Effect of Bariatric Surgery on Long-Term Cardiovascular Outcomes: A Systematic Review and Meta-analysis of Population-Based Cohort Studies

Estimating the Effect of Bariatric Surgery on Cardiovascular Events Using Observational Data?

BACKGROUND

Observational studies have reported strongly protective effects of bariatric surgery on cardiovascular disease, but with oversimplified definitions of the intervention, eligibility criteria, and follow-up, which deviate from those in a randomized trial. We describe an attempt to estimate the effect of bariatric surgery on cardiovascular disease without introducing these sources of bias, which may not be entirely possible with existing observational data.

METHODS

We propose two target trials among persons with diabetes: (1) bariatric operation (vs. no operation) among individuals who have undergone preoperative preparation (lifestyle modifications and screening) and (2) preoperative preparation and a bariatric operation (vs. neither preoperative nor operative component). We emulated both target trials using observational data of US veterans.

RESULTS

Comparing bariatric surgery with no surgery (target trial #1; 8,087 individuals), the 7-year cardiovascular risk was 18.0% (95% CI = 6.9, 32.7) in the surgery group and 18.9% (95% CI = 17.7, 20.1) in the no-surgery group (risk difference -0.9, 95% CI = -12.0, 14.0). Comparing preoperative components plus surgery vs. neither (target trial #2; 10,065 individuals), the 7-year cardiovascular risk was 17.4% (95% CI = 13.6, 22.0) in the surgery group and 18.8% (95% CI = 17.8, 19.9) in the no-surgery group (risk difference -1.4, 95% CI = -5.1, 3.2). Body mass index and hemoglobin A1c were reduced with bariatric interventions in both emulations.

CONCLUSIONS

Within limitations of available observational data, our estimates do not provide evidence that bariatric surgery reduces cardiovascular disease and support equipoise for a randomized trial of bariatric surgery for cardiovascular disease prevention.

Incretin-based therapies for the management of cardiometabolic disease in the clinic: Past, present, and future

Among newer classes of drugs for type 2 diabetes mellitus (T2DM), glucagon-like peptide 1 receptor agonists (GLP-1 RAs) are incretin-based agents that lower both blood sugar levels and promote weight loss. They do so by activating pancreatic GLP-1 receptors (GLP-1R) to promote glucose-dependent insulin release and inhibit glucagon secretion. They also act on receptors in the brain and gastrointestinal tract to suppress appetite, slow gastric emptying, and delay glucose absorption. Phase 3 clinical trials have shown that GLP-1 RAs improve cardiovascular outcomes in the setting of T2DM or overweight/obesity in people who have, or are at high risk of having atherosclerotic cardiovascular disease. This is largely driven by reductions in ischemic events, although emerging evidence also supports benefits in other cardiovascular conditions, such as heart failure with preserved ejection fraction. The success of GLP-1 RAs has also seen the evolution of other incretin therapies. Tirzepatide has emerged as a dual glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 RA, with more striking effects on glycemic control and weight reduction than those achieved by isolated GLP-1R agonism alone. This consists of lowering glycated hemoglobin levels by more than 2% and weight loss exceeding 15% from baseline. Here, we review the pharmacological properties of GLP-1 RAs and tirzepatide and discuss their clinical effectiveness for T2DM and overweight/obesity, including their ability to reduce adverse cardiovascular outcomes. We also delve into the mechanistic basis for these cardioprotective effects and consider the next steps in implementing existing and future incretin-based therapies for the broader management of cardiometabolic disease.

Prevalence of Obesity-Related Disease in a Danish Population - The Results of an Algorithm-Based Screening Program

Purpose

The prevalence of obesity continues to rise. People with obesity are at increased risk of several diseases. We tested an algorithm-based screening program for people with a BMI above 30 kg/m2 and present data on the prevalence of previously undiagnosed obesity-related diseases.

Patients and Methods

Seven hundred and sixty-nine persons with BMI > 30 kg/m2 and age 18-60 years were screened for diabetes (assessed by glycosylated hemoglobin and oral glucose tolerance test at HbA1c 43-48 mmol/mol), sleep apnea (screened by questionnaires and assessed by cardiorespiratory monitoring at indication of sleep disorder), liver steatosis or liver fibrosis (assessed by biochemistry and fibroscan) and arterial hypertension (assessed by both office and 24-hour blood pressure measurement). A reference group of people with a BMI of 18.5-29.9 kg/m2 was established.

Results

Of those referred, 73.0% were women. We identified new diabetes in 4.2%, prediabetes in 9.1%, moderate-to-severe sleep apnea in 25.1%, increased liver fat and increased liver stiffness in 68.1% and 17.4%, respectively, and hypertension or masked hypertension in 19.0%. The prevalence of diseases was much higher among men and increased with BMI. Except for hypertension, we found few participants with undiagnosed disease in the reference group.

Conclusion

An algorithm-based screening program is feasible and reveals undiagnosed obesity-related disease in a large proportion of the participants. The disproportional referral pattern calls for a tailored approach aiming to include more men with obesity.

Trial Registration

Inclusion of the non-obese group was approved by the Scientific Ethics Committee of The Region of Southern Denmark (project identification number: S-20210091), and the study was reported at clinicaltrials.gov (NCT05176132).

Long-term clinical outcomes of bariatric surgery in adults with severe obesity: A population-based retrospective cohort study

BACKGROUND

Bariatric surgery leads to sustained weight loss in a majority of recipients, and also reduces fasting insulin levels and markers of inflammation. We described the long-term associations between bariatric surgery and clinical outcomes including 30 morbidities.

METHODS

We did a retrospective population-based cohort study of 304,157 adults with severe obesity, living in Alberta, Canada; 6,212 of whom had bariatric surgery. We modelled adjusted time to mortality, hospitalization, surgery and the adjusted incidence/prevalence of 30 new or ongoing morbidities after 5 years of follow-up.

RESULTS

Over a median follow-up of 4.4 years (range 1 day-22.0 years), bariatric surgery was associated with increased risk of hospitalization (HR 1.46, 95% CI 1.41,1.51) and additional surgery (HR 1.42, 95% CI 1.32,1.52) but with a decreased risk of mortality (HR 0.76, 95% CI 0.64,0.91). After 5 years (median of 9.9 years), bariatric surgery was associated with a lower risk of severe chronic kidney disease (HR 0.45, 95% CI 0.27,0.75), coronary disease (HR 0.49, 95% CI 0.33,0.72), diabetes (HR 0.51, 95% CI 0.47,0.56), inflammatory bowel disease (HR 0.55, 95% CI 0.37,0.83), hypertension (HR 0.70, 95% CI 0.66,0.75), chronic pulmonary disease (HR 0.75, 95% CI 0.66,0.86), asthma (HR 0.79, 95% 0.65,0.96), cancer (HR 0.79, 95% CI 0.65,0.96), and chronic heart failure (HR 0.79, 95% CI 0.64,0.96). In contrast, after 5 years, bariatric surgery was associated with an increased risk of peptic ulcer (HR 1.99, 95% CI 1.32,3.01), alcohol misuse (HR 1.55, 95% CI 1.25,1.94), frailty (HR 1.28, 95% 1.11,1.46), severe constipation (HR 1.26, 95% CI 1.07,1.49), sleep disturbance (HR 1.21, 95% CI 1.08,1.35), depression (HR 1.18, 95% CI 1.10,1.27), and chronic pain (HR 1.12, 95% CI 1.04,1.20).

INTERPRETATION

Bariatric surgery was associated with lower risks of death and certain morbidities. However, bariatric surgery was also associated with increased risk of hospitalization and additional surgery, as well as certain other morbidities. Since values and preferences for these various benefits and harms may differ between individuals, this suggests that comprehensive counselling should be offered to patients considering bariatric surgery.

Presurgery health influences outcomes following vertical sleeve gastrectomy in adolescents

OBJECTIVE

Weight loss following vertical sleeve gastrectomy (VSG) in youth can range from 10% to 50%. We examined whether there are differences in demographic or metabolic parameters before VSG in youth who achieve above-average weight loss (AAWL) versus below-average weight loss (BAWL) at 1 year post VSG and if youth with BAWL still achieve metabolic health improvements at 1 year post VSG.

METHODS

Demographic, anthropometric, and clinical lab data were collected before VSG and at 1, 3, 6, and 12 months after VSG.

RESULTS

Forty-three youth with a mean age of 16.9 (SD 1.7) years before VSG were studied; 70% were female, 19% non-Hispanic Black, 58% non-Hispanic White, and 23% mixed/other race. Mean baseline BMI was 51.1 (SD 10.5) kg/m2. Average weight loss was 25.8%. The AAWL group lost 18.6 kg/m2 (35.3%) versus the BAWL group, who lost 8.8 kg/m2 (17.5%). BMI, age, race, sex, and socioeconomic status at baseline were similar between AAWL and BAWL groups; however, the BAWL group had a higher frequency of pre-VSG dysglycemia, steatotic liver disease, and dyslipidemia. At 1 year post VSG, fewer youth in the BAWL group achieved ideal health parameters, and they had less resolution of comorbidities.

CONCLUSIONS

The presence of comorbidities before VSG is associated with less weight loss and reduced resolution of metabolic conditions at 1 year post VSG.

IFSO Consensus on Definitions and Clinical Practice Guidelines for Obesity Management-an International Delphi Study

INTRODUCTION

This survey of international experts in obesity management was conducted to achieve consensus on standardized definitions and to identify areas of consensus and non-consensus in metabolic bariatric surgery (MBS) to assist in an algorithm of clinical practice guidelines for the management of obesity.

METHODS

A three-round Delphi survey with 136 statements was conducted by 43 experts in obesity management comprising 26 bariatric surgeons, 4 endoscopists, 8 endocrinologists, 2 nutritionists, 2 counsellors, an internist, and a pediatrician spanning six continents over a 2-day meeting in Hamburg, Germany. To reduce bias, voting was unanimous, and the statements were neither favorable nor unfavorable to the issue voted or evenly balanced between favorable and unfavorable. Consensus was defined as ≥ 70% inter-voter agreement.

RESULTS

Consensus was reached on all 15 essential definitional and reporting statements, including initial suboptimal clinical response, baseline weight, recurrent weight gain, conversion, and revision surgery. Consensus was reached on 95/121 statements on the type of surgical procedures favoring Roux-en-Y gastric bypass, sleeve gastrectomy, and endoscopic sleeve gastroplasty. Moderate consensus was reached for sleeve gastrectomy single-anastomosis duodenoileostomy and none on the role of intra-gastric balloons. Consensus was reached for MBS in patients > 65 and < 18 years old, with a BMI > 50 kg/m2, and with various obesity-related complications such as type 2 diabetes, liver, and kidney disease.

CONCLUSIONS

In this survey of 43 multi-disciplinary experts, consensus was reached on standardized definitions and reporting standards applicable to the whole medical community. An algorithm for treating patients with obesity was explored utilizing a thoughtful multimodal approach.

Cardiovascular Effects of Weight Loss in Obese Patients with Diabetes: Is Bariatric Surgery the Additional Arrow in the Quiver?

Obesity is an increasingly widespread disease worldwide because of lifestyle changes. It is associated with an increased risk of cardiovascular disease, primarily type 2 diabetes mellitus, with an increase in major cardiovascular adverse events. Bariatric surgery has been shown to be able to reduce the incidence of obesity-related cardiovascular disease and thus overall mortality. This result has been shown to be the result of hormonal and metabolic effects induced by post-surgical anatomical changes, with important effects on multiple hormonal and molecular axes that make this treatment more effective than conservative therapy in determining a marked improvement in the patient's cardiovascular risk profile. This review, therefore, aimed to examine the surgical techniques currently available and how these might be responsible not only for weight loss but also for metabolic improvement and cardiovascular benefits in patients undergoing such procedures.

Comprehensive Cardiovascular and Renal Protection in Patients with Type 2 Diabetes

Type 2 diabetes (T2DM) is one of the main public health care problems worldwide. It is associated with a marked increased risk of developing atherosclerotic vascular disease, heart failure, chronic kidney disease and death. It is essential to act during the early phases of the disease, through the intensification of lifestyle changes and the prescription of those drugs that have been shown to reduce these complications, with the aim not only of achieving an adequate metabolic control, but also a comprehensive vascular risk control. In this consensus document, developed by the different specialists that treat these patients (endocrinologists, primary care physicians, internists, nephrologists and cardiologists), a more appropriate approach in the management of patients with T2DM or its complications is provided. A particular focus is given to the global control of cardiovascular risk factors, the inclusion of weight within the therapeutic objectives, the education of patients, the deprescription of those drugs without cardiovascular benefit, and the inclusion of GLP-1 receptor agonists and SGLT2 inhibitors as cardiovascular protective drugs, at the same level as statins, acetylsalicylic acid, or renin angiotensin system inhibitors.

Remission with an Intervention: Is Metabolic Surgery the Ultimate Solution?

Long-term remission of type 2 diabetes following lifestyle intervention or pharmacotherapy, even in patients with mild disease, is rare. Long-term remission following metabolic surgery however, is common and occurs in 23% to 98% depending on disease severity and type of surgery. Remission after surgery is associated with excellent glycemic control without reliance on pharmacotherapy, improvements in quality of life, and major reductions in microvascular and macrovascular complications. For patients with type 2 diabetes, early intervention with metabolic surgery, when beta cell function still remains intact, provides the greatest probability of long-term remission as high as 90% or more.

Semaglutide for cardiovascular event reduction in people with overweight or obesity: SELECT study baseline characteristics

OBJECTIVE

This paper describes the baseline characteristics of the Semaglutide Effects on Heart Disease and Stroke in Patients with Overweight or Obesity (SELECT) study, one of the largest cardiovascular (CV) outcome studies in the field of obesity, which evaluates the effect of semaglutide versus placebo on major CV events.

METHODS

SELECT enrolled individuals with overweight or obesity without diabetes, with prior myocardial infarction, stroke, and/or peripheral artery disease. This study reports participants' baseline characteristics in the full study population and subgroups defined by baseline glycated hemoglobin (HbA_1c ; <5.7%, ≥5.7 to <6.0%, ≥6.0 to <6.5%), baseline waist to height ratio tertile, and qualifying prior CV event or condition.

RESULTS

The study enrolled 17,605 participants (72.5% male) with an average (SD) age of 61.6 (8.9) years and BMI of 33.34 (5.04) kg/m² . The most common prior CV event was myocardial infarction (76.3% of participants), followed by stroke (23.3%) and peripheral artery disease (8.6%). Furthermore, 24.3% had a heart failure diagnosis. Two-thirds of participants (66%) had HbA_1c in the prediabetes range (5.7%-6.4%). Across groups of increasing HbA_1c , prevalence of all CV risk factors increased.

CONCLUSIONS

The enrolled population in SELECT includes participants across a broad range of relevant risk categories. This will allow the study to garner information about the CV benefits of semaglutide across these relevant clinical subgroups.

META‐ANALYSIS OF PATIENT RISK FACTORS ASSOCIATED WITH POST‐BARIATRIC SURGERY LEAK

Objective

Modifiable risk factors such as diabetes, hyperlipidemia, hypertension, obstructive sleep apnea (OSA), chronic kidney disease (CKD), chronic steroid use and smoking, have been shown in observational studies to negatively affect surgical outcomes. The purpose of this study is to identify and determine the effect of modifiable risk factors on post-operative bariatric surgery leak, as pre-operative risk modification has been shown to reduce the impact on complications.

Methods

Electronic literature searches of MEDLINE, PUBMED, OVID and Cochrane Library databases were performed, including a manual reference check, over the period of 2010 and 2020. 620 articles were screened according to the PRISMA protocol.

Results

Twenty articles were included in the meta-analysis of risk factors. Significant risk factors and the associated effect sizes include: 1. Smoking with an overall OR of 1.31 [1.06, 1.61] and an OR of 1.72 [1.44, 2.05] in Sleeve gastrectomy (SG) patient cohorts; 2. Diabetes with an overall OR of 1.23 [1.08, 1.39] and an OR of 1.33 [1.02, 1.73] in Roux-en-Y patient cohorts; 3. Chronic kidney disease with an overall OR of 2.41 [1.62, 3.59] and 4. Steroid use with an overall OR of 1.57 [1.22, 2.02]. Non-significant risk factors include hypertension with an OR of 0.85, 1.83, OSA with an OR of 1.08 [0.83, 1.39] and hyperlipidemia with an OR of 0.80 [0.61, 1.04]. Combined SG and Roux-en-Y patient cohorts with hyperlipidemia have shown a protective effect of 0.78 [0.65, 0.94].

Conclusions

Significant risk factors for leak post bariatric surgery are smoking in all patients and particularly SG patients, diabetes for all patients and particularly Roux-en-Y patients, and CKD and chronic steroid for all patients. Hyperlipidemia in two combined patient cohorts (SG and Roux-en-Y) appears to have a weak protective effect.