Weight-Independent Percentile Chart of 2880 Gastric Bypass Patients: a New Look at Bariatric Weight Loss Results

Weight Reduction Percentile Charts: 2-Year Follow-up Results of OAGB and RYGB Post Bariatric Surgery

PURPOSE

Using a single percentile chart provides us with high standards for the evaluation and accurate investigation of sufficient weight loss after bariatric surgery, counseling, and treating patients in an evidence-based way. Creating percentile charts of weight loss for gastric bypass is the aim of this study.

MATERIALS AND METHODS

This retrospective study was based on data from patients who underwent RYGB or OAGB from February 2008 to February 2020. The lambda-mu-sigma (LMS) method was used to estimate the reduction in body mass index (BMI) and six other metrics measured throughout post-operative follow-up. Percentile charts for various metrics have been presented for the first 2 years' post-surgery. We applied a bootstrap sampling method to evaluate percentile validity.

RESULTS

We recruited 2579 and 1943 patients who underwent OAGB (75% female) and RYGB (84% female) and were between the ages of 18 and 70 years. The preoperative BMI of patients in the OAGB group was higher than in the RYGB group. Concerning RYGB weight reduction results, the maximum percentage of excess weight loss (%EWL) occurs 18 months after surgery and is steady at 24 months. Far above 50%, EWL is achieved after 6 months. OAGB weight loss follows the same trend as RYGB; at 6 months, the %EWL values are slightly higher than RYGB.

CONCLUSIONS

We present the first bariatric weight loss percentile chart for OAGB. It allows evaluation of sufficient and insufficient weight loss at any post-operative point in a visual aspect. Furthermore, it predicts prospective outcomes and guides patient monitoring.

Evidence-Based Classification for Post-bariatric Weight Regain from a Benchmark Registry Cohort of 18,403 Patients and Comparison with Current Criteria

INTRODUCTION

There is a need for a standardized, evidence-based classification of post-bariatric weight-regain, to investigate and compare revision procedures and to advice and treat patients in an evidence-based way.

METHODS

We used standard deviations (SD) of the highest (1-2 years) and latest (> 2 years) percentage total weight loss (%TWL) results after primary bariatric surgery from the Dutch Audit for Treatment of Obesity (DATO) bariatric registry as benchmarks for (above) average (≥ - 1SD), poor (- 1SD to - 2SD) and insufficient (< - 2SD) weight loss. Weight regain maintaining (above) average weight loss was called grade 1, weight regain towards poor weight loss grade 2, towards insufficient weight loss grade 3, with subgrades 2a/3a for below average weight loss from the start, and 2b/3b for weight regain from (above) average to below average weight loss. Patient characteristics and diabetes improvement/impairment were compared. Sensitivity and specificity of 14 existing weight regain criteria were calculated.

RESULTS

We analyzed 93,465 results from 38,830 patients (77.1% gastric bypass, 22.5% sleeve gastrectomy). The - 1SD thresholds for early and late weight loss approximated 25%TWL and 20%TWL, the - 2SD threshold for late weight loss 10%TWL. Weight regain could be analyzed for 18,403 patients (2.5-5.2 years follow-up). They regained mean 6.7 kg (5.4%TWL), with 66.8% grade 1 weight regain, 7.2% grade 2a, 7.4% grade 2b, 2.1% grade 3a, and 0.6% grade 3b. There were significant differences in comorbidities, gender, age, weight regain, diabetes impairment, and diabetes improvement across grades. Weight regain criteria from literature were extremely divers. None had high sensitivity.

CONCLUSION

The DATO classification for post-bariatric weight regain combines the extent of weight regain with evidence-based endpoints of weight loss. It differentiated weight regain maintaining (above) average weight loss, two intermediate grades, gradual weight regain with below average weight loss from the start (primary non-response) and steep weight regain towards insufficient weight loss (secondary non-response). The classification is superior to existing criteria and well supported by evidence.

Is Adherence to Follow-Up After Bariatric Surgery Necessary? A Systematic Review and Meta-Analysis

The association of adherence to follow-up (FU) after laparoscopic gastric bypass - and gastric sleeve with weight loss (WL) is unclear. The aim of this study was to evaluate this association. Fourteen full text articles were included in the systematic review. Eight studies were included in the meta-analysis concerning FU up to 3 years postoperatively and 3 for the FU between 3 and 10 years postoperatively. Results showed a significant association between adherence to FU 0.5 to 3 years postoperatively and percentage excess WL (%EWL) but did not demonstrate a significant association between FU > 3 years postoperatively and total WL (%TWL). In conclusion, adherence to FU may not be associated with WL and therefore stringent lifelong FU in its current form should be evaluated.

6M50LSG Scoring System Increased the Proportion of Adequate Excess Body Weight Loss for Suspected Poor Responders After Laparoscopic Sleeve Gastrectomy in Asian Population

PURPOSE

We aimed to evaluate the efficacy of the predictive tool, 6M50LSG scoring system, to identify suspected poor responders after laparoscopic sleeve gastrectomy (LSG).

METHODS

The 6M50LSG scoring system has been applied since 2019. Suspected poor responders are defined by EBWL at 1 month < 19.5% or EBWL at 3 months < 37.7% based on the 6M50LSG scoring system. Our analysis included 109 suspected poor responders. Based on the date of LSG, the patients were separated into two groups: the 2016-2018 group (before group, BG, with regular care) and the 2019-2020 group (after group, AG, with upgrade medical nutrition therapy).

RESULTS

At the end of the study, the AG group had a significantly higher proportion of adequate weight loss, which was defined as EBWL ≥ 50% at 6 months after LSG, than that in the BG group (18.92% in BG vs. 48.57% in AG, p = 0.003). The AG group demonstrated significantly more 3-months-TWL (BG: 15.22% vs. AG: 17.54%, p < 0.001) and 6-months-TWL (BG: 21.08% vs. AG: 25.65%, p < 0.001). In multivariate analyses and adjustments, the scoring system (AG) resulted in significantly higher chances of adequate weight loss in suspected poor responders (adjusted OR 3.392, 95% CI = 1.345-8.5564, p = 0.010). One year after LSG, suspected poor responders in AG had a significantly higher weight loss than those in BG (BG vs. AG: TWL 27.17% vs. 32.20%, p = 0.014) .

CONCLUSION

This study confirmed that the 6M50LSG scoring system with upgraded medical nutrition therapy increased the proportion of suspected poor responders with adequate weight loss after LSG.

Weight Loss Results and Compliance with Follow-up after Bariatric Surgery

PURPOSE

The importance of follow-up (FU) for midterm weight loss (WL) after bariatric surgery is controversial. Compliance to this FU remains challenging. Several risk factors for loss to FU (LtFU) have been mentioned. The aim was therefore to evaluate the association between WL and LtFU 3 to 5 years postoperatively and to identify risk factors for LtFU.

MATERIALS AND METHODS

A single-center cross-sectional study in the Netherlands. Between June and October 2018, patients scheduled for a 3-, 4-, or 5-year FU appointment were included into two groups: compliant (to their scheduled appointment and overall maximally 1 missed appointment) and non-compliant (missed the scheduled appointment and at least 1 overall). Baseline, surgical, and FU characteristics were collected and a questionnaire concerning socio-economic factors.

RESULTS

In total, 217 patients in the compliant group and 181 in the non-compliant group were included with a median body mass index at baseline of 42.0 and 42.9 respectively. Eighty-eight percent underwent a laparoscopic Roux-en-Y gastric bypass. The median percentage total weight loss for the compliant and non-compliant groups was 30.7% versus 28.9% at 3, 29.3% versus 30.2% at 4, and 29.6% versus 29.9% at 5 years respectively, all p>0.05. Age, persistent comorbidities and vitamin deficiencies, a yearly salary <20,000 euro, no health insurance coverage, and not understanding the importance of FU were risk factors for LtFU.

CONCLUSION

Three to 5 years postoperatively, there is no association between LtFU and WL. The compliant group demonstrated more comorbidities and vitamin deficiencies. Younger age, not understanding the importance of FU, and financial challenges were risk factors for LtFU.

Psychological functioning and well-being before and after bariatric surgery; what is the benefit of being self-compassionate?

Objective

To investigate whether patients’ psychological well‐being (depression, quality of life, body image satisfaction) and functioning (self‐efficacy for eating and exercising behaviours and food cravings) improve 12 months after bariatric surgery and whether self‐compassion is associated with better psychological outcomes and lower weight after bariatric surgery.

Design

Longitudinal, prospective observational study.

Methods

Bariatric patients (n = 126, 77.8% female, 46.4 ± 10.8 years) completed the Self‐compassion Scale, Center for Epidemiology Studies Depression Scale, Impact of Weight on Quality‐of‐Life questionnaire, Body Image Scale, Weight Efficacy Lifestyle Questionnaire, Spinal Cord Injury Exercise Self‐Efficacy Scale, and G‐Food Craving Questionnaire pre‐operatively and 12 months post‐operatively. A medical professional measured patients’ weight during each assessment. Data were analysed using repeated measures t‐tests and multivariate regression analyses with Benjamini–Hochberg correction for multiple testing.

Results

Patients’ BMI, depression, and food cravings decreased significantly after surgery while quality of life, body image satisfaction, and self‐efficacy to exercise improved. Higher self‐compassion was associated with lower post‐operative depression, greater quality of life, higher body image satisfaction, and better self‐efficacy for eating behaviours (p‐values <.05) but not with post‐operative BMI, self‐efficacy to exercise, or food cravings.

Conclusions

Even though pre‐operative self‐compassion was not directly associated with a lower 12‐month post‐operative BMI, it had a positive relationship with patients’ post‐operative well‐being and self‐efficacy for controlling eating behaviour. In turn, this could help patients to manage their health long after bariatric surgery. Further work regarding the role of self‐compassion on long‐term health outcomes would be worthwhile.

Am I on Track? Evaluating Patient-Specific Weight Loss After Bariatric Surgery Using an Outcomes Calculator

PURPOSE

Individual weight loss outcomes after bariatric surgery can vary considerably. As a result, identifying and assisting patients who are not on track to reach their weight loss goals can be challenging.

MATERIALS AND METHODS

Using a bariatric surgery outcomes calculator, which was formulated using a state-wide bariatric-specific data registry, predicted weight loss at 1 year after surgery was calculated on 658 patients who underwent bariatric surgery at 35 different bariatric surgery programs between 2015 and 2017. Patient characteristics, postoperative complications, and weight loss trajectories were compared between patients who met or exceeded their predicted weight loss calculation to those who did not based on observed to expected weight loss ratio (O:E) at 1 year after surgery.

RESULTS

Patients who did not meet their predicted weight loss at 1 year (n = 237, 36%) had a mean O:E of 0.71, while patients who met or exceeded their prediction (n = 421, 63%) had a mean O:E = 1.14. At 6 months, there was a significant difference in the percent of the total amount of predicted weight loss between the groups (88% of total predicted weight loss for those that met their 1-year prediction vs 66% for those who did not, p < 0.0001). Age, gender, procedure type, and risk-adjusted complication rates were similar between groups.

CONCLUSION

Using a bariatric outcomes calculator can help set appropriate weight-loss expectations after surgery and also identify patients who may benefit from additional therapy prior to reaching their weight loss nadir.

A systems biology approach to understand gut microbiota and host metabolism in morbid obesity: design of the BARIA Longitudinal Cohort Study

INTRODUCTION

Prevalence of obesity and associated diseases, including type 2 diabetes mellitus, dyslipidaemia and non-alcoholic fatty liver disease (NAFLD), are increasing. Underlying mechanisms, especially in humans, are unclear. Bariatric surgery provides the unique opportunity to obtain biopsies and portal vein blood-samples.

METHODS

The BARIA Study aims to assess how microbiota and their metabolites affect transcription in key tissues and clinical outcome in obese subjects and how baseline anthropometric and metabolic characteristics determine weight loss and glucose homeostasis after bariatric surgery. We phenotype patients undergoing bariatric surgery (predominantly laparoscopic Roux-en-Y gastric bypass), before weight loss, with biometrics, dietary and psychological questionnaires, mixed meal test (MMT) and collect fecal-samples and intra-operative biopsies from liver, adipose tissues and jejunum. We aim to include 1500 patients. A subset (approximately 25%) will undergo intra-operative portal vein blood-sampling. Fecal-samples are analyzed with shotgun metagenomics and targeted metabolomics, fasted and postprandial plasma-samples are subjected to metabolomics, and RNA is extracted from the tissues for RNAseq-analyses. Data will be integrated using state-of-the-art neuronal networks and metabolic modeling. Patient follow-up will be ten years.

RESULTS

Preoperative MMT of 170 patients were analysed and clear differences were observed in glucose homeostasis between individuals. Repeated MMT in 10 patients showed satisfactory intra-individual reproducibility, with differences in plasma glucose, insulin and triglycerides within 20% of the mean difference.

CONCLUSION

The BARIA study can add more understanding in how gut-microbiota affect metabolism, especially with regard to obesity, glucose metabolism and NAFLD. Identification of key factors may provide diagnostic and therapeutic leads to control the obesity-associated disease epidemic.

Interpretation of laboratory results after gastric bypass surgery: the effects of weight loss and time on 30 blood tests in a 5-year follow-up program

BACKGROUND

Long-term follow-up with blood tests is essential for bariatric surgery to be a successful treatment for obesity and related co-morbidities. Adverse effects, deficiencies, and metabolic improvements need to be controlled.

OBJECTIVE

We investigated the effects of time and weight loss on laboratory results in each postoperative phase after laparoscopic Roux-en-Y gastric bypass (LRYGB).

SETTING

Bariatric center of excellence, general hospital, Netherlands.

METHODS

We retrospectively evaluated results of 30 blood tests, preoperatively and at 6 months, 1 year, 2 years, and 5 years after LRYGB. The 2019 Dutch bariatric chart was used to define weight loss responses as outstanding (>p[percentile curve]+1 SD), average (p+1 SD to p-1 SD), and poor (<p-1 SD). Results are presented with fifth and 95th percentile cutoff values per blood test for each of these 3 weight loss responses at each of the 4 postoperative time intervals. We used ANOVA to determine mutual relations.

RESULTS

Results of 4835 patients were analyzed. Five-year follow-up was 58%. Blood levels of ferritin, mean-corpuscular-volume, thrombocytes, vitamin D, parathyroid-hormone, glycated hemoglobin (HbA1C), triglyceride, total-cholesterol, C-reactive-protein, gamma-glutamyl-transferase, alkaline-phosphatase, creatinine, vitamin B1, and total protein were related with weight loss response. All 30 blood tests were also related with time. For several blood tests, weight loss and time did not only influence median results, but also fifth and 95th percentile cutoff values. Many patients had better vitamin levels after the operation. We observed an increase of parathyroid-hormone and ongoing iron depletion up to 5 years post surgery.

CONCLUSIONS

Presenting results of 30 routine blood tests, including cutoff values based on fifth and 95th percentile, grouped by weight loss response and postoperative time interval after gastric bypass surgery is new. The elaborate tables and graphs could serve as practical guide for proper interpretation of laboratory results in postbariatric surveillance. Results underline the need for long-term follow-up, including blood tests.

Check point to get adequate weight loss within 6-months after laparoscopic sleeve gastrectomy for morbid obesity in Asian population

Purpose of this study is to develope a scoring system to predict the likelihood of excess body weight loss (EBWL) ≥ 50% 6-months after laparoscopic sleeve gastrectomy (LSG). From April 2016 to September 2018, data was collected from 160 patients (BMI ≥ 32) who underwent primary LSG with at least 6-months follow-up. They were separated into score generation (operated by one surgeon, n = 122) and validation groups (operated by 3 different surgeons, n = 38). EBWL at 6-months ≥ 50% was considered adequate weight loss. Independent variables including age, gender, initial body mass index (BMI), comorbidities, life-style habits, percentage of EBWL and percentage of total body weight loss at 1-week, 1-month, and 3-months were analyzed with mutivariate logistic regression to generate the scoring system. The system was applied to internal and external validation groups to determine efficacy. As results, between the score generation and internal validation groups, the only significant difference in patient characteristics was in exercise participation. EBWL at 1-month > 19.5% (1 point) and EBWL at 3-months > 37.7% (2 points) were identified as independent factors to predict EBWL at 6-months ≥ 50%. When scores were > 1, the system had 94.03% positive predictive value (PPV) and 81.82% negative predictive value (NPV) (AUC: 0.923). Internal validation scores > 1 had a 95.83% PPV and 85.71% NPV (AUC: 0.975). External validation results showed 88.59% PPV and 72.00% NPV (AUC: 0.802). We concluded that this scoring system provides a reliable, objective prediction of EBWL at 6-months ≥ 50%. Patients requiring more aggressive clinical follow-up and intervention can be detected as early as 1- to 3-months after LSG.

Timing of Maximal Weight Reduction Following Bariatric Surgery: A Study in Chinese Patients

Introduction: Bariatric surgery is a well-received treatment for obesity with maximal weight loss at 12-36 months postoperatively. We investigated the effect of early bariatric surgery on weight reduction of Chinese patients in accordance with their preoperation characteristics. Materials and Methods: Altogether, 409 patients with obesity from a prospective cohort in a single bariatric center were enrolled retrospectively and evaluated for up to 4 years. Measurements obtained included surgery type, duration of diabetic condition, besides the usual body mass index data tuple. Weight reduction was expressed as percent total weight loss (%TWL) and percent excess weight loss (%EWL). Results: RYGB or SG were performed laparoscopically without mortality or complications. BMI generally plateaued at 12 months, having decreased at a mean of 8.78 kg/m². Successful weight loss of >25% TWL was achieved by 35.16, 49.03, 39.22, 27.74, 20.83% of patients at 6, 12, 24, 36, and 48 months after surgery. Overall, 52.91% of our patients had lost 100% of their excess weight at 12 months, although there was a rather wide range among individuals. Similar variability was revealed in women of child-bearing age. Conclusion: Chinese patients undergoing bariatric surgery tend to achieve maximal weight loss and stabilization between 12 and 24 months postoperatively, instead of at >2 years. The finding of the shorter stabilization interval has importance to earlier intervention of weight loss related conditions and women's conception planning.

Sensitivity and Specificity of 50% Excess Weight Loss (50%EWL) and Twelve Other Bariatric Criteria for Weight Loss Success

BACKGROUND

Criteria for bariatric weight loss success are numerous. Most of them are arbitrary. None of them is evidence-based. Our objective was to determine their sensitivity and specificity.

METHODS

Thirteen common bariatric weight loss criteria were compared to a benchmark reflecting the gold standard in bariatric surgery. We used an elaborate baseline BMI-independent weight loss percentile chart, based on retrospective data after laparoscopic Roux-en-Y gastric bypass (LRYGB), performed between 2007 and 2017. Percentile curves p31.6 (patients' expectation), p25 (interquartile range), p15.9 (1 standard deviation (SD) below median), and p10.9 (surgeons' goal) were used as possible cutoff for success to determine true or false positive and negative results beyond 1 year.

RESULTS

We operated 4497 primary LRYGB patients, with mean follow-up 22 (± 1 SD 19; range 0-109) months, 3031 patients with last result ≥ 1 year, 518 ≥ 5 years. For all four cutoff percentile curves for success, specificities were low (2-72%) for criteria < 35 body mass index (BMI), ≥ 25percentage excess BMI loss (%EBMIL), ≥ 50%EBMIL, ≥ 15 percentage total weight loss (%TWL), ≥ 20%TWL, ≥ 25 percentage excess weight loss (%EWL), and high (83-96%) for < 30 BMI. No criterion had > 80% specificity and sensitivity for a cutoff above p15.9. For p15.9, they were both > 80% for criteria ≥ 10 BMI reduction and ≥ 50%EWL, both > 90% for ≥ 25%TWL and ≥ 35 percentage alterable weight loss (%AWL). All criteria had high sensitivities for all cutoff percentile curves (87-100%), except < 30 BMI (65-78%).

CONCLUSIONS

For the first time, common bariatric criteria for weight loss success were systematically validated. Most criteria recognized success very well (high sensitivities), but ≥ 15%TWL, ≥ 20%TWL, < 35BMI, ≥ 25%EWL, ≥ 25%EBMIL, and ≥ 50%EBMIL left too many poor responders unnoticed (low specificities). Bariatric weight loss success is best assessed by comparing results to percentile curve 1 SD below median (p15.9) in a bariatric baseline BMI-independent weight loss percentile chart. Criteria ≥ 35%AWL and ≥ 25%TWL came close to that curve, both with > 90% sensitivity and specificity. Among others, criterion ≥ 50%EBMIL did not.

Perceived Postoperative Support Differentiates Responders from Non-Responders 3 Years After Laparoscopic Roux-en-Y Gastric Bypass

BACKGROUND

Bariatric surgery is an effective intervention for the majority of patients with morbid obesity, but a significant minority fails to achieve substantial weight loss. In the search of possible predictors of weight loss following bariatric surgery, preoperative factors turn out to have limited predictive power. This study will examine the impact of two postoperative factors on weight loss: perceived social support and stressful life events.

METHODS

From the entire 2013 cohort that underwent laparoscopic Roux-and-Y gastric bypass (LRYGB) in a general hospital in the Netherlands, a group of 56 non-responders and a matched group of 56 responders were selected, using an alterable weight loss (%AWL)-based percentile chart. Patients from both groups were interviewed by phone to collect data on demographics, medical complications and comorbidities, social support and stressful life events. A total of 61 patients completed the data collection (54% response rate).

RESULTS

One-way ANOVA analysis showed that responders and non-responders differed with regard to perceived support (F(1) = 8.60, p = .005). In a model with place of birth, level of education and pre-surgery diabetes mellitus as covariates, perceived social support was able to classify 83.6% of patients correctly as either responder or non-responder (χ ² = 28.26, p < .001). Stressful life events turned out to be unrelated to weight loss.

CONCLUSIONS

Perceived social support differentiates responders from non-responders after LRYGB. When patients present themselves after LRYGB with sub-optimal weight loss, social support should be a focus of attention.

Long-term weight loss in laparoscopic sleeve gastrectomy

INTRODUCTION

Laparoscopic sleeve gastrectomy (LSG) has become an option as a bariatric surgical technique. There is a lack of long-term results of this procedure in the literature. The aim of this study is to present weight loss results of LSG for up to 7 years of follow-up.

METHODS

A retrospective series of patients who underwent LSG between 2008 and 2011 was examined. The primary endpoint was weight loss: percentage of excess weight loss (%EWL), percentage of total weight loss (%TWL), and body mass index (BMI) were reported. Failure was defined as %EWL<50%. Multivariate analysis for weight loss was performed. The complications rate was reported.

RESULTS

A total of 148 patients met the inclusion criteria; 76.3% were female. Mean preoperative BMI was 36 ± 4 kg/m². Mean operative time was 89.3 ± 3.2 minutes. Follow-up at 5, 6, and 7 years was 77.7%, 83.3%, and 82.2%, respectively. Mean %EWL and %TWL at 1, 3, 5, and 7 years was 93.2%, 80.7%, 70.6%, and 51.7%, and 27.2%, 23.3%, 20.4%, and 16.3%, respectively. The failure rate was 30.4% at the fifth year and 51.4% at the seventh year. High preoperative BMI was related to worse %EWL (P<0.001) but not to %TWL. Preoperative BMI<35 kg/m² was associated with better %EWL but not with %TWL (P = 0.003). Four leaks (2.7%) and no mortalities were reported.

CONCLUSIONS

LSG is an acceptable surgical technique for weight loss, but in this series, up to one third of the patients fail at the fifth year and half fail in the seventh year. %EWL is better in patients with BMI<35 kg/m², but this difference disappears when we express outcomes with %TWL.