Genetic Determinants of Weight Loss After Bariatric Surgery

Use of polygenic risk scores to assess weight loss after bariatric surgery: a 5-year follow-up study

BACKGROUND

Bariatric surgery (BS) is currently the most effective long-term treatment of severe obesity. However, the interindividual variability observed in surgical outcomes suggests a moderating effect of several factors, including individual genetic background. This study aimed to investigate the contribution of the genetic architecture of body mass index (BMI) to the variability in weight loss outcomes after BS.

METHODS

A total of 106 patients with severe obesity who underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy were followed up for 5 years. Changes in BMI (BMIchange) and percentage of total weight loss (%TWL) were evaluated during the postoperative period. Polygenic risk scores (PRSs), including 50 genetic variants, were calculated for each participant to determine their genetic risk of high BMI based on a previous genome-wide association study. Generalized estimating equation models were used to study the role of the individual's polygenic score and other factors on BMIchange and %TWL in the long term after surgery.

RESULTS

This study found an effect of the polygenic score on %TWL and BMIchange, in which patients with lower scores had better outcomes after surgery than those with higher scores. Furthermore, when analyzing only patients who underwent RYGB, the results were replicated, showing greater weight loss after surgery for patients with lower polygenic scores.

DISCUSSION

Our results indicate that genetic background assessed with PRSs, along with other individual factors, such as biological sex, age, and preoperative BMI, has an effect on BS outcomes and could represent a useful tool for estimating surgical outcomes in advance.

Longitudinal Profiling of Fasting Plasma Metabolome in Response to Weight-Loss Interventions in Patients with Morbid Obesity

It is well recognized that patients with severe obesity exhibit remarkable heterogeneity in response to different types of weight-loss interventions. Those who undergo Roux-en-Y gastric bypass (RYGB) usually exhibit more favorable glycemic outcomes than those who receive adjustable gastric banding (BAND) or intensive medical intervention (IMI). The molecular mechanisms behind these observations, however, remain largely unknown. To identify the plasma metabolites associated with differential glycemic outcomes induced by weight-loss intervention, we studied 75 patients with severe obesity (25 each in RYGB, BAND, or IMI). Using untargeted metabolomics, we repeatedly measured 364 metabolites in plasma samples at baseline and 1-year after intervention. Linear regression was used to examine whether baseline metabolites or changes in metabolites are associated with differential glycemic outcomes in response to different types of weight-loss intervention, adjusting for sex, baseline age, and BMI as well as weight loss. Network analyses were performed to identify differential metabolic pathways involved in the observed associations. After correction for multiple testing (q < 0.05), 33 (RYGB vs. IMI) and 28 (RYGB vs. BAND) baseline metabolites were associated with changes in fasting plasma glucose (FPG) or glycated hemoglobin (HbA1c). Longitudinal changes in 38 (RYGB vs. IMI) and 38 metabolites (RYGB vs. BAND) were significantly associated with changes in FPG or HbA1c. The identified metabolites are enriched in pathways involved in the biosynthesis of aminoacyl-tRNA and branched-chain amino acids. Weight-loss intervention evokes extensive changes in plasma metabolites, and the altered metabolome may underlie the differential glycemic outcomes in response to different types of weight-loss intervention, independent of weight loss itself.

Primary weight loss failure after Roux-en-Y gastric bypass is characterized by impaired gut-hormone mediated regulation of food intake

BACKGROUND/OBJECTIVES

After Roux-en-Y gastric bypass (RYGB) a subset of patients never obtain excess BMI loss (EBMIL) > 50% and are categorized as having primary weight loss (WL) failure. We hypothesized that postprandial concentrations of glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) would be lower in patients with primary WL failure compared with patients with successfully maintained WL. Furthermore, that inhibition of gut hormone secretions would increase ad libitum food intake less in patients with primary WL failure.

SUBJECTS/METHODS

Twenty women with primary WL failure (LowEBMIL < 50%) were individually matched to twenty women with successful WL (HighEBMIL > 60%) on age, preoperative BMI and time from RYGB. On separate days performed in a random order, patient-blinded subcutaneous injections of octreotide or saline (placebo) were followed by a fixed breakfast and an ad libitum lunch with blood sampling for appetite regulating hormones and Visual-Analogue-Scale (VAS)-scoring of hunger/satiety. Furthermore, participants underwent gene variant analysis for GLP-1, PYY and their receptors, indirect calorimetry, dual-energy X-ray absorptiometry (DXA)-scans, 4-days at-home food registration and 14-days step counting.

RESULTS

On placebo days, postprandial GLP-1, PYY and cholecystokinin (CCK) concentrations were similar between groups after breakfast. Fasting ghrelin was lower in LowEBMIL, but the postprandial suppression was similar. LowEBMIL had lower satiety VAS-scores and less suppression of hunger VAS-scores. Gene variants did not differ between groups. Octreotide diminished GLP-1, PYY, CCK and ghrelin concentrations in both groups. Octreotide did not affect ad libitum food intake in LowEBMIL (-1% [-13, 12], mean [95%CI]), while food intake increased in HighEBMIL (+23% [2,44]).

CONCLUSIONS

Primary WL failure after RYGB was not characterized by impaired secretions of appetite regulating gut hormones. Interestingly, inhibition of gut hormone secretions with octreotide only increased food intake in patients with successful WL post-RYGB. Thus, an impaired central anorectic response to gut hormones may contribute to primary WL failure after RYGB.

A nomogram based on adipogenesis-related methylation sites in intraoperative visceral fat to predict EWL% at 1 year following laparoscopic sleeve gastrectomy

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is a crucial surgical procedure for patients with obesity. However, epigenetic research in LSG is still in its infancy from the perspective of adipogenesis.

OBJECTIVES

This work aims to develop a model to predict 1 year excess weight loss percentage (EWL)% following LSG in Chinese patients with obesity by examining the DNA methylation profiles of intraoperative visceral fat.

SETTING

University hospital, Beijing, China.

METHODS

Firstly, we classified patients with obesity as either the satisfied group or unsatisfied group depending on whether their EWL% was 50% or higher at 1 year following LSG. After that, we analyzed differentially methylated sites (DMSs) between the satisfied group and unsatisfied group. DMSs were mapped to the corresponding differentially methylated genes. Then, we took the intersection of adipogenesis-related genes and differentially methylated genes and obtained adipogenesis-related DMSs. Next, hub methylation sites were identified by least absolute shrinkage and selection operator analysis. Finally, a nomogram was developed to predict EWL% of Chinese patients with obesity at 1 -year following LSG.

RESULTS

A total of 26 patients with obesity were enrolled in the study, including 13 in the satisfied group and 13 in the unsatisfied group. A total of 16 genes and 31 DMSs were involved in the adipogenesis signaling pathway. Finally, 4 hub methylation sites (cg06093355, cg00294552, cg00753924, and cg17092065) were identified and a predictive nomogram was established.

CONCLUSIONS

The predictive nomogram based on methylation sites including cg06093355, cg00294552, cg00753924, and cg17092065 can predict EWL% at 1 year following LSG in Chinese patients with obesity efficiently.

Combined Effect of Genetic Variants on Long-Term Weight Response after Bariatric Surgery

The pathophysiology of body weight control involves complex interactions between hormonal, environmental, behavioral and genetic factors. The purpose of this study was to analyze the association between single nucleotide polymorphisms (SNPs) of 13 genes encoding gastrointestinal peptides, their receptors or the proteins involved in their expression, with long-term weight response in a cohort of 375 patients undergoing bariatric surgery (BS). To evaluate weight response, we combined several variables to define specific response phenotypes six years after surgery. The study protocol was registered in ISRCTN (ID80961259). The analysis of the selected SNPs was performed via allelic discrimination using Taqman^® probes (Applied Biosystems, Foster City, CA, USA). The genotype association study was performed using the SNPstat program, with comparisons adjusted for sex, age, initial body mass index, type 2 diabetes, hypertension diagnosis and the type of surgery. We identified eight genetic variants associated with the weight response to BS, independently of the presurgery patient profile and the type of surgical technique, from which we calculated the unweighted risk score (RS) for each phenotype. The highest scoring category in each RS was significantly associated with lower weight loss (p = 0.0001) and greater weight regain (p = 0.0012) at the end of the follow-up.

Parental Obesity Predisposition and Age of Onset Associate with Poor Response to Bariatric and Metabolic Surgery

INTRODUCTION

Parental predisposition and age of onset may be independently associated with 1-year total weight loss (TWL) failure (< 20%) after metabolic-bariatric surgery (MBS).

METHODS

This cohort study includes all cases of the German StuDoQ|MBE register (2015-2019) with data on parental predisposition, obesity onset, and at least 1-year follow up after primary MBS procedures (n = 14,404). We provide descriptive statistics of the cohort in terms of the main outcome and 1-year TWL failure, and provide characteristics of surgery type subgroups. Finally, we provide a multivariate logistic regression model of 1-year TWL failure.

RESULTS

58.8% and 45.7% of patients reported maternal and paternal predisposition for obesity, respectively. Average onset of obesity was 15.5 years and duration of disease 28.3 years prior to MBS. SG is the most frequently performed procedure (47.2%) followed by RYGB (39.7%) and OAGB (13.1%). Mean 1-year TWL is 32.7 ± 9.3%, and 7.8% (n = 1,119) of patients show TWL failure (< 20%). Multivariate analysis shows independent association of early onset of obesity (< 18 years), male sex, age at operation, pre-operative BMI, pre-operative weight loss, sleeve gastrectomy (SG), and type 2 diabetes (T2D) with 1-year TWL failure (p < 0.001).

CONCLUSION

The proportions of MBS patients that report on paternal and maternal predisposition for obesity are 45.7% and 58.8% respectively, and average age at onset is 15.5 years. 7.8% of patients do not meet current target criteria of successful response to surgery at 1 year. Early onset, male sex, age at operation, pre-operative BMI, pre-operative weight loss, SG, and T2D are independently associated with weight loss failure.

Low-frequency Coding Variants Associated With Body Mass Index Affect the Success of Bariatric Surgery

CONTEXT

A recent study identified 14 low-frequency coding variants associated with body mass index (BMI) in 718 734 individuals predominantly of European ancestry.

OBJECTIVE

We investigated the association of 2 genetic scores (GS) with i) the risk of severe/morbid obesity, ii) BMI variation before weight-loss intervention, iii) BMI change in response to an 18-month lifestyle/behavioral intervention program, and iv) BMI change up to 24 months after bariatric surgery.

METHODS

The 14 low-frequency coding variants were genotyped or sequenced in 342 French adults with severe/morbid obesity and 574 French adult controls from the general population. We built risk and protective GS based on 6 BMI-increasing and 5 BMI-decreasing low-frequency coding variants that were polymorphic in our study.

RESULTS

While the risk GS was not associated with severe/morbid obesity status, BMI-decreasing low-frequency coding variants were significantly less frequent in patients with severe/morbid obesity than in French adults from the general population. Neither the risk nor the protective GS was associated with BMI before intervention in patients with severe/morbid obesity, nor did they affect BMI change in response to a lifestyle/behavioral modification program. The protective GS was associated with a greater BMI decrease following bariatric surgery. The risk and protective GS were associated with a higher and lower risk of BMI regain after bariatric surgery.

CONCLUSION

Our data indicate that in populations of European descent, low-frequency coding variants associated with BMI in the general population also affect the outcomes of bariatric surgery in patients with severe/morbid obesity.

A Clinical-Genetic Score for Predicting Weight Loss after Bariatric Surgery: The OBEGEN Study

Around 30% of the patients that undergo bariatric surgery (BS) do not reach an appropriate weight loss. The OBEGEN study aimed to assess the added value of genetic testing to clinical variables in predicting weight loss after BS. A multicenter, retrospective, longitudinal, and observational study including 416 patients who underwent BS was conducted (Clinical.Trials.gov- NCT02405949). 50 single nucleotide polymorphisms (SNPs) from 39 genes were examined. Receiver Operating Characteristic (ROC) curve analysis were used to calculate sensitivity and specificity. Satisfactory response to BS was defined as at nadir excess weight loss >50%. A good predictive model of response [area under ROC of 0.845 (95% CI 0.805–0.880), p < 0.001; sensitivity 90.1%, specificity 65.5%] was obtained by combining three clinical variables (age, type of surgery, presence diabetes) and nine SNPs located in ADIPOQ, MC4R, IL6, PPARG, INSIG2, CNR1, ELOVL6, PLIN1 and BDNF genes. This predictive model showed a significant higher area under ROC than the clinical score (p = 0.0186). The OBEGEN study shows the key role of combining clinical variables with genetic testing to increase the predictability of the weight loss response after BS. This finding will permit us to implement a personalized medicine which will be associated with a more cost-effective clinical practice.

A Systematic Review of Genetic Correlates of Weight Loss After Bariatric Surgery

This systematic review synthesized research evaluating the relationship between genetic predictors and weight loss after bariatric surgery. Fifty-seven studies were identified that examined single genes or genetic risk scores. Uncoupling protein (UCP) rs660339 was associated with excess weight loss after surgery in 4 of 6 studies. The most commonly assessed genes were fat mass and obesity-associated (FTO) gene (n = 10) and melanocortin-4 receptor (MC4R) (n = 14). Both were inconsistently related to weight loss. Genetic risk scores predicted weight loss in 6 of 7 studies. This evidence suggests the potential of using genetic variants and genetic risk scores to predict the amount of weight loss anticipated after bariatric surgery and identify patients who may be at risk for suboptimal weight reduction.

Genetic markers of abdominal obesity and weight loss after gastric bypass surgery

Background

Weight loss after bariatric surgery varies widely between individuals, partly due to genetic differences. In addition, genetic determinants of abdominal obesity have been shown to attenuate weight loss after dietary intervention with special attention paid to the rs1358980-T risk allele in the VEGFA locus. Here we aimed to test if updated genetic risk scores (GRSs) for adiposity measures and the rs1358980-T risk allele are linked with weight loss following gastric bypass surgery.

Methods

Five hundred seventy six patients with morbid obesity underwent Roux-en-Y gastric bypass. A GRS for BMI and a GRS for waist-hip-ratio adjusted for BMI (proxy for abdominal obesity), respectively, were constructed. All patients were genotyped for the rs1358980-T risk allele. Associations between the genetic determinants and weight loss after bariatric surgery were evaluated.

Results

The GRS for BMI was not associated with weight loss (β = -2.0 kg/100 risk alleles, 95% CI -7.5 to 3.3, p = 0.45). Even though the GRS for abdominal obesity was associated with an attenuated weight loss response adjusted for age, sex and center (β = -14.6 kg/100 risk alleles, 95% CI -25.4 to -3.8, p = 0.008), it was not significantly associated with weight loss after adjustment for baseline BMI (β = -7.9 kg/100 risk alleles, 95% CI -17.5 to 1.6, p = 0.11). Similarly, the rs1358980-T risk allele was not significantly associated with weight loss (β = -0.8 kg/risk allele, 95% CI -2.2 to 0.6, p = 0.25).

Discussion

GRSs for adiposity derived from large meta-analyses and the rs1358980-T risk allele in the VEGFA locus did not predict weight loss after gastric bypass surgery. The association between a GRS for abdominal obesity and the response to bariatric surgery may be dependent on the association between the GRS and baseline BMI.

Genetics of Obesity: What We Have Learned Over Decades of Research

There is a genetic component to human obesity that accounts for 40% to 50% of the variability in body weight status but that is lower among normal weight individuals (about 30%) and substantially higher in the subpopulation of individuals with obesity and severe obesity (about 60%-80%). The appreciation that heritability varies across classes of BMI represents an important advance. After controlling for BMI, ectopic fat and fat distribution traits are characterized by heritability levels ranging from 30% to 55%. Defects in at least 15 genes are the cause of monogenic obesity cases, resulting mostly from deficiencies in the leptin-melanocortin signaling pathway. Approximately two-thirds of the BMI heritability can be imputed to common DNA variants, whereas low-frequency and rare variants explain the remaining fraction. Diminishing allele effect size is observed as the number of obesity-associated variants expands, with most BMI-increasing or -decreasing alleles contributing only a few grams or less to body weight. Obesity-promoting alleles exert minimal effects in normal weight individuals but have larger effects in individuals with a proneness to obesity, suggesting a higher penetrance; however, it is not known whether these larger effect sizes precede obesity or are caused by an obese state. The obesity genetic risk is conditioned by thousands of DNA variants that make genetically based obesity prevention and treatment a major challenge.

A Genetic Risk Score for the Estimation of Weight Loss After Bariatric Surgery

BACKGROUND

Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) are the most frequent bariatric surgery procedures worldwide. In this prospective study, we examined the association of a genetic risk score (GRS) with loss of excess weight after bariatric surgery.

METHODS

A total of forty-seven morbidly obese Greek patients who underwent SG (81%) or RYGB were recruited, followed up for 2 years and genotyped. Weight loss after surgery was reported as the percentage of excess weight that was lost (%EWL) at 12 and 24 months after surgery. A GRS was constructed based on previously BMI- and WHR-related single nucleotide polymorphisms (SNPs) that were found significantly correlated with weight loss after bariatric surgery in our population. The level of post-surgery %EWL after 12 and 24 months was estimated through two multiple linear regression models that considered the effects of relevant genetic risk variants.

RESULTS

The first proposed model suggested that the predictor variables of GRS, age, and BMI had a significant effect on %EWL12m. GRS was significantly associated with %EWL12m, indicating a 4.618% decrease of %EWL12m per score unit. The second model indicated a positive correlation between %EWL24m and %EWL12m, suggesting that while post-surgery weight loss increased during the first 12 months, an increase was expected in the next 12 months as well. GRS was also significantly associated with %EWL24m, indicating approximately 3% decrease of %EWL24m per score unit.

CONCLUSION

GRS can be used in the future together with other preoperative parameters in order to predict the outcome of bariatric surgery.

Factors Affecting Metabolic Outcomes Post Bariatric Surgery: Role of Adipose Tissue

Obesity is an ever-growing public health crisis, and bariatric surgery (BS) has become a valuable tool in ameliorating obesity, along with comorbid conditions such as diabetes, dyslipidemia and hypertension. BS techniques have come a long way, leading to impressive improvements in the health of the majority of patients. Unfortunately, not every patient responds optimally to BS and there is no method that is sufficient to pre-operatively predict who will receive maximum benefit from this surgical intervention. This review focuses on the adipose tissue characteristics and related parameters that may affect outcomes, as well as the potential influences of insulin resistance, BMI, age, psychologic and genetic factors. Understanding the role of these factors may help predict who will benefit the most from BS.

Factors affecting weight loss variability in obesity

Current obesity treatment strategies include diet, exercise, bariatric surgery, and a limited but growing repertoire of medications. Individual weight loss in response to each of these strategies is highly variable. Here we review research into factors potentially contributing to inter-individual variability in response to treatments for obesity, with a focus on studies in humans. Well-recognized factors associated with weight loss capacity include diet adherence, physical activity, sex, age, and specific medications. However, following control for each of these, differences in weight loss appear to persist in response to behavioral, pharmacological and surgical interventions. Adaptation to energy deficit involves complex feedback mechanisms, and inter-individual differences likely to arise from a host of poorly defined genetic factors, as well as differential responses in neurohormonal mechanisms (including gastrointestinal peptides), metabolic efficiency and capacity of tissues, non-exercise activity thermogenesis, thermogenic response to food, and in gut microbiome. A better understanding of the factors involved in inter-individual variability in response to therapies will guide more personalized approaches to the treatment of obesity.

Does Postoperative Oral and Intestinal Microbiota Correlate with the Weight-Loss Following Bariatric Surgery?-A Cohort Study

The composition of the gastrointestinal microbiota is associated with obesity. The aim of this study was to verify if, six months after bariatric surgery, patients who achieve satisfying weight-loss after sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) have a different composition of oral and intestinal microbiota in comparison with those who do not. This prospective cohort study was conducted between November 2018 and November 2020. Participants underwent either SG or RYGB and were allocated into: Group 1—participants who achieved a percentage of excess weight loss (%EWL) of ≥ 50%, and Group 2—patients with %EWL of < 50%. The %EWL was measured 6 months following surgery. At this time, oral swabs were obtained and stool samples were provided. The endpoint was the composition of the gut microbiota. Group 1 comprised 20 participants and Group 2 comprised 11 participants. Group 1 had oral microbiota more abundant in phylum Fusobacteria and intestinal microbiota more abundant in phylum Firmicutes. Group 2 had oral microbiota was more enriched in phylum Actinobacteria and intestinal microbiota was more enriched in phylum Bacteroidetes. The compositions of the microbiota of the oral cavity and large intestine 6 months after bariatric surgery are related to the weight-loss.

Impact of weight trajectory after bariatric surgery on co-morbidity evolution and burden

Background

Bariatric surgery, such as Roux-en-Y gastric bypass [RYGB] has been shown to be an effective intervention for weight management in select patients. After surgery, different patients respond differently even to the same surgery and have differing weight-change trajectories. The present analysis explores how improving a patient’s post-surgical weight change could impact co-morbidity prevalence, treatment and associated costs in the Canadian setting.

Methods

Published data were used to derive statistical models to predict weight loss and co-morbidity evolution after RYGB. Burden in the form of patient-years of co-morbidity treatment and associated costs was estimated for a 100-patient cohort on one of 6 weight trajectories, and for real-world simulations of mixed patient cohorts where patients experience multiple weight loss outcomes over a 10-year time horizon after RYGB surgery. Costs (2018 Canadian dollars) were considered from the Canadian public payer perspective for diabetes, hypertension and dyslipidaemia. Robustness of results was assessed using probabilistic sensitivity analyses using the R language.

Results

Models fitted to patient data for total weight loss and co-morbidity evolution (resolution and new onset) demonstrated good fitting. Improvement of 100 patients from the worst to the best weight loss trajectory was associated with a 50% reduction in 10-year co-morbidity treatment costs, decreasing to a 27% reduction for an intermediate improvement. Results applied to mixed trajectory cohorts revealed that broad improvements by one trajectory group for all patients were associated with 602, 1710 and 966 patient-years of treatment of type 2 diabetes, hypertension and dyslipidaemia respectively in Ontario, the province of highest RYGB volume, corresponding to a cost difference of $3.9 million.

Conclusions

Post-surgical weight trajectory, even for patients receiving the same surgery, can have a considerable impact on subsequent co-morbidity burden. Given the potential for alleviated burden associated with improving patient trajectory after RYGB, health care systems may wish to consider investments based on local needs and available resources to ensure that more patients achieve a good long-term weight trajectory.

Preoperative considerations for the pediatric patient undergoing metabolic and bariatric surgery

To ensure successful outcomes in pediatric patients with severe obesity who undergo metabolic and bariatric surgery (MBS), a number of pre-operative patient management options should be considered. This manuscript will review the indications and contraindications of MBS and special considerations for youth who might benefit from MBS. The treatment team conducts a thorough pre-operative evaluation, assessing risks and benefits of surgical intervention, and prepares patients and families to be successful with MBS by providing education about the surgical intervention and lifestyle changes that will be necessary. This article reviews the pre-operative considerations for adolescents with severe obesity who are being considered for MBS, based upon recent clinical practice guidelines.

Comparison of Comorbidity Treatment and Costs Associated With Bariatric Surgery Among Adults With Obesity in Canada

IMPORTANCE

Information on the associations between barriers to delivery of bariatric surgery and poor weight trajectory afterward is lacking. Estimates are needed to inform decisions by administrators and clinicians to improve care.

OBJECTIVE

To estimate the difference in patient-years of treatment for diabetes, hypertension, and dyslipidemia and public-payer cost between the Canadian standard and an improved bariatric surgery care pathway.

DESIGN, SETTING, AND PARTICIPANTS

Economic evaluation of a decision analytic model comparing the outcomes of the standard care in Canada with an improved bariatric care pathway with earlier sleeve gastrectomy delivery and better postsurgical weight trajectory. The model was informed by published clinical data (101 studies) and meta-analyses (11 studies) between January and May 2019. Participants were a hypothetical 100-patient cohort with demographic characteristics derived from a Canadian study.

INTERVENTIONS

Reduction of Canadian mean bariatric surgery wait time by 2.5 years following referral and improvement of patient postsurgery weight trajectory to levels observed in other countries.

MAIN OUTCOMES AND MEASURES

Modeling weight trajectory after sleeve gastrectomy and resolution rates for comorbidities in Canada in comparison with an improved care pathway to estimate differences in patient-years of comorbidity treatment over 10 years following referral and the associated costs.

RESULTS

For the 100-patient cohort (mean [SD] 88.2% [1.4%] female; mean [SD] age, 43.6 [9.2] years; mean [SD] body mass index, 49.4 [8.2]; and mean [SD] comorbidity prevalence of 50.0% [4.1%], 66.0% [3.9%], and 59.3% [4.0%] for diabetes, hypertension, and dyslipidemia, respectively) over 10 years following referral, the improved vs standard care pathway was associated with median reduction in patient-years of treatment of 324 (95% credibility interval [CrI], 249-396) for diabetes, 245 (95% CrI, 163-356) for hypertension, and 255 (95% CrI, 169-352) for dyslipidemia, corresponding to total savings of $900 000 (95% CrI, $630 000 to $1.2 million) for public payers in the base case. Relative to standard of care, the associated reduction in costs was approximately 29% (95% CrI, 20%-42%) in the improved pathway. Sensitivity analyses demonstrated independent associations of earlier surgical delivery and various levels of postsurgical weight trajectory improvements with overall savings.

CONCLUSIONS AND RELEVANCE

This study suggests that health care burden may be decreased through improvements to delivery and management of patients undergoing sleeve gastrectomy. More data are needed on long-term patient experience with bariatric surgery in Canada to inform better estimates.