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Journal Watch 01/03/2023

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 outcomes from the AMOS2 RCT, opioid use bariatric surgery, mid-term SASJ bypass results, long-term mortality after RYGB and SG, depression symptoms pre- and post-surgery and more (please note, log-in maybe required to access the full paper).

Metabolic and bariatric surgery versus intensive non-surgical treatment for adolescents with severe obesity (AMOS2): a multicentre, randomised, controlled trial in Sweden

Metabolic and bariatric surgery (MBS) is an effective and well tolerated treatment for adolescents with severe obesity resulting in substantial weight loss and improvements in several aspects of metabolic health and physical quality of life over two years, according to the outcomes of the AMOS2 randomised clinical trial.

The Adolescent Morbid Obesity Surgery 2 (AMOS2) study is a randomised, open-label, multicentre trial done at three university hospitals in Sweden (located in Stockholm, Gothenburg, and Malmö). Adolescents aged 13–16 years with a BMI of at least 35 were randomly assigned (1:1) to MBS or intensive non-surgical treatment. One group underwent MBS (primarily gastric bypass), while the other group received intensive non-surgical treatment starting with 8 weeks of low-calorie diet. The primary outcome was 2-year change in BMI, analysed as intention-to-treat.

In total, 25 (19 females and six males) were randomly assigned to receive MBS and 25 (18 females and seven males) were assigned to intensive non-surgical treatment. Three participants (6%; one in the MBS group and two in the intensive non-surgical treatment group) did not participate in the 2-year follow-up, and in total 47 (94%) participants were assessed for the primary endpoint.

After 2 years, BMI change was –12·6 kg/m2 (–35·9 kg; n=24) among adolescents undergoing MBS (Roux-en-Y gastric bypass [n=23], sleeve gastrectomy [n=2]) and –0·2 kg/m2 (0·4 kg; [n=23]) among participants in the intensive non-surgical treatment group (mean difference –12·4 kg/m2 [95% CI –15·5 to –9·3]; p<0·0001). Five (20%) patients in the intensive non-surgical group crossed over to MBS during the second year. Adverse events (n=4) after MBS were mild but included one cholecystectomy. Regarding safety outcomes, surgical patients had a reduction in bone mineral density, while controls were unchanged after 2 years (z-score change mean difference –0·9 [95% CI –1·2 to –0·6]). There were no significant differences between the groups in vitamin and mineral levels, gastrointestinal symptoms (except less reflux in the surgical group), or in mental health at the 2-year follow-up.

The Swedish researchers, writing in The Lancet Child & Adolescent Health, concluded that MBS is an effective and well tolerated treatment and should be considered in adolescents with severe obesity.

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Opioid Use After Gastric Bypass, Sleeve Gastrectomy or Intensive Lifestyle Intervention

A study by researchers led by a team from Örebro University, Örebro, Sweden, has reported Bariatric surgery was associated with a higher proportion of opioid users and larger total opioid dose, compared to actively treated people with obesity

Writing in the Annals of Surgery, the investigators compared opioid use in patients with obesity treated with bariatric surgery vs. adults with obesity who underwent intensive lifestyle modification. In the two-year period before treatment, prevalence of individuals receiving ≥1 opioid prescription was identical in the surgery and lifestyle group.

At three years, the prevalence of opioid prescriptions was 14.7% versus 8.9% in the surgery and lifestyle groups (mean difference 5.9%, 95% confidence interval 5.3–6.4) and at 8 years 16.9% versus 9.0% (7.9%, 6.8–9.0). The difference in mean daily dose also increased over time and was 3.55 mg in the surgery group versus 1.17 mg in the lifestyle group at eight years (mean difference [adjusted for baseline dose] 2.30 mg, 95% confidence interval 1.61–2.98).

These trends of higher proportion of opioid users and larger total opioid dose were especially evident in patients who received additional surgery during follow-up.

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Single-anastomosis Sleeve Jejunal: a Mid-term Follow-up Report of a New Surgical Technique

Investigators from Iran, writing in Obesity Surgery, Single anastomosis sleeve jejunal (SASJ) bypass achieved satisfactory weight loss and remissions in obesity-associated medical problems within 18 months after surgery without major complications and malnutrition.

They researchers noted that single anastomosis sleeve ileal bypass (SASI) has a high risk of malnutrition due to long biliopancreatic limb. However, SASJ bypass has a shorter limb and seems to have a lower risk of nutrient deficiency. Furthermore, this technique is relatively new, and little is known about the efficacy and safety of SASJ. Therefore, they reported their mid-term follow-up of SASJ from a high-volume centre for bariatric metabolic surgery in the country.

The paper reports 18-month of follow-up data from 43 patients with severe obesity who underwent SASJ. The primary outcome measures were demographic data, weight change variables at 6, 12, and 18 months, laboratory assessments, remission of obesity-associated medical problems, and other potential bariatric metabolic complications after the surgery.

After 18 months, patients lost 43.4±11kg of their weight and 68±14% of their excess weight, and their BMI decreased from 44.9±4.7 to 28.6±3.8kg/m2 (p<0.001). The percentage of total weight loss till 18 months was 36.3%. The T2D remission rate at 18 months was 100%. Patients neither faced deficiency in significant markers for nutrition state nor represented major bariatric metabolic surgery complications.

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Reduction in Long-term Mortality After Sleeve Gastrectomy and Gastric Bypass Compared to Nonsurgical Patients With Severe Obesity

US researchers led by University of Pittsburgh Medical Center, Pittsburgh, PA, have found there is an association with better survival following bariatric surgery in RYGB patients compared to controls and separately demonstrates that the SG operation also appears to be associated with lower mortality, compared to matched control patients with severe obesity that received usual care.

Published in the Annals of Surgery, the research is a retrospective, matched cohort study, that matched surgical to nonsurgical patients on site, age, sex, body mass index, diabetes status, insulin use, race/ethnicity, combined Charlson/Elixhauser comorbidity score, and prior health care utilization, with follow-up through September 2015. Each procedure was compared to its own control group and the two surgical procedures were not directly compared to each other.

Multivariable-adjusted Cox regression analysis investigated time to all-cause mortality (primary outcome) comparing each of the bariatric procedures to usual care. Secondary outcomes separately examined the incidence of cardiovascular-related death, cancer related-death, and diabetes related-death.

From 13,900 SG, 17,258 RYGB, and 87,965 nonsurgical patients, the five-year follow-up rate was 70.9%, 72.0%, and 64.5%, respectively. RYGB and SG were each associated with a significantly lower risk of all-cause mortality compared to nonsurgical patients at five-years of follow-up. In addition, RYGB was associated with a significantly lower five-year risk of cardiovascular-, cancer- and diabetes-related mortality.

However, there was not enough follow-up time to assess five-year cause-specific mortality in SG patients, but at 3-years follow-up, there was significantly lower risk of cardiovascular-, cancer- and diabetes-related mortality for SG patients. The authors added that these results help to inform the trade-offs between long-term benefits and risks of bariatric surgery.

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Evolution of depressive symptoms from before to 24 months after bariatric surgery: A systematic review and meta-analysis

Depressive symptom scores reduced substantially following bariatric surgery and comparable decreases occurred six to 24 months after surgery, according to the results of a study by Canadian researchers published in Obesity Reviews.

The authors sought to determine the extent depressive symptoms changed up to 24 months after bariatric surgery and how this was impacted by measurement tool and surgical procedure. Their systematic review identified 46 studies (32,342 patients).

The meta-analysis indicated a postsurgical reduction in depressive symptom scores that were significant (large effect, g = 0.804; 95% CI: 0.73–0.88, I2 = 95.7%). Subgroup analyses found that symptom reductions did not differ between the timing of follow-up periods, measurement tool and surgical procedure.

“These findings can help inform practitioners of the typical evolution of depressive symptoms following surgery and where deviations from this may require additional intervention” the authors concluded.

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Are male patients undergoing bariatric surgery less healthy than females?

Investigators from the Netherlands have reported man undergoing bariatric surgery more often suffer from obesity associated medical problems (OAMPs) than females and OAMPs are more advanced in males.

Writing in SOARD, the researchers examined a cross-sectional study of two cohorts undergoing surgery in 2013 (BS2013) and 2019 (BS2019), and a control group of patients with severe obesity from a general population (HELIUS).

Of 3244 patients included majority was female (>78.4%). Median (IQR) age and BMI in kg/m2 in males versus females was 47.0 (41.0-53.8) vs 43.0 (36.0-51.0) years and 41.5 (38.4-45.2) vs 42.3 (40.2-45.9) respectively in BS2013, and 52.0 (39.8-57.0) vs 45.0 (35.0-53.0) years and 40.4 (37.4-43.8) vs 41.3 (39.0-44.1) in BS2019 (p<0.05).

They reported males suffered from OAMPs in 71.4% and 82.0% compared to 50.2% and 56.9% of females in BS2013 and BS2019, respectively. Overall medication usage was higher in males (p=0.014). In BS2019 males exhibited a higher median Hba1c (p<0.001) and blood pressure (p=0.003) and used more antihypertensives and antidiabetics (p=0.004). Postoperative complications did not differ between males and females. In the control cohort 66.5% of males and 66.6% of females were eligible for surgery.

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Usefulness of Ultrasound in Assessing the Impact of Bariatric Surgery on Body Composition: a Pilot Study

Spanish investigators have reported musculoskeletal ultrasound (MUS) can be complementary to bioelectrical impedance (BIA) for the evaluation and the follow-up of body composition after bariatric surgery.

Writing in Obesity Surgery, the authors evaluated the usefulness of MUS to BIA in the follow-up of patients undergoing surgery in terms of body composition and quality of life (QoL). Thirty-two subjects (75% female, mean age: 49.15 ± 1.9 years) were included and fat mass (FM), lean mass (LM), and skeletal muscle index (SMI) were calculated by BIA. MUS measured subcutaneous fat (SF) and thigh muscle thickness (TMT) of the quadriceps. QoL was assessed by the Moorehead-Ardelt questionnaire. All these measurements were performed 1 month prior to BS and at 12-month follow-up.

The mean BMI decreased by 6.63 ± 1.25 kg/m2 (p=0.001) and they reported significant reductions in FM (p=0.001) and SF (p=0.007) and in LM (p=0.001) but not in SMI and TMT. They found a correlation between the FM and SF (pre-surgical, p=0.003) and between SMI and TMT (pre-surgical, p=0.03). QoL test showed significant improvement (p=0.001). In addition, a correlation between the QoL questionnaire and TMT post-surgery p=0.019) was observed. However, they did not find any statistically significant correlation between QoL assessment and SMI or LM.

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Late surgical start time is associated with increased blood transfusion following gastric bypass surgery

Researchers led by the University of Virginia Health, Charlottesville, VA, have report that gastric bypass patients with a later surgical start time (SST) had a greater incidence of postoperative blood transfusion.

Writing in PLOSone, the single-centre study investigated the effect of SST on blood transfusion after gastric bypass surgery and included all patients undergoing gastric bypass surgery from 2016 to 2021 (n=299). The primary outcome was blood transfusion and secondary outcomes included postoperative respiratory failure, length of stay, acute kidney injury, and mortality.

The univariate analysis revealed 15:00–18:43 SST was associated with an increased risk of blood transfusion (p=0.032), but not postoperative respiratory failure, acute kidney injury, length of stay or mortality. The multivariate analysis showed the only independent predictor of postoperative blood transfusion was a 15:00–18:43 SST (adjusted odds ratio 4.32, 95% confidence interval 1.06 to 15.96, c-statistic = 0.638). Receiver operating characteristic analysis demonstrated that compared to the 15:00 threshold, a 14:34 threshold predicted postoperative blood transfusion with better accuracy (sensitivity=70.0%, specificity=83.0%).

Despite having similar demographic and operative characteristics, bypass patients in the late SST cohort had a greater incidence of postoperative blood transfusion.

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