Journal watch 15/10/2025

Welcome to our regular 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 dumping syndrome post-OAGB, the economic impact of bariatric surgery, boredom and stress as predictors of loss of control eating after surgery, increased physical activity associated with greater fat mass loss following MBS, MBSAQIP risk/benefit calculator predicting weight loss in adolescents and a scoping review of OAGB, and more (please note, log-in maybe required to access the full paper).

Incidence and Risk Factors of Dumping Syndrome After One-Anastomosis Gastric Bypass (OAGB)

Researchers form Iran University of Medical Sciences, Tehran, Iran, have reported dumping syndrome (DS) affects approximately one in five patients one year following OAGB, with early DS being more prevalent than late, although increasing age and the presence of dyslipidaemia (DLP) appear to reduce the risk.

Writing in Obesity Surgery, they assess the incidence of DS and identify its potential risk factors among patients who underwent OAGB at a tertiary bariatric centre in 266 patients.  DS was assessed 12 months postoperatively using Sigstad’s scoring system to assess the incidence of DS and Art’s questionnaire to differentiate between early and late DS.

They found the prevalence of DS was 20.7% at one-year post-OAGB. Among those affected, 53% had early DS, 33% late DS and 12.5% both types. Mean BMI decreased from 45.8 ± 5.9 to 29.9 ± 4.1 kg/m2, with a total weight loss percentage of 34.4 ± 7.2%. Age (p=0.032) and dyslipidaemia (DLP) (p=0.050) were significant negative predictors of DS following OAGB, indicating a lower incidence with increasing age and in patients with DLP. There was no significant association was found between DS and sex, BMI, type 2 diabetes mellitus, hypertension or cholecystectomy. Additionally, DS presence was not significantly correlated with weight loss outcomes.

Given its impact on patient diet modification, the syndrome does not appear to enhance postoperative weight loss, the researchers added.

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Evaluating the Economic Impact of Bariatric Surgery: A Multi-year Comparative Analysis

Investigators at the University of Wisconsin, Madison, WI, have concluded that bariatric surgery patients had higher post-operative costs through four years after surgery compared to non-operative controls, primarily due to higher costs within the first year after surgery and increased outpatient costs.

Reporting in the American Journal of Surgery, patients who underwent bariatric surgery in 2018-2019 were matched 1:5 with controls who met criteria for bariatric surgery but were medically managed. Post-operative costs were compared by year after surgery and healthcare setting.

Bariatric surgery patients (n=37) had higher mean total costs years in years one to four of $26,805 (SD $47,039) vs. $14,547 ($30,170) for non-operative controls (n=185) (p<0.001]. The largest differences occurred in the outpatient setting ($16,935 ($19,807) vs. $8,972 ($14,690); p<0.0001) and during the first year after surgery ($12,616($36,422) vs. $3,355($9,367); p<0.0001).

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Boredom and Stress as Momentary Predictors of Loss of Control Eating after Metabolic and Bariatric Surgery: A Longitudinal Investigation

US researchers have reported that boredom and stress predict more severe Loss of control eating (LOCE), particularly two to three years post- metabolic bariatric surgery (MBS), highlighting this period as an opportunity for intervention.

Writing in SOARD, the authors said this is the first to investigate boredom and stress as predictors of LOCE following MBS. Using ecological momentary assessment (EMA) to evaluate boredom and stress as predictors of LOCE over three years following MBS, this study included 150 patients.

They found that stress and boredom were associated with LOCE when controlling for year since surgery. Momentary boredom predicted more severe LOCE, but only at two years post-MBS, whereas momentary stress predicted more severe LOCE at two- and three-years post-MBS, with no change between these years. Participants with higher boredom reported more severe LOCE during the EMA protocol at two- and three-years post-MBS, with the strongest association three-years post-MBS. Participants with higher stress reported more severe LOCE during the EMA protocol each year following MBS, with the strongest association at two-years post-MBS.

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Association of increased physical activity with greater fat mass loss following metabolic bariatric surgery: A longitudinal observational study

Increased physical activity after metabolic bariatric surgery (MBS) was associated with a greater reduction in weight and body fat, according to researchers from Seoul National University Bundang Hospital, Seongnam-si, Republic of Korea.

Writing in Scientific Reports, they investigated the association between increased physical activity and the changes in weight and body composition of 78 Korean subjects with obesity after MBS. Physical activity-related energy expenditure (MET-min/week) was calculated by multiplying the frequency, intensity and duration of activities. Subjects were classified into two groups based on changes in physical activity levels before and after surgery: the MET-non-increased group and the MET-increased group.

The MET-increased group had a significantly greater reduction in weight, BMI and fat mass (FM) after MBS compared to the MET-non-increased group (weight, -32.2 ± 13.0 kg vs. -25.6 ± 9.3 kg, p=0.015; BMI, -11.7 ± 4.5 kg/m2 vs. -9.1 ± 3.0 kg/m2, p=0.005; FM, -27.0 ± 11.2 kg vs. -19.4 ± 7.5 kg, p=0.002). However, no significant difference was observed in the change in muscle mass between the two groups.

A greater increase in of physical activity and exercise level was associated with a greater reduction in weight (p=0.003) and fat mass (p=0.003) after MBS when age, sex, BMI, HbA1c and baseline metabolic parameters were adjusted. The researchers added that emphasising increasing physical activity is a key component for maximising the benefits of MBS.

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Does the MBSAQIP Bariatric Surgical Risk/Benefit Calculator Accurately Predict Weight Loss in Adolescents?

Investigators from Massachusetts General Hospital, Boston and Stanford Medicine, Stanford, have reported the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) calculator predictions show weak to moderate correlation with actual weight loss at one year and should be used with caution when counselling paediatric patients considering metabolic bariatric surgery (MBS).

Published in Obesity Surgery, they researchers evaluated the accuracy of this calculator for adolescent MBS patients and explores patient factors which may be associated with prediction inaccuracy. In total, 91 patients aged over 18 and 176 adolescent patients were included in the analyses. The correlation coefficients for predicted and actual weight loss were 0.48 for patients age < 18 and 0.38 for patients 18–21. On average, the proportion of predicted weight loss actually attained at one year was 0.73. There were no statistically significant associations between calculator inaccuracy and patient age, sex, preoperative body mass index, or area deprivation index (all p>0.05).

The study authors said the findings underscore the importance of building multi-institutional collaborations and databases specific to the paediatric MBS context.

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One anastomosis gastric bypass (OAGB): a scoping review

Researchers from the US and Mexico have reported that although one anastomosis gastric bypass (OAGB) is an effective metabolic and bariatric procedure with favourable outcomes in weight loss and disease remission, heterogeneity in surgical techniques, outcome definitions, and limited follow-up time to assess long-term outcomes emphasise the need for standardised reporting and further high-quality long-term studies to guide patient selection and decision making.

Writing in BMC Surgery, their scoping review aimed to synthesise the current literature on OAGB, focusing on four domains: percentage excess weight loss (%EWL), remission of metabolic and cardiovascular conditions, postoperative complications, and incidence of GERD.

The identified 67 studies that showed OAGB had a higher or comparable %EWL versus Roux-en-Y gastric bypass, sleeve gastrectomy and SADI-S, particularly in short- and mid-term follow-up.

However, there was significant variability in how %EWL was defined and calculated, including inconsistent or absent definitions of ideal weight. Type 2 diabetes remission ranged from 76.8 to 100%, with meaningful improvements in hypertension, dyslipidaemia and obstructive sleep apnoea.

GERD incidence varied and was influenced by limb length, presence of hiatal hernia, and surgical technique. Longer biliopancreatic limbs enhanced weight loss but increased nutritional risk. Definitions and reporting of complications varied significantly.

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