Journal Watch 2/4/2025

Welcome to our weekly round-up of the latest bariatric and obesity-related papers published in the medical literature. As ever, we have looked far and wide to give you an overview of papers including By-Band-Sleeve outcomes, normal variation in total alimentary limb length does not significantly impact weight loss, greater weight loss at ten years with RYGB vs LSG, reintervention prevalence of BMS patients with eating disorders, magnetic duodeno-ileal anastomosis is safe and feasible, tirzepatide SUMMIT outcomes, and more (please note, log-in maybe required to access the full paper).

Roux-en-Y gastric bypass, adjustable gastric banding, or sleeve gastrectomy for severe obesity (By-Band-Sleeve): a multicentre, open label, three-group, randomised controlled trial

Roux-en-Y gastric bypass and sleeve gastrectomy are more effective than adjustable gastric banding, according to the latest outcomes from the By-Band-Sleeve trial.

The outcomes, published in The Lancet Diabetes & Endocrinology by By-Band-Sleeve Collaborative Group, also found sleeve gastrectomy had inferior weight loss compared with Roux-en-Y gastric bypass, and sleeve gastrectomy was less clinically effective for quality-of-life compared with Roux-en-Y gastric bypass.

In addition, costs per participant over the three years, were highest for Roux-en-Y gastric bypass and lowest for adjustable gastric banding. Combining the costs and QALYs, Roux-en-Y gastric bypass was the most cost-effective option at the cost-utility thresholds applied by NICE, with low probabilities that sleeve gastrectomy (<0.30) or adjustable gastric banding (<0.02) are the most cost-effective option.

“Based on this evidence, it is recommended that patients electing to have metabolic and bariatric surgery are advised to have Roux-en-Y gastric bypass. Where contraindicated or unfeasible, sleeve gastrectomy should be offered,” the authors concluded. “This evidence does not support adjustable gastric band as standard treatment for severe obesity.”

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Total Alimentary Limb Length Is Not Associated with Weight Loss Following Proximal Roux-en-Y Gastric Bypass

With a fixed biliopancreatic limb length (BPL, 50 cm), normal variation in total alimentary limb length (TALL) does not significantly contribute to weight loss variability following RYGB, a study led by researchers from Vanderbilt University Medical Center, Nashville, TN, has found.

Writing in Obesity Surgery, sought to test the hypothesis that TALL is associated with postoperative weight loss following primary laparoscopic RYGB. A total of 329 patients were recruited, of these patients, 208 had successful measurement of the small bowel length (SBL) and underwent RYGB with a fixed biliopancreatic limb length (BPL, 50 cm). Common channel length (CCL) was allowed to vary normally to test the association between TALL and postoperative weight loss.

Follow-up rates were 77% at 6 months and 41% at 24 months. Average SBL was 592 cm (min = 390 cm, max = 910 cm), with a standard deviation of 107 cm that led to significant variation in CCL (shortest 190 cm, longest 730 cm). Regression was used to model weight loss and body mass index, as well as percent change from baseline, for each patient given the measured TALL and CCL.

Despite significant variation in TALL, there were no clinically significant effects of TALL or CCL on weight loss up to 24 months. Future studies are needed to better understand the importance of intestinal limb lengths in primary and revisional RYGB surgery, they concluded.

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Greater durability of weight loss at ten years with gastric bypass compared to sleeve gastrectomy

Gastric bypass (GB) was able to produce greater %TWL and less weight regain than LSG at five and ten years post-operatively however, there was no difference in long-term T2DM remission rates between the two surgeries, researchers from Singapore report.

Writing in the International Journal of Obesity, 253 patients underwent LSG (60.9%) and GB (39.1%). The mean age was 41.4 ± 10.6 y, 39.1% were male, and the mean body mass index was 42.1 ± 9.3 kg/m2 with no significant difference between groups. The GB group had a greater proportion of subjects with DM (83.8% vs 19.5%, p<0.001). At two years, %TWL was comparable (GB: 22.3 ± 9.6%, SG: 22.6 ± 10.5%, p=0.824).

However, those who underwent GB had significantly higher %TWL at five years (GB: 21.5 ± 8.9%, SG 18.0 ± 11.3%, p=0.029) and ten years (GB: 21.0 ± 9.0%, SG: 15.4 ± 12.1%, p=0.001). The rate of significant weight regain was higher amongst the SG group at both five years (SG: 14.7%, GB: 3.8%, p = 0.018) and 10 y (SG: 27.9%, GB: 13.7%, p=0.037) post-operatively. On multiple linear regression, GB remained significantly associated with greater %TWL at ten years compared to SG (p=0.013), after adjusting for age, sex, pre-operative BMI, pre-operative glycaemic status, and surgery year. There was no difference in DM remission rates at ten years (SG: 26.7%, GB: 19.1%, p=0.385).

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Cross-sectional analysis of eating disorder risk and risk correlates in candidates for bariatric surgery from the BariPredict cohort

Researchers from Kuwait have found that high preintervention prevalence of patients with eating disorders (ED), with a risk profile corresponding to BMI of 35-39.9 Kg/m2 in younger adults with concurrent depression, should be prioritised for psychological assessment and support to potentially improve outcomes of bariatric surgery.

Writing in Scientific Reports, they conducted a cross-sectional analysis of 275 patients from the BariPredict cohort, a study assessing predictors of long-term surgery outcomes. Psychological assessments were conducted using SCOFF, KUAS, and BDI tools and the data were analysed for prevalence of high ED risk and for associations of clinical, biological and demographic factors.

They reported that class II obesity (p<0.05), younger age (p<0.01) and higher depression (p<0.01) were associated with ED risk in a logistic regression adjusted for age, obesity class, diabetes, HbA1c, depression and anxiety scores.

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Immediately-Patent Magnetic Duodeno-Ileal Anastomosis (IMPA-DI): The First-in-Human Study

An international team of researchers has concluded that outcomes from the first-in-human study demonstrates the feasibility, safety, and efficiency of the IMPA-DI approach using Flexagon SFMs and the OTOLoc system.

Writing in Obesity Surgery, they stated that the OTOLoc system, combined with Flexagon self-forming magnets (SFMs), enables immediate patency during healing. This paper reported the first-in-human experience of immediately patent magnetic duodeno-ileal anastomosis (IMPA-DI) using these novel devices during single anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S).

Seven procedures were successfully completed, with a median overall duration of 58 min and magnet placement duration of 12 min. Three intraoperative AEs (serosal and liver injuries, staple line bleeding) were unrelated to IMPA and resolved without complications. All patients resumed liquid diets within two days, and no anastomosis-related AEs were observed within 30 days. All devices were naturally expelled without complications.

The immediate patency and straightforward deployment highlight the potential for broader application in challenging anastomotic sites. While limited by the small sample size and single-centre design, the results underscore the promise of magnetic compression anastomoses. Further studies are warranted to validate these findings and explore long-term outcomes, they concluded.

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Interplay of Chronic Kidney Disease and the Effects of Tirzepatide in Patients With Heart Failure, Preserved Ejection Fraction, and Obesity: The SUMMIT Trial

US researchers have reported long-term tirzepatide improves renal function (both by cystatin C and creatinine), but the measurement of estimated glomerular filtration rate (eGFR) in patients with obesity receiving incretin-based drugs is likely to be skewed by the effects of fat and muscle mass (and by changes in body composition) on the synthesis of both cystatin C and creatinine.

Published in the Journal of the American College of Cardiology, their analysis of data from the SUMMIT trial had dual objectives: 1) to evaluate the influence of CKD on the clinical responses to tirzepatide in patients with obesity-related HFpEF; and 2) to investigate the complexity of tirzepatide-related changes in renal function. For both objectives, they focused on discrepancies between creatinine-based and cystatin C–based estimates of eGFR.

The SUMMIT trial randomly assigned 731 patients with HFpEF and a body mass index ≥30 kg/m2, who were enriched for participants with CKD. Patients received either placebo or tirzepatide for a median of 104 weeks and were followed for cardiovascular death or worsening heart failure events and for changes in the Kansas City Cardiomyopathy Questionnaire Clinical Summary Score (KCCQ-CSS) after 52 weeks.

Patients with CKD (based on creatinine or cystatin C) had greater severity of heart failure, as reflected by: 1) worse functional class, KCCQ-CSS scores, and 6-minute walk distance; 2) higher levels of NT-proBNP and cardiac troponin T; and 3) a 2-fold increase in the risk of worsening heart failure events. CKD did not influence the effect of tirzepatide to reduce the relative risk of major adverse heart failure events and to improve KCCQ-CSS, quality of life, and functional capacity, but the absolute risk reduction in the primary events was numerically greater in patients with CKD.

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