studied by reflection-absorption infrared spectroscopy of small quantities of water on amorphous silica and highly oriented pyrolytic graphite surfaces as the surface is annealed. Strongly non-Arrhenius behaviour is observed with an activation energy of 2 kJ mol-1 on the silica surface below 25 K and 0 kJ mol-1 on both surfaces between 25 and 100 K. The astrophysical implication of these results is that on timescales shorter than that estimated for the formation of a complete monolayer of water ice on a grain, aggregation of water ice will result in a non-uniform coating of water, hence leaving bare grain surface exposed. Other molecules can thus be formed or adsorbed on this bare surface.

Adsorption and Thermal Processing of Glycolaldehyde, Methyl Formate, and Acetic Acid on Graphite at 20 K.

We present the first detailed comparative study of the adsorption and thermal processing of the three astrophysically important C2O2H4 isomers glycolaldehyde, methyl formate, and acetic acid adsorbed on a graphitic grain analogue at 20 K. The ability of the individual molecule to form intermolecular hydrogen bonds is extremely important, dictating the growth modes of the ice on the surface and the measured desorption energies. Methyl formate forms only weak intermolecular bonds and hence wets the graphite surface, forming monolayer, bilayer, and multilayer ices, with the multilayer having a desorption energy of 35 kJ mol(-1). In contrast, glycolaldehyde and acetic acid dewet the surface, forming clusters even at the very lowest coverages. The strength of the intermolecular hydrogen bonding for glycolaldehyde and acetic acid is reflected in their desorption energies (46.8 and 55 kJ mol(-1), respectively), which are comparable to those measured for other hydrogen-bonded species such as water. Infrared spectra show that all three isomers undergo structural changes as a result of thermal processing. In the case of acetic acid and glycolaldehyde, this can be assigned to the formation of well-ordered, crystalline, structures where the molecules form chains of hydrogen-bonded moieties. The data reported here are of relevance to astrochemical studies of hot cores and star-forming regions and can be used to model desorption from interstellar ices during the warm up phase with particular importance for complex organic molecules.

Trapping and desorption of complex organic molecules in water at 20 K.

The formation, chemical, and thermal processing of complex organic molecules (COMs) is currently a topic of much interest in interstellar chemistry. The isomers glycolaldehyde, methyl formate, and acetic acid are particularly important because of their role as pre-biotic species. It is becoming increasingly clear that many COMs are formed within interstellar ices which are dominated by water. Hence, the interaction of these species with water ice is crucially important in dictating their behaviour. Here, we present the first detailed comparative study of the adsorption and thermal processing of glycolaldehyde, methyl formate, and acetic acid adsorbed on and in water ices at astrophysically relevant temperatures (20 K). We show that the functional group of the isomer dictates the strength of interaction with water ice, and hence the resulting desorption and trapping behaviour. Furthermore, the strength of this interaction directly affects the crystallization of water, which in turn affects the desorption behaviour. Our detailed coverage and composition dependent data allow us to categorize the desorption behaviour of the three isomers on the basis of the strength of intermolecular and intramolecular interactions, as well as the natural sublimation temperature of the molecule. This categorization is extended to other C, H, and O containing molecules in order to predict and describe the desorption behaviour of COMs from interstellar ices.

Laparoscopic adjustable gastric banding and progression from impaired fasting glucose to diabetes.

AIMS/HYPOTHESIS: Obesity and dysglycaemia are major risk factors for type 2 diabetes. We determined if obese people undergoing laparoscopic adjustable gastric banding (LAGB) had a reduced risk of progressing from impaired fasting glucose (IFG) to diabetes. METHODS: This was a retrospective cohort study of obese people with IFG who underwent LAGB. Weight and diabetes outcomes after a minimum follow-up period of 4 years (mean ± SD 6.1 ± 1.7 years) were compared with those of Australian adults with IFG from a population-based study (AusDiab). RESULTS: We identified 281 LAGB patients with baseline IFG. Their mean ± SD age and BMI were 46 ± 9 years and 46 ± 9 kg/m(2), respectively. The diabetes incidence for patients in the lowest, middle and highest weight loss tertile were 19.1, 3.4 and 1.8 cases/1,000 person-years, respectively. The AusDiab cohort had a lower BMI (28 ± 5 kg/m(2)) and a diabetes incidence of 12.5 cases/1,000 person-years. This increased to 20.5 cases/1,000 person-years when analysis was restricted to the 322 obese AusDiab participants, which was higher than the overall rate of 8.2 cases/1,000 person-years seen in the LAGB group (p = 0.02). Multivariable analysis of the combined LAGB and AusDiab data suggested that LAGB was associated with ∼75% lower risk of diabetes (OR 0.24 [95% CI 0.10, 0.57], p = 0.004). CONCLUSIONS/INTERPRETATION: In obese people with IFG, weight loss after LAGB is associated with a substantially reduced risk of progressing to diabetes over ≥4 years. Bariatric surgery may be an effective diabetes prevention strategy in this population.

Robotic versus laparoscopic gastric bypass in bariatric surgery: a systematic review and meta-analysis on perioperative outcomes.

BACKGROUND: Robotic-assisted surgery has emerged as a compelling approach to bariatric surgery. However, current literature has not consistently demonstrated superior outcomes to laparoscopic bariatric surgery to justify its higher cost. With its mechanical advantages, the potential gains from the robotic surgical platform are likely to be apparent in more complex cases such as gastric bypass, especially revisional cases. OBJECTIVE: This systematic review and meta-analysis aimed to summarize the literature and evaluate the peri-operative outcomes of patients with obesity undergoing robotic gastric bypass versus laparoscopic gastric bypass surgery. SETTING: Systematic review. METHODS: A literature search of Embase, Medline, Pubmed, Cochrane library, and Google Scholar was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies comparing outcomes of robotic and laparoscopic gastric bypass for obesity were included. RESULTS: Twenty-eight eligible studies comprised a total of 82,155 patients; 9051 robotic bypass surgery (RBS) versus 73,104 laparoscopic bypass surgery (LBS) were included. All included studies compared Roux-en-Y gastric bypass. RBS was noted to have higher reoperation rate within 30 days (4.4% versus 3.4%; odds ratio 1.31 [95% CI, 1.04-1.66]; P = .027; I2 = 43.5%) than LBS. All other endpoints measured (complication rate, anastomotic leak, anastomotic stricture, surgical site infections, hospital readmission, length of stay, operative time, conversion rate and mortality) did not show any difference between RBS and LBS. CONCLUSION: This systematic review and meta-analysis showed that there was no significant difference in key outcome measures in robotic versus laparoscopic gastric bypass. RBS was associated with a slightly higher reoperation rate and there was no reduction in overall complication rate with the use of robotic platform.