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Aims/hypothesis: Roux-en-Y gastric bypass surgery (RYGB) frequently results in remission of type 2 diabetes as well as exaggerated secretion of glucagon-like peptide-1 (GLP-1). Here, we assessed RYGB-induced transcriptomic alterations in the small intestine and investigated how they were related to the regulation of GLP-1 production and secretion in vitro and in vivo., Methods: Human jejunal samples taken perisurgically and 1 year post RYGB (n=13) were analysed by RNA-seq. Guided by bioinformatics analysis we targeted four genes involved in cholesterol biosynthesis, which we confirmed to be expressed in human L cells, for potential involvement in GLP-1 regulation using siRNAs in GLUTag and STC-1 cells. Gene expression analyses, GLP-1 secretion measurements, intracellular calcium imaging and RNA-seq were performed in vitro. OGTTs were performed in C57BL/6j and iScd1 -/- mice and immunohistochemistry and gene expression analyses were performed ex vivo., Results: Gene Ontology (GO) analysis identified cholesterol biosynthesis as being most affected by RYGB. Silencing or chemical inhibition of stearoyl-CoA desaturase 1 (SCD1), a key enzyme in the synthesis of monounsaturated fatty acids, was found to reduce Gcg expression and secretion of GLP-1 by GLUTag and STC-1 cells. Scd1 knockdown also reduced intracellular Ca 2+ signalling and membrane depolarisation. Furthermore, Scd1 mRNA expression was found to be regulated by NEFAs but not glucose. RNA-seq of SCD1 inhibitor-treated GLUTag cells identified altered expression of genes implicated in ATP generation and glycolysis. Finally, gene expression and immunohistochemical analysis of the jejunum of the intestine-specific Scd1 knockout mouse model, iScd1 -/- , revealed a twofold higher L cell density and a twofold increase in Gcg mRNA expression., Conclusions/interpretation: RYGB caused robust alterations in the jejunal transcriptome, with genes involved in cholesterol biosynthesis being most affected. Our data highlight SCD as an RYGB-regulated L cell constituent that regulates the production and secretion of GLP-1., (© 2023. The Author(s).)

Bariatric surgery is an efficient method to induce weight loss and also, frequently, remission of type 2 diabetes (T2D). Unpaired studies have shown bariatric surgery and dietary interventions to differentially affect multiple hormonal and metabolic parameters, suggesting that bariatric surgery causes T2D remission at least partially via unique mechanisms. In the current study, plasma metabolite profiling was conducted in patients with ( n = 10) and without T2D ( n = 9) subjected to Roux-en-Y gastric bypass surgery (RYGB). Mixed-meal tests were conducted at baseline, after the presurgical very-low-calorie diet (VLCD) intervention, immediately after RYGB, and after a 6-week recovery period. Thereby, we could compare fasted and postprandial metabolic consequences of RYGB and VLCD in the same patients. VLCD yielded a pronounced increase in fasting acylcarnitine levels, whereas RYGB, both immediately and after a recovery period, resulted in a smaller but opposite effect. Furthermore, we observed profound changes in lipid metabolism following VLCD but not in response to RYGB. Most changes previously associated with RYGB were found to be consequences of the presurgical dietary intervention. Overall, our results question previous findings of unique metabolic effects of RYGB and suggest that the effect of RYGB on the metabolite profile is mainly attributed to caloric restriction., (© 2020 by the American Diabetes Association.)

Background: Obesity-related diseases cause costs to society. We studied the cost of work absenteeism before and after gastric bypass and the effects of postoperative diabetes resolution., Patients and Methods: Data were obtained from the Scandinavian Obesity Surgery Registry (SOReg) (national coverage >98%) and cross-matched with data from the Social insurance Agency (coverage 100%) for the period ±3 years from operation. In 2010, a total of 7454 bariatric surgeries were performed; the study group is 4971 unique individuals with an annual income of >10,750 Euros and complete data sets. A sex-, age-, and income-matched reference population was identified for comparison., Results: Patients with obesity had preoperatively a 3.5-fold higher absenteeism. During follow-up (FU), the ratio relative to the reference population remained constant. An increase of 12-14 net absenteeism days was observed in the first 3 months after surgery. Female sex (OR 1.5, CI 1.13-1.8), preoperative anti-depressant use (OR 1.5, CI 1.3-1.9), low income (OR 1.4, CI 1.2-1.8), and a history of sick leave (OR 1.004, CI 1.003-1.004) were associated with increased absenteeism during FU. Diabetes resolution did not decrease absenteeism from preoperative values., Conclusions: Patients with obesity have higher preoperative absenteeism than the reference population. Operation caused an increase the first 90 days after surgery of 12-13 days. There were no relative increases in absenteeism in the next 3 years; patients did not deviate from preoperative patterns but followed the trend of the reference population. Preoperative diabetes did not elevate that level during FU; diabetes resolution did not lower absenteeism.

Background: Internal hernia (IH) is a common complication of laparoscopic Roux-en-Y gastric bypass (LRYGB). Little large-volume data exist on how to handle the mesenteric defects during LRYGB. This study evaluated long-term follow-up (5.5 years) of 2443 patients with primary closure of the mesenteric defects with a stapling device at LRYGB, in comparison with a non-closed group from the same centre., Methods: All patients (N = 4013) undergoing LRYGB over a 10-year period (2005-2015) at a single institution were evaluated. The mesenteric defects were routinely closed starting June 2010. In total, 1570 non-closure patients and 2443 patients with stapled closure of the defects were prospectively entered and the results analysed., Results: Closure of the mesenteric defects increased surgical time by 4 min and did not affect the 30-day complication rate. IH incidence was significantly lower (2.5%) in the closure group compared with 11.7% in the non-closure group, at 60 months. The relative risk reduction by closing the mesenteric defects was 4.09-fold (95% CI = 2.97-5.62) as calculated using a survival model., Conclusions: Internal hernia after LRYGB occurs frequently if mesenteric defects are left unclosed. Primary closure with a hernia-stapling device is safe and significantly reduces the risk of internal hernia.

Objective: To evaluate effect on comorbid disease and weight loss 5 years after Roux-en-Y gastric bypass (RYGB) surgery for morbid obesity in a large nationwide cohort., Background: The number patients having surgical procedures to treat obesity and obesity-related disease are increasing. Yet, population-based, long-term outcome studies are few., Methods: Data on 26,119 individuals [75.8% women, 41.0 years, and body mass index (BMI) 42.8 kg/m] undergoing primary RYGB between May 1, 2007 and June 30, 2012, were collected from 2 Swedish quality registries: Scandinavian Obesity Surgery Registry and the Prescribed Drug Registry. Weight, remission of type 2 diabetes mellitus, hypertension, dyslipidemia, depression, and sleep apnea, and changes in corresponding laboratory data were studied. Five-year follow-up was 100% (9774 eligible individuals) for comorbid diseases., Results: BMI decreased from 42.8 ± 5.5 to 31.2 ± 5.5 kg/m at 5 years, corresponding to 27.7% reduction in total body weight. Prevalence of type 2 diabetes mellitus (15.5%-5.9%), hypertension (29.7%-19.5%), dyslipidemia (14.0%-6.8%), and sleep apnea (9.6%-2.6%) was reduced. Greater weight loss was a positive prognostic factor, whereas increasing age or BMI at baseline was a negative prognostic factor for remission. The use of antidepressants increased (24.1%-27.5%). Laboratory status was improved, for example, fasting glucose and glycated hemoglobin decreased from 6.1 to 5.4 mmol/mol and 41.8% to 37.7%, respectively., Conclusions: In this nationwide study, gastric bypass resulted in large improvements in obesity-related comorbid disease and sustained weight loss over a 5-year period. The increased use of antidepressants warrants further investigation.

Background: A growing body of literature on Roux-en-Y gastric bypass surgery (RYGB) has generated inconclusive results on the mechanism underlying the beneficial effects on weight loss and glycaemia, partially due to the problems of designing clinical studies with the appropriate controls. Moreover, RYGB is only performed in obese individuals, in whom metabolism is perturbed and not completely understood., Methods: In an attempt to isolate the effects of RYGB and its effects on normal metabolism, we investigated the effect of RYGB in lean pigs, using sham-operated pair-fed pigs as controls. Two weeks post-surgery, pigs were subjected to an intravenous glucose tolerance test (IVGTT) and circulating metabolites, hormones and lipids measured. Bile acid composition was profiled after extraction from blood, faeces and the gallbladder., Results: A similar weight development in both groups of pigs validated our experimental model. Despite similar changes in fasting insulin, RYGB-pigs had lower fasting glucose levels. During an IVGTT RYGB-pigs had higher insulin and lower glucose levels. VLDL and IDL were lower in RYGB- than in sham-pigs. RYGB-pigs had increased levels of most amino acids, including branched-chain amino acids, but these were more efficiently suppressed by glucose. Levels of bile acids in the gallbladder were higher, whereas plasma and faecal bile acid levels were lower in RYGB- than in sham-pigs., Conclusion: In a lean model RYGB caused lower plasma lipid and bile acid levels, which were compensated for by increased plasma amino acids, suggesting a switch from lipid to protein metabolism during fasting in the immediate postoperative period.

Objective: To study the immediate effects of Roux-en-Y gastric bypass (RYGB) on glucose homeostasis, insulin, and incretin responses to mixed-meal tests compared with the effects of calorie restriction (CR)., Setting: University-affiliated bariatric surgery clinic., Background: RYGB induces remission of type 2 diabetes (T2D) long before significant weight loss occurs. The time course and underlying mechanisms of this remission remain enigmatic. A prevailing theory is that secretory patterns of incretin hormones are altered due to rearrangement of the gastrointestinal tract. To what extent reduced calorie intake contributes to the remission of T2D is unknown., Methods: Nine normoglycemic patients and 10 T2D patients were subjected to mixed-meal tests (MMT) 4 weeks before surgery before initiation of a very low calorie diet regimen (MMT -4 w ), 1 day before surgery on a very low calorie diet regimen (MMT -1 d ), on the morning of the first day after surgery (MMT +1 d ; first postsurgical meal), and 6 weeks after surgery (MMT +6 w ). Insulin, glucose, active glucagon-like peptide 1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP) were measured., Results: CR lowered insulin in T2D patients, whereas glucose, GIP, and GLP-1 were unaffected. RYGB immediately increased plasma insulin and GIP. The GLP-1 response was delayed compared with the GIP response. T2D patients exhibited lower insulin responses after RYGB compared with normoglycemic patients. GIP responses were similar in both groups at all occasions, whereas T2D patients displayed markedly elevated GLP-1 responses 6 weeks after RYGB. Glucose was unaffected by CR and RYGB in both groups. Insulin sensitivity was unaffected by CR but improved with RYGB., Conclusion: RYGB exerts powerful and immediate effects on insulin and incretin responses to food, independently of changes caused by CR., (Copyright © 2017 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.)

Background: High intraabdominal pressure (IAP) during laparoscopic surgery has been associated with postoperative discomfort. Effects on nausea and access have not been subjected to randomized studies. In cholecystectomy, lower IAP may cause less pain, but nausea and surgical access in RYGB surgery have not been investigated. We studied the influence of two IAP levels on surgical access, operation time, postoperative pain, and nausea., Methods: Fifty consecutive female gastric bypass patients were randomized to intraabdominal pressure of 12 (IAP12) or 18 (IAP18) mm Hg. Surgeons and personnel were blinded to randomization; study groups were well matched for age and BMI. Operative time was noted in minutes. Visual analogue scales were used for assessing access and for patients assessing pain (abdomen-shoulder) and nausea (supine-standing) at six time points during the first 16 postoperative hours. Rescue medication was recorded., Results: In 3/25 patients in the IAP12 group, the code was broken due to access problems vs. 0/25 in the IAP18 group (p = 0.1398). Operative time did not differ. Access was significantly better for IAP18 (92.2 ± 2.3 vs. 69.3 ± 4.2; p = 0.0001). Postoperative shoulder pain was maximal after 6 h but throughout less than in the abdomen (p < 0.0001); there were no differences in pain between IAP18 and IAP12 (p = 0.7408). Postoperative nausea was significantly greater standing than supine but without differences between groups., Conclusion: Higher IAP gives better surgical access in laparoscopic Roux-en-Y gastric bypass with no negative effect on pain or nausea.

Background: Postoperative nausea and vomiting (PONV) is common after general anaesthesia, and corticosteroids are used in many protocols for enhanced recovery after surgery (ERAS). However, surgical techniques are developing, and ERAS protocols need to be reevaluated from time to time., Patients and Method: In this study, we compared the effects of oral vs. parenteral corticosteroid administration on postoperative nausea. Elective Roux-y-gastric bypass (RYGB) patients were randomly assigned to either 8 mg betamethasone orally (n = 50) or parentally (n = 25) or as controls (n = 25), in a double-blind design. PONV risk factors were noted. All patients had the same anaesthetic technique. Data were collected at baseline, on arrival to the recovery room (RR) and at five more time points during the first 24 h. Nausea and tiredness were patient assessed using visual analogue scales; rescue drug consumption was recorded., Results: Operation time was 30-40 min. Neither demographics nor risk factors for nausea differed between groups. Neither peak values for nor total amount of nausea differed between groups. The number of supplemental injections was the same for all groups., Comments: In a setting of modern laparoscopic RYGB, the value of betamethasone in preventing PONV seems to be limited. ERAS protocols may need re-evaluation.

Background: Many patients experience postoperative nausea and vomiting (PONV). Preoperative treatment with carbohydrate solutions seems to improve the course after different types of surgery. This study was undertaken to investigate the potential value of different models for preoperative hydration/nutrition, in addition to our ERAS (enhanced recovery after surgery) protocol., Methods: Ninety non-diabetic women planned for elective laparoscopic gastric bypass and aged 18-65 years were included. All were on preoperative low-calorie diet (LCD). They were randomized into three arms, either a carbohydrate-rich drink, a protein-enriched drink, or tap water and instructed to drink 800 and 200 mL 16 and 2 h, respectively, prior to operation. Risk factors for PONV were recorded preoperatively. All patients were operated before lunch and received 1500-2000 mL of Ringer-Acetate solution during the 24-30-h postoperative hospital time. Four variables (nausea, pain, tiredness, and headache) were registered on 100-mm visual analog scales six times over 22 h. The need for additional medication was registered., Results: Out of 90 patients, 73 complete datasets were obtained. Nausea peaked at 7 p.m. but with no statistically significant differences between groups for any of the variables. Pain peaked the first 2 h postoperatively, remained longer, and had not returned to baseline values at 6 a.m. the morning after surgery but with no difference between groups., Conclusions: Inside our ERAS protocol, additional preoperative carbohydrate- or protein-enriched fluid treatment did not further reduce immediate patient discomfort in laparoscopic gastric bypass surgery.

Gastric bypass (GBP) results in rapid type 2 diabetes (T2D) remission in most cases. Consequences of GBP reversal are unknown. A GBP-operated T2D patient was given mixed-meal tests before (MMTpre), 2 months (MMT2-M) and 12 months (MMT12-M) after GBP reversal. Glucose, hormones and metabolite profiles were assessed. MMT2-M displayed slightly lower glucose levels; MMT12-M displayed higher glucose and insulin levels, indicating deteriorating glycaemia. Homeostasis model assessment (HOMA)-β was higher at MMT2-M, but reduced at MMT12-M. Matsuda index revealed slightly reduced insulin sensitivity at MMT2-M, which deteriorated further at MMT12-M. Markers for metabolic stress and insulin resistance were elevated at MMT12-M. Gastric inhibitory polypeptide (GIP) levels were increased at MMT2-M and decreased at MMT12-M. Glucagon-like peptide-1 (GLP-1) decreased at MMT2-M and further decreased at MMT12-M. In conclusion, in this patient, GBP reversal provoked deteriorating glycaemia and long-term development of insulin resistance.

Objective: To identify risk factors for serious and specific early complications of laparoscopic gastric bypass surgery using a large national cohort of patients., Background: Bariatric procedures are among the most common surgical procedures today. There is, however, still a need to identify preoperative and intraoperative risk factors for serious complications., Methods: From the Scandinavian Obesity Surgery Registry database, we identified 26,173 patients undergoing primary laparoscopic gastric bypass operation for morbid obesity between May 1, 2007, and September 30, 2012. Follow-up on day 30 was 95.7%. Preoperative data and data from the operation were analyzed against serious postoperative complications and specific complications., Results: The overall risk of serious postoperative complications was 3.4%. Age (adjusted P = 0.028), other additional operation [odds ratio (OR) = 1.50; confidence interval (CI): 1.04-2.18], intraoperative adverse event (OR = 2.63; 1.89-3.66), and conversion to open surgery (OR = 4.12; CI: 2.47-6.89) were all risk factors for serious postoperative complications. Annual hospital volume affected the rate of serious postoperative complications. If the hospital was in a learning curve at the time of the operation, the risk for serious postoperative complications was higher (OR = 1.45; CI: 1.22-1.71). The 90-day mortality rate was 0.04%., Conclusions: Intraoperative adverse events and conversion to open surgery are the strongest risk factors for serious complications after laparoscopic gastric bypass surgery. Annual operative volume and total institutional experience are important for the outcome. Patient related factors, in particular age, also increased the risk but to a lesser extent.

Background: Several studies indicate that increasing the alimentary limb length in gastric bypass surgery produces only a minor improvement of excess BMI loss. Few studies have addressed the efficacy of increasing the length of the pancreatico-biliary limb., Methods: Here, we present a prospective randomized study of 187 consecutive laparoscopic Roux-Y gastric bypass operations operated over 2 years (2004-2005) in Iceland. The patients were operated with a gastric bypass with either a 2-m biliopancreatic (BP)-limb and a 60-cm alimentary (A)-limb (n = 93) or with a 150-cm A-limb and a 60-cm BP-limb (n = 94)., Results: Preoperative median BMI was 44.1 (38-70), median age 35.5 (17-74) years, and 85 % of the patients were female. Follow-up rate after 5 years was 85 %. Eighteen months following surgery, the weight loss was significantly higher in the BP-limb group (p < 0.001), and this difference remained 7 years after surgery. Weight regain occurred in both groups, and 7 years after surgery, excess BMI loss (EBMIL) was 78.4 % in the BP-limb group compared to 67.1 % in the A-limb group (p < 0.001). Most patients (78 %) needed supplementation adjustment (iron, vitamin D and calcium) during the study period, significantly more often in the BP-limb group compared to the A-limb group (p < 0.001). Patients in the BP-limb group had more frequent stools than patients in the A-limb group; otherwise, gastro-intestinal symptoms rating scoring were comparable. Complication rate was similar., Conclusions: Gastric bypass with a 2-m BP-limb gives better weight loss than gastric bypass with a 60-cm BP-limb and a 150-cm A-limb. Metabolic follow-up is of utmost importance, as most patients needed repeated adjustments of their supplementation.

The most frequently used and effective treatment for morbid obesity is Roux-en-Y gastric bypass surgery (RYGB), which results in rapid remission of type 2 diabetes in most cases. To what extent this is accounted for by weight loss or other factors remains elusive. To gain insight into these mechanisms, we investigated the effects of RYGB on β-cell function and β-cell mass in the pig, a species highly reminiscent of the human. RYGB was performed using linear staplers during open surgery. Sham-operated pigs were used as controls. Both groups were fed a low-calorie diet for 3 weeks after surgery. Intravenous glucose tolerance tests were performed 2 weeks after surgery. Body weight in RYGB pigs and sham-operated, pair-fed control pigs developed similarly. RYGB pigs displayed improved glycemic control, which was attributed to increases in β-cell mass, islet number, and number of extraislet β-cells. Pancreatic expression of insulin and glucagon was elevated, and cells expressing the glucagon-like peptide 1 receptor were more abundant in RYGB pigs. Our data from a pig model of RYGB emphasize the key role of improved β-cell function and β-cell mass to explain the improved glucose tolerance after RYGB as food intake and body weight remained identical.

Context: Gastric bypass surgery (GBP) results in the rapid resolution of type 2 diabetes. Most studies aiming to explain the underlying mechanisms are limited to data obtained after a postsurgical recovery period, making assessment of confounding influences from, for example, weight loss and altered nutrient intake difficult., Objective: To examine the impact of GBP on hormonal and metabolite profiles under conditions of identical nutrient intake independent of weight loss, we studied GBP patients fitted with a gastrostomy tube to enable the administration of nutrients to bypassed segments of the gut. Thus, this model allowed us to simulate partially the preoperative condition and compare this with the postoperative situation in the same patient., Design: Patients (n = 4) were first given a mixed meal test (MMT) orally and then via the gastrostomy tube, preceded by overnight and 2-hour fasting, respectively. Blood samples were assessed for hormones and metabolites., Results: The oral MMT yielded 4.6-fold increase in plasma insulin (P < .05), 2-fold in glucagon-like peptide-1 (P < .05), and 2.5-fold in glucose-dependent insulinotropic peptide (P < .05) plasma levels, compared with the gastrostomy MMT. The changes in hormone levels were accompanied by elevated branched-chain amino acid levels (1.4-2-fold, P < .05) and suppressed fatty acid levels (∼50%, P < .05)., Conclusions: These data, comparing identical nutrient delivery, demonstrate markedly higher incretin and insulin responses after oral MMT than after gastric MMT, thereby providing a potential explanation for the rapid remission of type 2 diabetes observed after GBP. The simultaneous increase in branched-chain amino acid questions its role as a marker for insulin resistance.

Background: Conversion operations after vertical banded gastroplasty (VBG) are sometimes performed because of vomiting and/or acid regurgitation. Primary operation with gastric bypass (GBP) is known to reduce gastroesophageal reflux (GERD). Previous studies have not been designed to differentiate between the effects of the altered anatomy and of the ensuing weight loss. No series has reported data on acid reflux before and after conversion from VBG to GBP., Methods: We invited eight VBG patients with current symptoms of GERD. All had intact staple lines as assessed by barium meal and gastroscopy. Acid reflux was quantified using 48-h Bravo capsule measurements. Conversion operations were performed creating an isolated 15-20-ml pouch; the previously banded part of gastric wall was excised. Gastrojejunostomy was made end to end with a 28-mm circular stapler. The study is based on five patients consenting to early postoperative endoscopy and pH measurement., Results: All patients were women with a mean age of 49.5 years and BMI of 36.3. Time since VBG was 132.1 months. Time from conversion to second measurement was 46.6 days and BMI at that time 32.7. There was no mortality and no serious morbidity. All patients improved clinically and no patient had to go back on proton pump inhibition or antacids. Total time with pH < 4.0 was reduced from 18.4% to 3.3% (p < 0.05). DeMeester score was reduced from 58.1 to 15.9 (p < 0.05)., Conclusions: The effect of converting VBG-operated patients to GBP results in a near-normalisation of acid reflux parameters and a discontinuation of proton pump inhibitor medication.

Study Question: Do serum levels of anti-Müllerian hormone (AMH) change in women of reproductive age following dietary and surgery-induced weight loss?Summary Answer: AMH levels increased after very low-calorie diet (VLCD) before surgery and decreased at 6 and 12 months after Roux-en-Y gastric bypass (RYGB), beyond expected normal age-related decline.What Is Known Already: Obesity has negative effects on fertility and IVF outcomes, and possibly also on AMH levels. AMH correlates to the number of growing follicles and is used to predict the response to IVF treatment. However, AMH might decrease after bariatric surgery.Study Design, Size, Duration: A prospective cohort study of 48 women followed first for 8 weeks preoperatively, then operated with RYGB and followed postoperatively for 1 additional year.Participants/materials, Setting, Methods: Women aged 18-35 years with a mean (SD) BMI 40.9 (3.6) kg/m2 were included at baseline (BL). After the VLCD, a RYGB was performed. Body weight and height were measured at BL and 1 year postoperatively. Hormones were analysed at BL, after VLCD on the day before surgery, and at 6 and 12 months postoperatively.Main Results and the Role Of Chance: Median AMH levels were 30.0 pmol/L at BL and rose significantly after VLCD (median: 35.0 pmol/L; P = 0.014). Median AMH at 6 and 12 months postoperatively were significantly lower (19.5 and 18.0 pmol/L, respectively; P = 0.001). Free androgen index (FAI) was significantly lower after 12 months, compared to BL (1.2 vs 3.5, P < 0.0005).Limitations Reasons For Caution: Ultrasound for PCOS diagnosis was not performed. The change in laboratory methods for AMH analysis during the study might be a limitation.Wider Implications Of the Findings: Obese young women might choose bariatric surgery also for fertility reasons, and the observed decrease in FAI is in line with improved fertility. More research is needed to evaluate the clinical effects of the decrease of AMH, and the effect of bariatric surgery prior to IVF treatment.Study Funding/competing Interest(s): Study-specific laboratory analyses were funded by the Swedish Regional Research Fund (ALF). Authors declare no competing interests.Trial Registration Number: N/A. [ABSTRACT FROM AUTHOR]

Background Anastomotic leak is one of the most serious complications following bariatric laparoscopic Roux-en- Y gastric bypass ( LRYGB), and associated with high morbidity rates and prolonged hospital stay. Timely management is of utmost importance for the clinical outcome. This study evaluated the approach to suspected leakage in a high-volume bariatric surgery unit. Methods All consecutive patients who underwent LRYGB performed by the same team of surgeons were registered prospectively in a clinical database from September 2005 to June 2012. Suspected leaks were identified based on either clinical suspicion and/or associated laboratory values, or by a complication severity grade of at least II using the Clavien-Dindo score. Results A total of 6030 patients underwent LRYGB during the study period. The leakage rate was 1·1 per cent (64 patients). Forty-five leaks (70 per cent) were treated surgically and 19 (30 per cent) conservatively. Eight (13 per cent) of 64 patients needed intensive care and the mortality rate was 3 per cent (2 of 64). Early leaks (developing in 5 days or fewer after LRYGB) were treated by suture of the defect in 20 of 22 patients and/or operative drainage in 13. Late leaks (after 5 days) were managed with operative drainage in 19 of 23 patients and insertion of a gastrostomy tube in 15. Patients who underwent surgical treatment early after the symptoms of leakage developed had a shorter hospital stay than those who had symptoms for more than 24 h before reoperation (12·5 versus 24·4 days respectively; P < 0·001). Conclusion Clinical suspicion of an anastomotic leak should prompt an aggressive surgical approach without undue delay. Early operative treatment was associated with shorter hospital stay. Delays in treatment, including patient delay, after symptom development were associated with adverse outcomes. [ABSTRACT FROM AUTHOR]