Influence of gastric bypass surgery on resting energy expenditure, body composition, physical activity, and thyroid hormones in morbidly obese patients

Incidence of Postoperative Diabetes Mellitus After Roux-en-Y Reconstruction for Gastric Cancer: Retrospective Single-Center Cohort Study

Background

Sleeve gastrectomy is an effective surgical option for morbid obesity, and it improves glucose homeostasis. In patients with gastric cancer and type 2 diabetes mellitus (DM), gastrectomy, including total gastrectomy, is beneficial for glycemic control.

Objective

This study aims to clarify the effects of gastrectomy and different reconstructive techniques on the incidence of postoperative DM in patients with gastric cancer.

Methods

This retrospective, single-center, cohort study included 715 patients without DM who underwent total gastrectomy at the Tokyo Metropolitan Bokutoh Hospital between August 2005 and March 2019. Patients underwent reconstruction by Roux-en-Y (RY) gastric bypass or other surgical techniques (OT), with DM onset determined by hemoglobin A1c levels or medical records. Analyses included 2-sample, 2-tailed t tests; χ2 tests; and the Kaplan-Meier method with log-rank tests to compare the onset curves between the RY and OT groups, along with additional curves stratified by sex. A Swimmer plot for censoring and new-onset DM was implemented.

Results

Stratified data analysis compared the RY and OT reconstruction methods. The hazard ratio was 1.52 (95% CI 1.06-2.18; P=.02), which indicated a statistically significant difference in the incidence of new-onset diabetes between the RY and OT groups in patients with gastric cancer. The hazard ratio after propensity score matching was 1.42 (95% CI 1.09-1.86; P=.009).

Conclusions

This first-of-its-kind study provides insight into how different methods of gastric reconstruction affect postoperative diabetes. The results suggest significant differences in new-onset DM after surgery based on the reconstruction method. This research highlights the need for careful surgical planning to consider potential postoperative DM, particularly in patients with a family history of DM. Future studies should investigate the role of gut microbiota and other reconstructive techniques, such as laparoscopic jejunal interposition, in developing postoperative DM.

Estimates of Resting Energy Expenditure and Total Energy Expenditure Using Predictive Equations for Individuals After Bariatric Surgery: a Systematic Review with Meta-analysis

PURPOSE

Patients after metabolic bariatric surgery (MBS) require attention to maintain energy balance and avoid weight regain. Predictive equations for resting energy expenditure (REE) and total energy expenditure (TEE) are needed since gold standard methods like calorimetry and doubly labeled water are rarely available in routine clinical practice. This study aimed to determine which predictive equation for REE and TEE has the lowest bias in subjects after MBS.

METHODS

MEDLINE, Embase, Web of Science, and CENTRAL searches were performed. Meta-analyses were performed with the data calculated by the predictive equations and measured by the gold standard methods for those equations that had at least two studies with these data. The DerSimonian and Laird random-effects model and the I2 statistic were used to quantify heterogeneity in the quantitative analyses. The risk of bias was assessed using the Joanna Briggs Institute critical appraisal checklist.

RESULTS

Seven studies were included. The present study found that the Mifflin St. Jeor (1990) equation had the lowest bias (mean difference =  - 39.71 kcal [95%CI =  - 128.97; 49.55]) for calculating REE in post-BS individuals. The Harris-Benedict (1919) equation also yielded satisfactory results (mean difference =  - 54.60 kcal [95%CI =  - 87.92; - 21.28]).

CONCLUSION

The predictive equation of Mifflin St. Jeor (1990) was the one that showed the lowest bias for calculating the REE of patients following MBS.

Identification of myokines susceptible to improve glucose homeostasis after bariatric surgery

IMPORTANCE AND OBJECTIVE

The identification of myokines susceptible to improve glucose homeostasis following bariatric surgery could lead to new therapeutic approaches for type 2 diabetes.

METHODS

Changes in the homeostasis model assessment (HOMA) test were assessed in patients before and 3 months after bariatric surgery. Changes in myokines expression and circulating levels were assessed using real-time quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). Myokines known to regulate glucose homeostasis were identified using literature (targeted study) and putative myokines using RNA-sequencing (untargeted study). A linear regression analysis adjusted for age and sex was used to search for associations between changes in the HOMA test and changes in myokines.

RESULTS

In the targeted study, brain-derived neurotrophic factor (BDNF) expression was upregulated (+30%, P = .006) while BDNF circulating levels were decreased (-12%, P = .001). Upregulated BDNF expression was associated with decreased HOMA of insulin resistance (HOMA-IR) (adjusted estimate [95% confidence interval {CI}]: -0.51 [-0.88 to -0.13], P = .010). Decreased BDNF serum levels were associated with decreased HOMA of beta-cell function (HOMA-B) (adjusted estimate [95% CI] = 0.002 [0.00002-0.0031], P = .046). In the untargeted study, upregulated putative myokines included XYLT1 (+64%, P < .001), LGR5 (+57, P< .001), and SPINK5 (+46%, P < .001). Upregulated LGR5 was associated with decreased HOMA-IR (adjusted estimate [95% CI] = -0.50 [-0.86 to -0.13], P = .009). Upregulated XYLT1 and SPINK5 were associated with increased HOMA of insulin sensitivity (HOMA-S) (respectively, adjusted estimate [95% CI] = 109.1 [28.5-189.8], P = .009 and 16.5 [0.87-32.19], P = .039).

CONCLUSIONS

Improved glucose homeostasis following bariatric surgery is associated with changes in myokines expression and circulating levels. In particular, upregulation of BDNF, XYLT1, SPINK5, and LGR5 is associated with improved insulin sensitivity. These results suggest that these myokines could contribute to improved glucose homeostasis following bariatric surgery.

STUDY REGISTRATION

NCT03341793 on ClinicalTrials.gov (https://clinicaltrials.gov/).

Evolution of the basal metabolic rate after Roux-en-Y gastric bypass: a systematic review and meta-analysis

Patients who undergo Roux-en-Y gastric bypass (RYGB) exhibit a reduction in total basal metabolic rate (BMR) after surgery, which seems to be intimately related to the amount of postoperative weight loss. The objective was to perform a systematic review and meta-analysis of the literature to determine and evaluate BMR changes after RYGB. The search was performed in certified databases, and the strategy was structured according to the PRISMA ScR. The quality evaluation of the articles included in this review was assessed with two different bias risk tools (ROBINS-I and NIH) according to each study design. Two meta-analyses were elaborated based on the results. 163 articles were selected (from 2016 to 2020), and 9 articles met the inclusion criteria. All of the selected studies evaluated only adult patients, mostly women. Postoperative BMR diminished in all of the included studies after surgery compared to preoperative values. The follow-up periods were 6, 12, 24 and 36 months. Eight articles were used for the meta-analysis after the quality assessment, a total of 434 participants. Compared to baseline values, mean postoperative reductions of 356.66 kcal/d after 6 months (p < 0.001) and 432.89 kcal/d (p < 0.001) after 1 year were observed. The BMR decreases during the first years after Roux-en-Y gastric bypass, especially during the first year postsurgery.

The effect of aging on glucose metabolism improvement after Roux-en-Y gastric bypass in type 2 diabetes rats

BACKGROUND

This study aimed to investigate the effect of aging on glucose metabolism improvement after Roux-en-Y gastric bypass (RYGB) in rat models with type 2 diabetes mellitus (T2DM).

METHODS

Twenty aged Goto-Kakizaki rats were randomly assigned into RYGB-A group and sham RYGB (SR-A) group, and 10 adult Goto-Kakizaki rats also accept RYGB procedures (RYGB-Y). Glucose metabolism, resting energy expenditure (REE), glucagon-like peptide-1 (GLP-1) and total bile acid level were measured.

RESULTS

RYGB could significantly improve glucose metabolism in aged diabetic rats. The fasting blood glucose level in the RYGB-A group decreased from 15.8 ± 1.1 mmol/l before surgery to 12.3 ± 1.5 mmol/l 16 weeks after surgery (P < 0.01), and the AUC_OGTT value decreased from 2603.9 ± 155.4 (mmol/l) min to 2299.9 ± 252.8 (mmol/l) min (P = 0.08). The decrease range of fasting blood glucose in the RYGB-A group was less than that in the RYGB-Y group (20.5% ± 6.5% vs. 40.6% ± 10.6%, P < 0.01), so is the decrease range of AUC_OGTT value (11.6% ± 14.8% vs. 38.5% ± 8.3%, P < 0.01). Moreover, at the 16th postoperative week, the increase range of REE of the RYGB-A group was lower than that of the RYGB-Y group (15.3% ± 11.1% vs. 29.1% ± 12.1%, P = 0.04). The increased range of bile acid of the RYGB-A group was less than that of the RYGB-Y group (80.2 ± 59.3 % vs.212.3 ± 139.0 %, P < 0.01). The GLP-1 level of the RYGB-A group was less than that of the RYGB-Y group (12.8 ± 3.9 pmol/L vs. 18.7 ± 5.6 pmol/L, P = 0.02). There was no significant difference between the RYGB-A group and the RYGB-Y group in the level of the triiodothyronine level.

CONCLUSIONS

RYGB could induce a glucose metabolism improvement in aged diabetic rats, and aging might moderate the effect of RYGB.

Prevalence of low skeletal muscle mass following bariatric surgery

BACKGROUND AND AIMS

Evidence on the occurrence of low skeletal muscle mass (low-SMM) following bariatric surgery (BS) as well as on the impact of low-SMM antedating BS on post-surgical body composition (BC) are scant. In this context, we aimed to prospectively evaluate the prevalence of low-SMM prior to and up to 5 years after BS, and to evaluate pre-surgical low-SMM as an independent risk factor for the presence of low-SMM after BS.

METHODS

Retrospective analysis of prospectively collected database. BC was assessed by bioelectrical impedance analysis (BIA). A BIA-based formula was used to calculate skeletal muscle mass (SMM). Class I and class II low-SMM were defined respectively as a SMM index (SMMI = SMM/height²) value between -1 and -2, or > -2 standard deviations from the gender-specific regression line of the BMI versus the SMMI relationship in our reference group.

RESULTS

A total 952 subjects were included, with BC being available for 877 (92%) subjects at 12 months and for 576 subjects (60%) at 60 months after BS. Prior to surgery, and at 12-, or at 60-months after surgery, class I and class II low-SMM was ascertained respectively in 15.6% and 4.6%, 5.3% and 1.4%, and 16.6% and 6.3% of the study participants. Logistic regression analysis showed that the occurrence of low-SMM at 12- and 60-months follow-up, was independently predicted not only by age at the time of surgery [respectively, HR: 1.052 (95% CI 1.020-1.084), p = 0.001; and 1.042 (95% CI 1.019-1.066); p < 0.001] but also by the presence of low-SMM prior to surgery [respectively, HR: 10.717 (95% CI 5.771-19.904), p < 0.001; and 5.718 (95% CI 3.572-9.153); p < 0.001].

CONCLUSIONS

Our data suggest that a low-SMM phenotype occurs not only in obesity surgery candidates but also after BS, and that low-SMM prior to surgery is an important risk factor for low-SMM throughout post-surgical follow-up.

Sympathomimetic increases resting energy expenditure following bariatric surgery: A randomized controlled clinical trial

OBJECTIVE

The aim of this study was to test the hypothesis that ephedrine + caffeine (EC) reduces the fall in resting energy expenditure (REE) following bariatric surgery.

METHODS

This 32-week, randomized, double-blinded, placebo-controlled trial included 142 patients who underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) surgery. Participants were randomized to either EC or placebo for 27 weeks, beginning 5 weeks post surgery. The primary end points were change in REE (measured), percentage of predicted REE ([measured REE/Harris-Benedict equation-predicted REE] × 100), and body composition. Secondary outcomes included change in percentage of weight. Adverse events (AEs) were recorded.

RESULTS

The reduction in REE was smaller in the EC versus the placebo group, but it was not significant. Percentage of predicted REE was increased in the EC versus the placebo group (difference, mean [SE]: 5.82 [2.29], p = 0.013). Percentage of weight (difference: -3.83 [1.39], p = 0.007) was reduced in the EC versus the placebo group. Percentage of predicted REE was increased and body weight decreased in the EC-treated participants who underwent SG compared with those who underwent SG and were treated with placebo (difference in percentage of predicted REE = 8.06 [2.83], p = 0.006; difference in weight percentage = -4.37 [1.92], p = 0.025). Percentage of fat-free mass was increased in the SG participants treated with EC versus placebo (difference: 1.31 [0.63], p = 0.042). The most common AEs were anxiety, dizziness, insomnia, and tremors. Most AEs were not different from placebo by Week 32.

CONCLUSIONS

EC enhances weight loss and reduces the fall in REE following bariatric surgery. Adrenergic symptoms mostly resolve over time.

Impact of body mass index on immunogenicity of hepatitis B vaccine in bariatric surgery candidates: A retrospective study

AIMS

Hepatitis B virus (HBV) immunization is regarded as the most effective method for the prevention of HBV infection. Various factors, including body mass index (BMI), may contribute to decreased immunization responses. This study aimed to investigate the relationship between BMI at the time of vaccination with anti-HBs levels over the following years.

METHODS

In this retrospective study, 790 vaccinated participants were recruited. Of these, individuals were selected whose hepatitis B antibody (HBsAb) information was available in 2017. The researchers contacted participants by phone to gather data regarding vaccination history, and weight at the time of vaccination. All data analysis was performed by SPSS.

RESULTS

This study included 165 eligible adults (28 males and 137 females). Among them, 79% participants were obese. Additionally, 46 (27.88%) and 119 (72.12%) had negative and positive HBsAb, respectively. There were no statistically significant differences seen across all characteristics, except for the number of HBV vaccinations between the positive and negative HBsAb groups. Multiple logistic regression also indicated no meaningful relationship between BMI and positive antibodies.

CONCLUSION

There was no relationship observed between BMI and immune response to HBV vaccine in bariatric candidates. Known risk factors (age, sex, diabetes, and the number of HBV vaccinations) were not independent predictors of the antibody response to the HBV vaccine.

Effects of body weight regain on leptin levels: A systematic review and meta-analysis

BACKGROUND

There are different changes observed before and after diet therapy, and also after weight regain. However, there is not sufficient information regarding weight regain and hormonal changes.

PURPOSE

The purpose of this study was to review the connection between weight regain and leptin concentration levels.

METHODS

MEDLINE, SCOPUS, Web of Science, and the Cochrane Library were searched for interventional articles published from January 1, 1980, to June 30, 2020. Randomized clinical trials with parallel or cross over design assessing leptin concentrations at the baseline and at the end of study were reviewed. Two independent reviewers extracted data related to study design, year of publication, country, age, gender, body mass index (BMI), duration of the following up period and mean ± SD of other intended variables.

RESULTS

Four articles were included, published between 2004 and 2016. Three of them were conducted in the US and one of them in Netherland. Sample size of the studies ranged between 25 and 148 participants. The range of following up period was from13 to 48 weeks. The age range of participants was from 34 to 44 years. Our analysis shows that weight regain could reduce leptin levels, but this change is not statistically significant.

CONCLUSION

This review suggests that weight regain may induce a non-significant reduction in leptin level. However, the limited number and great heterogeneity between the included studies may affect the presented results and there are still need to well-designed, large population studies to determine the relationship between weight regain and leptin levels.

Bariatric Surgery in Adults with Obesity: the Impact on Performance, Metabolism, and Health Indices

This systematic review summarizes current evidence on the impact of bariatric surgery (BS) on physical performance, metabolic, and health indices in adults with obesity. This systematic review suggests that BS induced significant reductions in body weight, fat mass, and fat-free mass in individuals with obesity. Additionally, BS may improve many physical fitness and health indicators. Observed improvements manifest during a distinct period of time. To date, studies on BS and performance have been small in number, nonrandomized in design, and not controlled regarding gender distribution and/or post-surgery follow-up. Future studies should further investigate concerns associated with understanding of BS outcomes to improve these outcomes with potential benefits for quality of life, disability, mortality, morbidity, and overall BS success.

Resting Energy Expenditure and Organ-Tissue Body Composition 5 Years After Bariatric Surgery

INTRODUCTION

Bariatric surgery-induced weight loss may reduce resting energy expenditure (REE) and fat-free mass (FFM) disproportionately thereby predisposing patients to weight regain and sarcopenia.

METHODS

We compared REE and body composition of African-American and Caucasian Roux-en-Y gastric bypass (RYGB) patients after surgery with a group of non-operated controls (CON). REE by indirect calorimetry; skeletal muscle (SM), trunk organs, and brain volumes by MRI; and FFM by DXA were measured at post-surgery visits and compared with CON (N = 84) using linear regression models that adjusted for relevant covariates. Ns in RYGB were 50, 42, and 30 for anthropometry and 39, 27, 17 for MRI body composition at years 1, 2, and 5 after surgery, respectively.

RESULTS

Regression models adjusted for age, weight, height, ethnicity, and sex showed REE differences (RYGB minus CON; mean ± s.e.): year 1 (43.2 ± 34 kcal/day, p = 0.20); year 2 (- 27.9 ± 37.3 kcal/day, p = 0.46); year 5 (114.6 ± 42.3 kcal/day, p = 0.008). Analysis of FFM components showed that RYGB had greater trunk organ mass (~ 0.4 kg) and less SM (~ 1.34 kg) than CON at each visit. REE models adjusted for FFM, SM, trunk organs, and brain mass showed no between-group differences in REE (- 15.9 ± 54.8 kcal/day, p = 0.8; - 46.9 ± 64.9 kcal/day, p = 0.47; 47.7 ± 83.0 kcal/day, p = 0.57, at years 1, 2, and 5, respectively).

CONCLUSIONS

Post bariatric surgery patients maintain a larger mass of high-metabolic rate trunk organs than non-operated controls of similar anthropometrics. Interpreting REE changes after weight loss requires an accurate understanding of fat-free mass composition at both the organ and tissue levels.

CLINICAL TRIAL REGISTRATION

Long-term Effects of Bariatric Surgery (LABS-2) NCT00465829.

A Comparison of the Effects of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy on Body Mass Composition as Measured by Air Displacement Plethysmography

BACKGROUND

The laparoscopic sleeve gastrectomy (LSG) is now the most commonly performed bariatric surgery in the world. Multiple studies have demonstrated the equivalence between the LSG and Roux-en-Y gastric bypass (RYGB) with regard to weight loss and comorbidity resolution. Few studies have examined the differences in body mass composition change between the two procedures.

METHODS

Sixty-three patients undergoing either LSG or RYGB underwent calculation of total body mass, ideal body mass, lean mass, and fat mass by air displacement plethysmography (BodPod^tm) prior to surgery and at 12 months postoperatively. Calculations of excess body weight, % excess weight loss, change in % fat mass, and change in % lean mass were then performed at each time interval.

RESULTS

Thirty-three patients underwent LSG and 30 patients underwent RYGB. Mean percent excess weight loss in the LSG and RYGB group was 47.2% and 53.4% respectively (p = 0.165, 95% CI - 14.8-2.6). Mean percent change in fat mass for the LSG group and RYGB group was 9.2% and 10.51% respectively (p = 0.249, 95% CI - 0.86-3.2). Mean percent change in lean mass for the LSG group and RYGB group was 9.4% and 10.49% respectively (p = 0.383, 95% CI 2.85-1.13).

CONCLUSION

The LSG and RYGB both impart dramatic meaningful loss in excess body weight. In addition, both the LSG and RYGB impart dramatic reductions in fat mass. However, both procedures induce loss of lean mass and there appears to be no difference between the two procedures in this regard despite their anatomic and physiologic differences.

Changes in serum albumin and liver enzymes following three different types of bariatric surgery: six-month follow-up. A retrospective cohort study

BACKGROUND

Few reports have examined the effects of Roux-en-Y gastric bypass (RYGB), one-anastomosis gastric bypass (OAGB) and sleeve gastrectomy (SG) on changes to serum albumin (Alb) and liver enzyme levels.

OBJECTIVE

To compare short-term post-surgery changes in serum Alb, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALKP) levels. Body composition changes were also measured and compared among three groups.

DESIGN AND SETTING

Retrospective cohort study conducted in Tehran, Iran.

METHODS

151 OAGB, RYGB and SG patients referred to the obesity clinic of Hazrat-e Rasool General Hospital, Tehran, Iran, were evaluated. Physical characteristics and biochemical parameters were measured pre-surgery and then after three and six months.

RESULTS

Through repeated measurements to determine intragroup changes, significant changes in serum AST (P = 0.003) and ALT (P < 0.001) were observed in follow-ups. However, Alb levels did not change (P = 0.413). Body fat, fat-free mass and muscle mass decreased significantly in each group (P < 0.05). In a univariate general linear model for determining intergroup changes, SG showed greater decreases in ALT and AST at three and six months (P < 0.05) and in ALKP at six months (P = 0.037), compared with OAGB. There were no significant differences in Alb levels. Also, RYGB had a greater effect on reducing fat percentage (three months, P = 0.011; six months, P = 0.059) and fat mass (three months, P = 0.042) than OAGB.

CONCLUSION

SG and RYGB may be superior to OAGB in reducing liver enzymes and body fat, respectively. However, Alb levels showed no significant differences.