Protein deficiency after gastric bypass: The role of common limb length in revision surgery

American society for metabolic and bariatric surgery: intra-operative care pathway for minimally invasive Roux-en-Y gastric bypass

BACKGROUND

Clinical care pathways help guide and provide structure to clinicians and providers to improve healthcare delivery and quality. The Quality Improvement and Patient Safety Committee (QIPS) of the American Society for Metabolic and Bariatric Surgery (ASMBS) has previously published care pathways for the performance of laparoscopic sleeve gastrectomy (LSG) and pre-operative care of patients undergoing Roux-en-Y gastric bypass (RYGB).

OBJECTIVE

This current RYGB care pathway was created to address intraoperative care, defined as care occurring on the day of surgery from the preoperative holding area, through the operating room, and into the postanesthesia care unit (PACU).

METHODS

PubMed queries were performed from January 2001 to December 2019 and reviewed according to Level of Evidence regarding specific key questions developed by the committee.

RESULTS

Evidence-based recommendations are made for care of patients undergoing RYGB including the pre-operative holding area, intra-operative management and performance of RYGB, and concurrent procedures.

CONCLUSIONS

This document may provide guidance based on recent evidence to bariatric surgeons and providers for the intra-operative care for minimally invasive RYGB.

Effects of gastric bypass on the digestibility and postprandial metabolic fate of 15N dietary protein in rats

Roux-en-Y Gastric Bypass may be associated with an alteration of protein bioavailability in relation to intestinal remodeling. Our study aimed to test this hypothesis by Roux-en-Y Gastric Bypass. Diet-induced obese rats underwent Roux-en-Y Gastric Bypass surgery (RYGB rats) while a Sham-operated control group was used. All rats received a 15N-labeled protein meal 1 or 3 months after surgery and were euthanized 6h later. Protein digestibility, 15N recovered in organs and urea pool, fractional protein synthesis rate, and intestinal morphometry were assessed. Protein digestibility was similar in all groups (94.2±0.3%). The small intestine was hypertrophied in RYGB rats 1 month after surgery, weighing 9.1±0.2g vs. 7.0±0.3g in Sham rats (P = 0.003). Villus height and crypt depth were increased in the alimentary limb and ileum of RYGB rats. However, Roux-en-Y Gastric Bypass had no impact on the fractional synthesis rate. In the gastrointestinal tract, 15N retention only differed in the ileal mucosa and was higher in RYGB rats at 1 month (0.48±0.2% vs. 0.3±0.09%, P = 0.03). 15N recovery from the liver, muscle, and skin was lower in RYGB rats at 1 month. 15N recovery from urinary and plasma urea was higher in RYGB rats at both times, resulting in increased total deamination (13.2±0.9% vs. 10.1±0.5%, P<0.01). This study showed that Roux-en-Y Gastric Bypass did not affect protein digestibility. Dietary nitrogen sequestration was transitorily and moderately diminished in several organs. This was associated with a sustained elevation of postprandial deamination after Roux-en-Y Gastric Bypass, whose mechanisms merit further studies.

Protein malnutrition after Roux-en-Y gastric bypass: a challenging case and scoping review of the literature

Although protein malnutrition (PM) is often reported after highly malabsorptive procedures, its exact incidence and mechanisms after Roux-en-Y gastric bypass (RYGB) are poorly understood. The aim of this study was to present a challenging clinical case of PM after RYGB and conduct a scoping review of the literature. Among the 18 studies with 3015 RYGB patients included in the review, the median incidence of PM was 1.7% (range, 0%-8.9%), and it was diagnosed 12 to 120 months after RYGB. The most common cause is insufficient oral intake of protein; however, in cases of persistent hypoalbuminemia, a thorough diagnostic workup needs to be performed. Risk factors for PM after RYGB include specific triggering events such as intractable vomiting and dysphagia, and a total alimentary limb length less than 250 to 300 cm.

Outcomes of laparoscopic revisional conversion of sleeve gastrectomy to Roux-en-Y gastric bypass: Diff erent strategies for obese and non-obese Asian patients

BACKGROUND

Sleeve gastrectomy (SG) is the most performed bariatric procedure now. Some patients would necessitate a revision to Roux-en-Y gastric bypass (RYGB) as a salvage procedure for intractable gastroesophageal reflux disease (GERD). However, outcome of the revision in Asians with co-existed obesity and those non-obese is not clear.

METHODS

We retrospectively reviewed the data of patients who underwent revisional laparoscopic RYGB after SG between 2007 and 2019 for intractable GERD with data of one year follow-up. Pre-operative clinical data, perioperative outcomes, GERD symptoms, weight loss and medication details were analyzed. Patients were classified into those with body mass index (BMI) ≥ 25 and < 25 kg/m².

RESULTS

Fifty-five patients (44 women, 11 men; mean age 42.5 years) were included. Mean interval from the initial SG to revision surgery was 51.2 months (range, 5-132). Mean body mass index before SG was 34.6 kg/m², whereas that before revision surgery was 27.6 kg/m². All the patients required continue proton pump inhibitor (PPI) to control the GERD symptoms before surgery. Among them, 36 (65.4%) patients in the obese group received long BP limb (>100 cm) RYGB for associated obesity but the common channel was assured to ≥ 400 cm or 70% of small bowel length, the other 19 (34.6%) patients in the non-obese group received standard BP limb (<100 cm) RYGB. There was no difference in basic characters between the two groups before revision surgery except a higher mean BMI (30.0 vs. 22.2 kg/m², p < 0.001), blood pressure and triglyceride in obese group. One year after revision surgery, all the patients had improved GERD symptoms but only 33 (60%) can completely wave PPI, without difference between the 2 groups. Obese group with a long BP limb RYGB had a significant higher % total weight loss (TWL) than non-obese group (%TWL 9.1% vs. -3.1%, p = 0.005).

CONCLUSION

Laparoscopic revision to RYGB is a safe and effective treatment for patients with intractable GERD after SG but some patients may still have residual GERD symptoms. Using a modified RYGB technique in revision surgery may help in weight reduction for obese Asian patients.

Optimal common limb length in Roux‐en‐Y gastric bypass surgery: is it important for an ideal outcome? – a systematic review

BACKGROUND

In Roux-en-Y gastric bypass (RYGB) surgery the common limb length (CLL) is thought to significantly impact on nutritional and metabolic outcomes. However, there has been little focus on establishing routine standardized CLL measurements and its subsequent effect on weight loss and nutritional status. This review aimed to determine the effect of variations of CLL in RYGB surgery on post-operative outcomes, particularly nutritional status, while considering the need for routine CLL measurements in addition to measuring biliopancreatic limb and alimentary limb lengths.

METHODS

A systematic review was performed in accordance with the PRISMA guidelines. All English language articles addressing CLL and impact on weight loss, nutritional and metabolic outcomes were retrieved and reviewed.

RESULTS

Thirteen relevant studies were identified with CLLs varying from 76 to >600 cm. No significant difference in total body weight loss or excess weight loss was observed. Significant metabolic improvements occurred with shorter CLLs. Nutritional deficiencies were more severe when the CLL was <400 cm.

CONCLUSION

The data from this systematic review suggests that reasonable weight loss and positive impacts on metabolic outcomes can be achieved with CLLs of >400 cm.

Experience of the First 100 OAGB in China: OAGB In Situ Technique

Background

One anastomosis gastric bypass (OAGB) is gradually accepted worldwide but still new in China.

Materials and Methods

Retrospective review of the patients who received OAGB in a new bariatric/metabolic surgical center in China and compared the data with a center of excellence in Taiwan. All in-patient and outpatient follow-up data were analyzed. The main outcome measures were (1) operation risk (2) weight loss (3) diabetes remission.

Results

Between August 2019 and October 2021, 100 consecutive patients who received OAGB in situ in China and 225 patients who received OAGB with the same technique were recruited from Taiwan. Taiwan patients were older (39.2 ± 10.6 vs. 33.3 ± 8.8 years old, p < 0.001), and to have more diabetes (32.4% vs. 20.0%, p = 0.022) comparing to the patients of China. Operation time was significantly longer for Taiwan patients (172.4 ± 36.9 vs. 128.5 ± 29.8, p < 0.001). Taiwan patients lost more blood during the operation (35.5 ± 25.2 vs. 22.4 ± 15.6, p < 0.001) but patients in China need more time to postoperative flatus passage (1.3 ± 0.5 vs. 2.0 ± 0.5, p < 0.001). There was no major surgical complication in this study, minor complication rates were similar low for both groups (1.0% vs. 1.8%, p = 0.891). At 1 year after surgery, %TWL and %EWL of both centers were similar (33.9 ± 7.43% vs. 32.6 ± 11.2%, p = 0.91; 81.9 vs. 19.8 vs. 85.4 ± 13.2, p = 0.798). T2DM remission (HbA1c < 6.5%) was 100% for patients of China and 95.9% for patients of Taiwan (p = 0.836).

Conclusions

OAGB in situ is a safe and effective bariatric/metabolic surgery. With proper training and proctorship, these results are reproduceable in a new bariatric/metabolic surgical center in China.

Graphical abstract

Excessive weight loss after bariatric surgery: a prediction model retrospective cohort study

Bariatric surgery has been recognized as the most effective long-term treatment for morbid obesity. Despite the considerable positive results, adverse consequence can develop. Excessive Weight Loss (EXWL), a rare consequence of bariatric surgery, can lead to a broad adverse consequence. The aim of this study was determining of prevalence and the predicting model of EXWL in patient underwent bariatric surgery until 24 months after surgery. Data have been extracted from the National Obesity Surgery Database in obesity clinic of Iran University of Medical Sciences. The subjects of this retrospective cohort study were morbid obese individuals who underwent three various types of bariatric surgery [One Anastomosis Gastric Bypass (OAGB), Roux-en-Y Gastric Bypass (RYGB), or Sleeve Gastrectomy (SG)] in period of 24 months ago. EXWL has been defined as reaching to less than or equal to BMI 18.5 at any time until 24 months after surgery. SPSS was used in data analysis. Among 4214 subjects of this study, most excess weight loss after surgery has taken place in 18 months after surgery. 11.4% (n = 495) of patients experienced EXWL with highest percentage among OAGB patients (15.1%) at time of 24 months after surgery. The females (20.4% vs.9.9%) and younger persons (35.45 ± 10.25 vs. 39.06 ± 10.76) were more susceptible to EXWL. Patients with EXWL had significantly lower BMI (body mass index) (41.11 ± 4.51 vs. 46.73 ± 6.26) (Kg/m²), and were less probable to had emotional eating. Visceral fat level, fat percentage, and BMI were the best predictor of EXWL (P value for all < 0.05). So that per level increase in visceral fat, decreases the probability of EXWL as 47% and 61% in SG and OAGB. Moreover, each unit lower BMI leads to 25% higher susceptibility to experience EXWL. Surgery should be adjusted in younger females with a lower BMI and healthy metabolic status who are more prone to EXWL. In such a way that minimize weight loss speed/value. It may be possible by selection of other surgery procedures, rather than OAGB, tighter follow-ups, and consultations of patients after surgery is emphasized for more EXWL vulnerable patients.

Nutritional Complications After Laparoscopic Roux-en-Y Gastric Bypass and One-Anastomosis Gastric Bypass: A Comparative Systematic Review and Meta-Analysis

A systematic review and meta-analysis were carried out involving studies that compared the nutritional complications of Roux-en-Y gastric bypass (RYGB) and one-anastomosis gastric bypass (OAGB); these included the incidence of malnutrition as well as deficiencies of other nutritional elements, such as total protein, albumin, calcium and iron. A comprehensive search strategy was implemented in PubMed, Embase, and the Cochrane Library. Effect sizes included the pooled odds ratios (ORs) and 95% confidence intervals (95% CIs), as well as mean differences (MDs) and 95% CIs of the percentage total weight loss (%TWL) and excess weight loss percentage (%EWL). Thirteen studies were included (12,964 patients, 66.27% females, 53.82% underwent OAGB). At the longest follow-up period (≥3 years), OAGB was associated with significantly higher %TWL (MD=5.41%, 95%CI, 1.52 to 9.29) and %EWL (MD=13.81%, 95%CI, 9.60 to 18.02) compared to RYGB. However, OAGB procedures were associated with malnutrition (OR=3.00, 95%CI, 1.68 to 5.36, p<0.0001), hypoalbuminemia (OR=2.38, 95%CI, 1.65 to 3.43, p<0.0001), hypoproteinemia (OR=1.85, 95%CI, 1.09 to 3.14, p=0.022), anemia (OR=1.38, 95%CI, 1.08 to 1.77, p=0.011), and hypocalcemia (OR=1.78, 95%CI, 1.01 to 3.12, p=0.046). On subgroup analyses, the proportions of anemia and hypoalbuminemia remained significantly higher at longer follow-up periods and in studies published in Asia. Despite the favorable weight loss profile, the unfavorable nutritional consequences of OAGB merits further investigations to explore the malabsorptive element, ethnic variation, and the role of biliopancreatic limb length.

Factors Associated with Nutritional Deficiency Biomarkers in Candidates for Bariatric Surgery: A Cross-Sectional Study in a Peruvian High-Resolution Clinic

Previous studies have described multiple nutritional deficiencies after bariatric surgery (BS). However, few studies have evaluated these deficiencies prior to BS, specifically in Latin America. This study aimed to determine the factors associated with nutritional deficiency biomarkers in candidates for BS in Peru. We included adults of both sexes, aged 18 to 59 years, admitted to a Peruvian clinic with a body mass index (BMI) ≥30 kg/m2; they were candidates for BS from 2017 to 2020. We considered the serum levels of hemoglobin and albumin (in tertiles) as the nutritional deficiency biomarkers. In order to assess the associated factors, we calculated crude (cPR) and adjusted prevalence ratios (aPR) with their respective 95% confidence intervals (95%CI). We analyzed 255 patients: 63.1% were males, with a mean age of 37.1 ± 10.3 years and mean hemoglobin and albumin values of 14.0 ± 1.5 g/dL and 4.6 ± 0.4 g/dL, respectively. We found that males (aPR = 1.86; 95%CI: 1.26–2.73; p = 0.002), participants between 30 and 49 (aPR = 2.02; 95%CI: 1.24–3.28; p = 0.004) or 50 years or more (aPR = 2.42; 95%CI: 1.35–4.35; p = 0.003), participants with a BMI ≥40 kg/m2 (aPR = 1.68; 95%CI: 1.09–2.60; p = 0.018), participants with impaired high-density lipoprotein levels (aPR = 1.43; 95%CI: 1.01–2.05; p = 0.049) and individuals in the high tertile of C-reactive protein (aPR = 6.94; 95%CI: 3.37–14.32; p < 0.003) had a higher probability of being in the lower tertile of albumin. In addition, we found that the male sex (aPR = 6.94; 95%CI: 3.37–14.32; p < 0.001) and elevated cholesterol levels (aPR = 0.71; 95%CI: 0.52–0.97; p = 0.034) were associated with the lowest hemoglobin tertile. In our setting, nutritional deficiency biomarkers were associated with sociodemographic, anthropometric and laboratory markers. The pre-bariatric surgery correction of nutritional deficiencies is essential, and can prevent major complications after surgery.

Long-Term Efficacy of Bariatric Surgery for the Treatment of Super-Obesity: Comparison of SG, RYGB, and OAGB

BACKGROUND

The most appropriate procedure for the treatment of super obesity (BMI > 50 kg/m²) is unknown. We aimed to evaluate the safety, long-term (> 5 years) weight loss, and adverse events between three commonly performed procedures, sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and one anastomosis gastric bypass (OAGB) in super-obese patients.

METHODS

Between January 2002 and December 2015, 498 successive patients with super morbid obesity (BMI > 50), who underwent SG or RYGB or OAGB, were recruited. Surgical outcome, weight loss, resolution of co-morbidities, and late complications were followed and compared between the 3 groups. All data derived from a prospective bariatric database and a retrospective analysis was conducted.

RESULTS

The average patient age was 32.1 ± 10.4 years, with a mean body mass index (BMI) of 56.0 ± 6.7 kg/m². Of them, 190 (38.9%) underwent SG, 62 (12.4%) RYGB, and 246 (49.4%) OAGB. There was no difference in basic characters between the 3 groups except SG had fewer diabetic patients. RYGB group had higher intraoperative blood loss, longer operating time, and hospital stay than the other 2 groups. RYGB had a higher 30-days post-operative major complication rate (4.8%) than SG (0.5%) and OAGB (0.8%). The follow-up rate at 1 and 5 years was 89.4% and 52.0%. At post-operative 5 years, OAGB had a higher total weight loss (40.8%) than SG (35.1%), but not RYGB (37.2%). SG had a lower remission rate in dyslipidemia comparing to OAGB and RYGB, but T2DM remission rate was no different between the groups. The overall revision rate is 5.4% (27/498) of the whole group, and SG had a lower revision rate (2.6%) than RYGB (8.1%) and OAGB (6.9%).

CONCLUSION

SG is an effective and durable primary bariatric procedure for the treatment of super obesity and metabolic disorders. OAGB had a similar operation risk to SG but resulted in a better weight loss than SG.

Efficacy and Drawbacks of Single-Anastomosis Duodeno-Ileal Bypass After Sleeve Gastrectomy in a Tertiary Referral Bariatric Center

Background

The need for revisional procedures after sleeve gastrectomy (SG) for insufficient weight loss or weight regain, gastroesophageal reflux, or other complications is reported to be 18–36% in studies with 10-year follow-up. Single-anastomosis duodeno-ileal bypass (SADI) may be performed as a revisional procedure after SG. This study aims to evaluate the short- and mid-term outcomes of SADI after SG in a referral center for bariatric surgery.

Materials and Methods

Data of patients who underwent SADI between March 2015 and March 2020 were collected prospectively and analyzed retrospectively. Follow-up comprised clinical and biochemical assessment at 1, 3, 6, 12, 18, and 24 months postoperatively, and once a year thereafter.

Results

Overall, 106 patients underwent SADI after a previous SG. The timeframe between SG and SADI was 50 ± 31.3 months. Postoperative mortality was observed in two cases (1.8%) and morbidity in 15.1% of patients. At 24 months, %total weight loss was 37.6 ± 12.3 and %excess weight loss 76.9 ± 25.2 (64 patients). Three patients were treated for malnutrition during follow-up, two with medical treatment and one with SADI reversal.

Conclusion

SADI after SG provides effective weight loss results in the short-term, even if in the present series the postoperative complication rate was non-negligible. Further trials are needed to establish the more advantageous revisional bariatric procedure after failed SG.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11695-021-05323-y.

Twenty years' experience of laparoscopic 1-anastomosis gastric bypass: surgical risk and long-term results

BACKGROUND

Laparoscopic 1- (single-) anastomosis gastric bypass (OAGB) was developed as a simplified technique of Roux-en-Y gastric bypass (RYGB), but super long-term data are lacking.

OBJECTIVES

To evaluate the risks and long-term results of OAGB over a period of 20 years.

SETTING

Tertiary teaching hospital.

METHODS

A total of 2223 patients underwent OAGB from 2001 to 2020; the mean age was 35.3 ± 11.4 years (range, 14-71 yr), 70.2% were female, and the mean body mass index was 40.2 ± 11.9 kg/m². All data were kept in a prospective bariatric database. Patients were divided into 4 groups, based on the 5-year period in which their surgery was performed, and a retrospective analysis was conducted.

RESULTS

The means for operating time, intraoperative blood loss, and length of hospital stay after OAGB were 131.9 ± 40.1 minutes, 38.5 ± 30.7 mL, and 4.5 ± 4.0 days, respectively. There were 27 patients (1.2%) with 30-day postoperative major complications overall, but the group rate decreased to .4% in the last 5-year period. At postoperative years 5, 10, and 15, the percentages of total weight loss were 31.9%, 29.6%, and 29.5%, respectively, and the percentages of excess weight loss were 77.2%, 68.4%, and 65.5%, respectively. Among 739 patients (33.2%) with type 2 diabetes (T2D), the rates of complete remission (glycated hemoglobin < 60%) at 5, 10, and 15 years were 67.3%, 73.8%, and 66.7%, respectively. The weight loss and antimetabolic effects were similar in each 5-year period, but a significant malnutrition effect was observed. A total of 113 (5.1%) patients needed revision surgery at follow-up, due to malnutrition (n = 51), weight regain (n = 24), acid or bile reflux (n = 22), marginal ulcer (n = 8), ileus (n = 3), and other causes (n = 5). At 15 years, the overall revision rate was 11.9% (27/226), and 80% of the patients were very satisfied with their procedures.

CONCLUSION

Our results showed that OAGB is a safe and durable primary bariatric procedure, with sustained weight loss and a high resolution of T2D up to 20 years post surgery in Taiwan, although malnutrition is a major side effect.

One Anastomosis Gastric Bypass for the Treatment of Type 2 Diabetes: Long-Term Results and Recurrence

BACKGROUND

Bariatric/metabolic surgery has been incorporated into the therapeutic treatment of type 2 diabetes mellitus (T2DM). Among many bariatric/metabolic procedures, one anastomosis gastric bypass (OAGB) is one of the most effective procedures but long-term data about T2DM recurrence after OAGB are lacking.

METHODS

Outcomes of 134 patients who had undergone OAGB for the treatment of T2DM with long-term (5 years) follow-up were assessed in a retrospective cohort study. The remission of T2DM after OAGB surgery was evaluated in different groups using a scoring system composed of the age, BMI, C-peptide level, duration of T2DM (ABCD score), and percent of total weight loss (%TWL).

RESULTS

The %TWL and percent of excess weight loss (%EWL) of the OAGB patients at 5 years after surgery were 29.2 (10.6) and 72.1(27.5), respectively. The mean BMI decreased from 39.5(7.9) to 27.6(5.3) kg/m² and mean glycated hemoglobin A1C (HbA1c) decreased from 8.9 to 5.9% in OAGB patients at 5 years after OAGB. The complete T2DM remission rate of OAGB was 76.1% at 1 year and 64.2% at 5 years after surgery. Forty-one (57.8%) out of 71 patients who completed a 10-year follow-up remained in complete T2DM remission. The T2DM recurrence rate of OAGB patients was 15.7% at 5 years after surgery.

CONCLUSIONS

OAGB is highly effective in inducing T2DM remission but a significant number of patients will still have T2DM recurrence. To select patient with an ABCD score > 5 and maintaining a weight loss greater than 30% is important for durable T2DM remission after OAGB.

Variation in Small Bowel Length and Its Influence on the Outcomes of Sleeve Gastrectomy

PURPOSE

Small bowel length is drawing attention in the development of gastrointestinal bariatric/metabolic surgery, but the importance of the length of the small bowel in bariatric/metabolic is not clear. The present study was conducted to investigate variations in small bowel length and their clinical significance in patients undergoing laparoscopic sleeve gastrectomy (LSG).

MATERIALS AND METHODS

Small bowel length was measured in 620 patients diagnosed with obesity who underwent LSG between March 2014 and August 2018. Prospectively obtained demographic and clinical data were investigated, focusing on the association between small bowel length and weight loss.

RESULTS

Small bowel length varied widely among patients (mean 739.8 + 115.7 cm, range 380-1050 cm). Linear regression analysis revealed a significant association between small bowel length and body height, body weight, waist circumference, and serum levels of low-density lipoprotein cholesterol, hemoglobin, C-peptide, glycated hemoglobin (A1C), and gamma-glutamyl transferase (r-GT). Multivariate analysis confirmed that body height and serum A1C% levels independently predicted small bowel length in bariatric patients, strongly with body height (p < 0.001) but weakly with A1C%(p = 0.021). One-year follow-up rate was 75.3% (467/620), and small bowel length did not influence weight loss or the reduction of obesity related cardiovascular risk factors after LSG.

CONCLUSION

In this study, small bowel length varied widely among bariatric patients and was strongly associated with body height and weakly with serum A1C levels. Small bowel length has no significant role in weight loss or the resolution of cardiovascular risk factors after LSG.

Randomized Controlled Trial of One Anastomosis Gastric Bypass Versus Roux-En-Y Gastric Bypass for Obesity: Comparison of the YOMEGA and Taiwan Studies

BACKGROUND

The YOMEGA study (Y-study) was a randomized trial comparing one anastomosis gastric bypass (OAGB) and Roux-en-Y gastric bypass (RYGB). Here, we aim to compare the Y-study and our pioneer trial from Taiwan (T-study).

METHODS

Data from the Y-study and the T-study were collected and compared.

RESULTS

The Y-study recruited 234 patients with a mean body mass index (BMI) of 43.9 and age of 43.5 years. The T-study recruited 80 patients with a similar mean BMI of 44.3 and mean age of 31.4 years. The studies had similar findings including (1) OAGB is easier and possibly safer procedure than RYGB. Both studies showed that OAGB had a shorter operation time than RYGB, but a lower surgical complication rate was only demonstrated in T-study. (2) Both procedures have similar weight loss but OAGB features better glycemic control than RYGB. Weight loss at 2 years after surgery was similar between two procedures, but OAGB reduced HbA1c to a greater degree than RYGB at 2 years in Y-study (- 2.3% vs. - 1.3%; p = 0.025). The resolution of the metabolic syndrome was 100% for both groups in the T-study. (3) OAGB carried a higher risk of malnutrition. OAGB had more malabsorptive problems with a lower hemoglobin level than RYGB at 2 years after surgery. Adverse malnutrition events occurred in nine (7.8%) OAGB patients in the Y-study. Four (3.4%) patients of OAGB received revision surgery in Y-study but none in T-study. (4) Bile reflux was noted in OAGB patients but did not influence quality of life or revision rate. Y-study found that bile in the gastric pouch was present in 16% of patients in the OAGB group versus none in the RYGB, but no inter-group difference in quality of life was detected. There was a trend for RYGB patients to experience more abdominal pain than OAGB.

CONCLUSIONS

Both studies showed that OAGB is a technically easier procedure and features better glycemic control than RYGB, but has a mal-absorptive effect. However, the bile reflux and abdominal pain controversies persisted.