Factors Associated With Long-Term Weight Loss Following Bariatric Surgery Using 2 Methods for Repeated Measures Analysis

Socio-Demographic and Preoperative Clinical Factors Associated With 5-Year Weight Trajectories After Roux-en-Y Gastric Bypass and Sleeve Gastrectomy

Objective

To determine whether socio-demographic and preoperative clinical factors contribute to the percent total body weight loss (%TBWL) after bariatric surgery (BS).

Background

BS is the most effective long-term treatment for medically complicated obesity. More information is needed about the factors that contribute to postoperative %TBWL in large and ethnically diverse cohorts.

Methods

This retrospective study conducted in the Kaiser Permanente Northern California region included 7698 patients who underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) between January 2009 and March 2015. Trajectory analyses were conducted from 5-year follow-up data to assign patients to "low," "average," or "high" postoperative %TBWL groups. We then evaluated whether age, sex, race/ethnicity, neighborhood deprivation index and preoperative body mass index (BMI)/weight loss, diabetes, hypertension, and sleep apnea contributed to postoperative %TBWL using logistic regression models.

Results

Of 7698 patients (83.2% women), 48.6% underwent a RYGB and 51.4% underwent a SG. Postoperative %TBWL trajectories over 5 years were obtained in 6229 (81%) of 7698 eligible patients. About 27.8% and 29.3% of patients followed the "low" postoperative %TBWL trajectory, for RYGB and SG, respectively. Men, older patients, and Asian, Black, and Hispanic/Latino patients were more likely to be classified in the low postoperative %TBWL group. Patients showing lower postoperative %TBWL had a lower preoperative BMI (but lost less weight before surgery) and were more likely to have preoperative comorbidities.

Conclusions

This study confirms and extends prior findings of the effects of several demographic and preoperative clinical factors on postoperative weight loss. Findings could improve the support of patients to achieve desired surgical outcomes.

Associations between psychological evaluation outcomes, psychiatric diagnoses, and outcomes through 12 months after bariatric surgery

BACKGROUND

There is limited evidence about how patients' initial preoperative psychological evaluation outcomes (require follow-up [RFU], no required follow-up [NFU], and place on hold [POH]) and current psychiatric diagnoses associate with postoperative outcomes.

OBJECTIVES

To test the hypotheses that patients who receive a clinical decision of RFU versus NFU from their initial psychological evaluation will be (1) more likely to experience postoperative complications, readmissions, and emergency room visits and (2) experience less weight loss over 12-months. Specific diagnoses (any psychiatric diagnosis, depression, and anxiety) are also examined for their association with weight loss over 12 months.

SETTING

Midwestern medical center, United States.

METHODS

The sample included 322 patients (81.1% female and 64.0% White) with completed psychological evaluations between August 2019 and December 2020. Patient demographics, psychological evaluation outcomes, current diagnoses, and postoperative outcomes were extracted from the health record. Bivariate analyses determined associations between NFU/RFU and postoperative complications (yes, no), readmissions (yes, no), and emergency room visits (yes, no). Mixed multilevel models were conducted with dichotomous variables NFU/RFU, any psychiatric diagnoses (yes, no), depression diagnoses (yes, no), or anxiety diagnoses (yes, no) as the main fixed within-group factors with weight loss (weight or percent total weight loss) used as the repeated measures. Insurance and surgical procedure were included as covariates.

RESULTS

There were no significant differences in postoperative complications, readmissions, and emergency room visits between NFU and RFU groups. Patients who received a RFU versus an NFU had higher weights over 12 months (P = .001).

CONCLUSION

Hypothesis 2 was only partially supported. Patients who received an RFU versus an NFU had higher weights over 12 months, but this association was not found for percent total weight loss or any of the psychiatric within-subjects variables (i.e., psychiatric diagnoses, depression, and anxiety).

Are Geographical Health Accessibility and Socioeconomic Deprivation Associated with Outcomes Following Bariatric Surgery? A Retrospective Study in a High-Volume Referral Bariatric Surgical Center

PURPOSE

Few studies have evaluated the association between non-clinical determinants (socioeconomic status and geographic accessibility to healthcare) and the outcomes of bariatric surgery, with conflicting results. This study aimed to evaluate this association.

METHODS

The medical records of 1599 consecutive patients who underwent either laparoscopic Roux-en-Y gastric bypass or laparoscopic sleeve gastrectomy between June 2005 and December 2017 were retrieved. All relevant data, including patient characteristics, biometric values before and after surgery, related medical problems, surgical history, medications, and habitus, for each patient were prospectively collected in a database. Logistic regressions were used to assess the influence of non-clinical determinants on surgical indications and complications. Multilevel linear or logistic regression was used to evaluate the influence of non-clinical determinants on long-term %TWL and the probability to achieve adequate weight loss (defined as a %TWL > 20% at 12 months).

RESULTS

Analysis of the 1599 medical records revealed that most geographically isolated patients were more likely to have undergone laparoscopic Roux-en-Y gastric bypass (odds ratio: 0.97; 95% confidence interval: 0.94 to 0.99; P = 0.018) and had a greater likelihood of adequate weight loss (β: 0.03; 95% CI: 0.01 to 0.05; P = 0.021). Conversely, socioeconomic status (measured by the European Deprivation Index) did not affect outcomes following bariatric surgery.

CONCLUSION

Geographical health isolation is associated with a higher probability to achieve adequate weight loss after 1 year of follow-up, while neither health isolation nor socioeconomic deprivation is associated with post-operative mortality and morbidity. This results suggests that bariatric surgery is a safe and effective tool for weight loss despite socioeconomic deprivation.

Racial disparities in bariatric surgery postoperative weight loss and co-morbidity resolution: a systematic review

While bariatric surgery is an accepted treatment for morbid obesity, the impact of race on surgical outcomes remains unclear. This systematic review aims to compare differences in weight loss and co-morbidity outcomes among various races after bariatric surgery. PubMed, Medline, and SCOPUS databases were queried to identify publications that included more than 1 racial group and reported weight loss outcomes after bariatric surgery. A total of 52 studies were included. Non-Hispanic black (NHB) patients comprised between 5.5% and 69.7% and Hispanic patients comprised between 4.7% and 65.3% of the studies' populations. Definitions of weight loss success differed widely across studies, with percent excess weight loss being the most commonly reported outcome, followed by percent total weight loss and change in body mass index (BMI). Statistical analyses also varied, with most studies adjusting for age, sex, preoperative weight, or BMI. Some studies also adjusted for preoperative co-morbidities, including diabetes mellitus, hypertension, and hyperlipidemia, or socioeconomic status, including income, education, and neighborhood poverty. The majority of studies found less favorable weight loss in NHB compared to Hispanic and non-Hispanic white (NHW), patients while generally no difference was found between Hispanic and NHW patients. The trend also indicates no association between race and resolution of obesity-related co-morbidities. Racial minorities lose less weight than NHW patients after bariatric surgery, although the factors associated with this discrepancy are unclear. The heterogeneity in reporting weight loss success and statistical analyses amongst the literature makes an estimation of effect size difficult. Generally, racial disparity was not seen when examining co-morbidity resolution after surgery. More prospective, robust, long-term studies are needed to understand the impacts of race on bariatric surgery outcomes and ensure successful outcomes for all patients, regardless of race.

Factors Associated with Weight Loss After Metabolic Surgery in a Multiethnic Sample of 1012 Patients

BACKGROUND

Metabolic surgery is the most effective method for weight loss in the long-term treatment of morbid obesity and its comorbidities. The primary aim of this study was to examine factors associated with percent total weight loss (%TWL) after metabolic surgery among an ethnically diverse sample of patients.

METHODS

A retrospective review was performed on 1012 patients who underwent either a sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) at our institution between January 2008 and June 2015.

RESULTS

African Americans had a lower %TWL than non-Hispanic/Latino Whites at 6, 9, 12, 18, and 48 months. At all timeframes, there was a negative association between pre-surgery TWL and %TWL after surgery. Female sex was negatively associated with %TWL at 3 months only. Higher initial BMI was also associated with greater post-operative %TWL at 18, 24 and 36 months. Older patients had lower %TWL at 6, 9, 12 and 24 months post-surgery. Patients who received RYGB had greater %TWL than those who received SG at 3, 6, 9, 12, 24 and 36 months.

CONCLUSIONS

African Americans had a lower %TWL than non-Hispanic/Latino Whites at most time points; there were no other significant race/ethnicity or sex differences. BMI (greater initial BMI), age (lower) and RYGB were associated with a greater post-operative %TWL at certain post-surgery follow-up time points. A limitation of this study is that there was missing data at a number of time points due to lack of attendance at certain follow-up visits.

Differential Metabolomic Signatures in Patients with Weight Regain and Sustained Weight Loss After Gastric Bypass Surgery: A Pilot Study

BACKGROUND

While Roux-en-Y gastric bypass (RYGB) is one of the most effective and durable treatment options for obesity and its comorbidities, it is complicated by long-term weight regain in over 20% of patients.

AIMS

We sought to determine the metabolite signatures of serum samples of patients with weight regain (RYGB-WR) after RYGB and features distinguishing these patients from patients with sustained weight loss (RYGB-SWL).

METHODS

We prospectively analyzed serum samples from 21 RYGB-WR patients, 14 RYGB-SWL patients, and 11 unoperated controls. The main outcome measure was their serum metabolite profile.

RESULTS

Weight regain after RYGB was associated with a unique serum metabolomic fingerprint. Most of the statistically different metabolites were involved in amino acid metabolism, one-carbon metabolism, and related nucleotide metabolism. A principal component analysis identified groups of metabolites that correlate with weight regain. Specifically, weight regain was associated with lower serum levels of metabolites related to the serine, glycine and threonine pathway, phenylalanine metabolism, tricyclic acid cycle, alanine and glutamate metabolism, and higher levels of other amino acids.

CONCLUSIONS

Weight regain after RYGB is associated with unique serum metabolite signatures. Metabolite profiling may eventually help us to identify markers that could differentiate the patients who will regain weight versus those who will likely sustain weight loss.

Preoperative liking and wanting for sweet beverages as predictors of body weight loss after Roux-en-Y gastric bypass and sleeve gastrectomy

Background/objectives:

Patients who receive Roux-en-Y gastric bypass (RYGB) lose more weight than those who receive vertical sleeve gastrectomy (VSG). RYGB and VSG alter hedonic responses to sweet flavor, but whether baseline differences in hedonic responses modulate weight loss after RYGB or VSG remains untested.

Participants/methods:

Male and female candidates (n=66) for RYGB or VSG were recruited and tested for their subjective liking and wanting ratings of sucrose solutions and flavored beverages sweetened with aspartame. Participants were classified by unsupervised hierarchical clustering for their liking and wanting ratings of sucrose and aspartame. Participant liking ratings were also used in a supervised classification using pre-established categories of liking ratings (liker, disliker, and inverted u-shape). Effects of categories obtained from unsupervised or supervised classification on body weight loss and their interaction with surgery type were analyzed separately at 3 and 12 months after surgery using linear models corrected for sex and age.

Results:

RYGB participants lost more body weight compared to VSG participants at 3 and 12 months after surgery (P < 0.001 for both time points). Unsupervised clustering analysis identified clusters corresponding to high and low wanting or liking ratings for sucrose or aspartame. RYGB participants in high-wanting clusters based on sucrose, but not aspartame, lost more weight than VSG at both 3 (P = 0.01) and 12 months (P = 0.03), yielding a significant cluster by surgery interaction. Categories based on supervised classification using liking ratings for sucrose or aspartame showed no significant effects on body weight loss between RYGB and VSG participants.

Conclusions:

Classification of patients into high/low wanting ratings for sucrose before surgery can predict differential body weight loss after RYGB or VSG in adults and could be used to advise on surgery type.

Anemia and Bariatric Surgery: Results of a National French Survey on Administrative Data of 306,298 Consecutive Patients Between 2008 and 2016

BACKGROUND

Bariatric surgery (BS) has grown exponentially in France, and long-term anemia due to micronutrient deficiencies has become common.

OBJECTIVES

The objective of this study was to assess the long-term risk of anemia after BS and to investigate the factors associated with the occurrence of this complication.

MATERIALS AND METHODS

Data from the French National Health Service database on patients who had undergone gastric bypass (GB), sleeve gastrectomy (SG), or adjustable gastric banding (AGB), between 2008 and 2016 were extracted. Only patients with a primary intervention were considered.

RESULTS

Data from 306,298 patients (143.733 SG, 79.188 GB, and 36.413 AGB) were analyzed. Overall, 12.930 of them (5.0%) had a diagnosis of anemia due to micronutrient deficiencies as main diagnosis or related diagnosis at time of a hospital stay between 2008 and 2016. In multivariate analysis, GB surgery, female gender, age younger than 52 years, and 25-OH vitamin D deficiency were positively associated with the occurrence of anemia whereas hospital procedural volume was negatively associated. The risk to be diagnosed with anemia after BS was 13.0% after a GB, 5.6% after a SG and 4.0% after an AGB (Log-rank p < 0.0001). The hazard ratio for anemia after GB compared to SG was 2.0 (95% CI 1.9-2.1), adjusted for age and gender.

CONCLUSION

In France, between 2008 and 2016, 5% of patients had anemia after BS. The risk to develop anemia was 2-fold higher after a GB than after a SG. Young women should be particularly aware of this long-term risk.

Setting realistic expectations for weight loss after laparoscopic sleeve gastrectomy

Introduction

Despite the clinical benefits of bariatric surgery, some patients have experienced disappointment with their weight loss. Setting realistic expectations is the key to success.

Aim

To develop a specific prediction calculator to estimate the expected body mass index (BMI) at 1 year after laparoscopic sleeve gastrectomy (LSG).

Material and methods

A retrospective analysis was performed to study 211 patients after primary LSG. Nine baseline variables were analyzed. Least angle regression (LARS) was employed for variable selection and to build the predictive model. External validation was performed on a dataset of 184 patients. To test the accuracy of the model, a Wilcoxon signed-rank test was performed between BMI estimates and the observed BMI. A linear logistic equation was used to construct the online predictive calculator.

Results

The model included three variables – preoperative BMI (β = 0.023, p < 0.001), age (β = 0.005, p < 0.001), and female gender (β = 0.116, p = 0.001) – and demonstrated good discrimination (R² = 0.672; adjusted R² = 0.664) and good accuracy (root mean squared error of estimate, RMSE = 0.124). The difference between the observed BMI and the estimated BMI was not statistically significant (median = 0.737 (–2.676, 3.254); p = 0.223). External validation confirmed good performance of the model.

Conclusions

The study revealed a useful predictive model for estimating BMI at 1 year after LSG. The model was used for development of the PREDICT BMI calculator. This tool allows one to set realistic expectations of weight loss at one year after LSG.

Long-Term Weight Loss and Metabolic Syndrome Remission after Bariatric Surgery: The Effect of Sex, Age, Metabolic Parameters and Surgical Technique - A 4-Year Follow-Up Study

INTRODUCTION

Bariatric surgery is an effective treatment for morbid obesity and its metabolic related comorbidities. However, the literature reports inconsistent results regarding weight loss (WL) and the resolution of comorbidities associated with obesity.

OBJECTIVE

We aim to evaluate long-term differences in WL between different surgical techniques and the impact of each surgical technique on metabolic parameters (type 2 diabetes mellitus [T2DM], dyslipidemia,hypertension, and metabolic syndrome). We also aim to evaluate the effect of baseline clinical characteristics in WL and in the evolution of metabolic syndrome (MetS) components. Our hypothesis is that different types of surgery have different effects on WL and the prevalence of comorbidities over time.

METHODS

We retrospectively evaluated WL and metabolic parameter remission (T2DM, dyslipidemia, hypertension, and MetS) during 4 years in 1,837 morbidly obese patients (females, 85%; age, 42.5 ± 10.6 years; BMI, 44.0 ± 5.8) who underwent bariatric surgery (Roux-en-Y gastric bypass [RYGB], laparoscopic sleeve gastrectomy [LSG], and laparoscopic adjustable gastric band [LAGB]).

RESULTS

The mean percentage of WL for RYGB, LSG, and LAGB was, respectively, 32.9 ± 8.7, 29.8 ± 9.8, and 16.2 ± 9.6 at 12 months and 30.6 ± 9.1, 22.7 ± 10.0, and 15.8 ± 10.8 at 48 months (p < 0.001), even after adjustment for baseline weight, BMI, age, and sex (p < 0.001). Women had more WL during the first 36 months (p = 0.013 and 0.007 at 12 and 36 months, respectively) and older patients had less WL compared to younger ones (p <0.001), except at 48 months. Patients with T2DM had less WL than those without diabetes after adjustment (sex, age, and surgical technique) during the same period. Patients with hypertension had less WL at 12 months (p = 0.009) and MetS at 24 months (p = 0.020) compared to those without these comorbidities. There was no significant difference regarding the presence of dyslipidemia in WL. The RYGB group showed better results for MetS resolution.

CONCLUSION

During the 4-year follow-up, RYGB was the surgical procedure that caused the highest WL and MetS resolution.

Polygenic risk score for predicting weight loss after bariatric surgery

BACKGROUND

The extent of weight loss among patients undergoing bariatric surgery is highly variable. Herein, we tested the contribution of genetic background to such interindividual variability after biliopancreatic diversion with duodenal switch.

METHODS

Percentage of excess body weight loss (%EBWL) was monitored in 865 patients over a period of 48 months after bariatric surgery, and two polygenic risk scores were constructed with 186 and 11 (PRS186 and PRS11) single nucleotide polymorphisms previously associated with body mass index (BMI).

RESULTS

The accuracy of the %EBWL logistic prediction model - including initial BMI, age, sex, and surgery modality, and assessed as the area under the receiver operating characteristics (ROC) curve adjusted for optimism (AUCadj = 0.867) - significantly increased after the inclusion of PRS186 (ΔAUCadj = 0.021; 95% CI of the difference [95% CIdiff] = 0.005-0.038) but not PRS11 (ΔAUCadj= 0.008; 95% CIdiff= -0.003-0.019). The overall fit of the longitudinal linear mixed model for %EBWL showed a significant increase after addition of PRS186 (-2 log-likelihood = 12.3; P = 0.002) and PRS11 (-2 log-likelihood = 9.9; P = 0.007). A significant interaction with postsurgery time was found for PRS186 (β = -0.003; P = 0.008) and PRS11 (β = -0.008; P = 0.03). The inclusion of PRS186 and PRS11 in the model improved the cost-effectiveness of bariatric surgery by reducing the percentage of false negatives from 20.4% to 10.9% and 10.2%, respectively.

CONCLUSION

These results revealed that genetic background has a significant impact on weight loss after biliopancreatic diversion with duodenal switch. Likewise, the improvement in weight loss prediction after addition of polygenic risk scores is cost-effective, suggesting that genetic testing could potentially be used in the presurgical assessment of patients with severe obesity.

FUNDING

Heart and Stroke Foundation of Canada (G-17-0016627) and Canada Research Chair in Genomics Applied to Nutrition and Metabolic Health (no. 950-231-580).

Predictive factors of weight regain following laparoscopic Roux-en-Y gastric bypass

BACKGROUND

Strategies to address weight recidivism following Roux-en-Y gastric bypass (RYGB) could be developed if patients at risk were identified in advance. This study aimed to determine factors that predict weight regain.

METHODS

Retrospective review was performed of patients who underwent laparoscopic RYGB at a single institution over 10 years. Group-based modeling was used to estimate trajectories of weight regain after nadir and stratify patients based on percent weight change (%WC).

RESULTS

Three trajectories were identified from 586 patients: 121 had ongoing weight loss, 343 were weight stable, and 122 regained weight. Male sex (p = 0.020) and white race (p < 0.001) were associated with stable weight or weight regain. Being from a neighborhood of socioeconomic advantage (p = 0.035) was associated with weight regain. Patients with weight regain experienced improved percent weight loss (%WL) at nadir (p < 0.001) and ΔBMI (p = 0.002), yet they had higher weight and BMI and lower %WL and ΔBMI than the other two groups during long-term follow-up. On multivariate analyses, those who regained weight were more likely from socioeconomically advantaged neighborhoods (OR 1.82, CI 1.18-2.79).

CONCLUSIONS

Several patient-related characteristics predicted an increased likelihood of weight regain. Further studies are needed to elucidate how these factors contribute to weight recidivism following bariatric surgery.

Methods Employed to Assess Weight Loss in Older Adults by Means of Electronic Medical Records: A Systematic Review

Electronic medical records (EMRs) can be used to identify and categorize weight loss in older adults, but research has not scrutinized methods for doing so. Through a modified PRISMA protocol, we systematically reviewed published methods for quantifying weight change from EMRs. Articles (all available through July 2016) were identified through PubMed and SCOPUS searches, screened, and evaluated. We abstracted relevant data and tabulated the methods to assess weight change. The 13 selected articles showed little consistency in the approach to key methodological issues: 1) time ranges assessed; 2) removal of spurious values; 3) metrics to quantify weight change; 4) number of measures needed to estimate change; 5) threshold for significant weight change; and 6) relation to ideal weight. There was essentially no consensus around how to identify and categorize weight loss. Further investigation is needed to establish scientifically validated and clinically useful algorithms, accounting for the six issues above.

rs4771122 Predicts Multiple Measures of Long-Term Weight Loss After Bariatric Surgery

We examined the association of 34 single nucleotide polymorphisms with weight loss up to 9.5 years after Roux-en-Y surgery. Participants were enrollees in the NUgene biobank with stored DNA and linked electronic health records. Ninety-five self-identified white participants underwent surgery and had follow-up weights obtained between 1 and 9.5 years after surgery. SNP rs4771122 was the variant most significantly associated with long-term weight loss after surgery in a repeated linear mixed model (p = .004) of long-term weight loss. In this model, each additional copy of the minor allele was associated with nearly 5 % greater percentage weight loss. This same SNP was also nominally significantly (p < .05) associated with weight loss trajectories, weight loss nadir, and weight loss 2 years after surgery.