Bariatric surgery, compared to medical treatment, reduces morbidity at all ages but does not reduce mortality in patients aged < 43 years, especially if diabetes mellitus is present: a post hoc analysis of two retrospective cohort studies

Evaluating the Prognostic Value of the Triglyceride-Glucose Index in Different Populations: A Critical Analysis

Background/Objectives: Recent studies have highlighted the Triglyceride-Glucose Index (TYG) as a significant risk factor for mortality and co-morbidities in various populations, including those with type 2 diabetes mellitus (T2DM) and cardiovascular diseases. However, its prognostic role in obese individuals remains less clear. Methods: Utilizing data from an obese cohort of 1359 subjects and from the 1999-2004 cycles of the National Health and Nutrition Examination Survey (NHANES) with 15,267 subjects, this study investigates the prognostic value of TYG and blood glucose in relation to age and sex and other factors such as metabolic syndrome, Charlson Comorbidity Index, T2DM and glucose tolerance, in predicting mortality among obese subjects. Over a median follow-up of about 13 years, 11.3% of the obese cohort and 20.6% of the NHANES cohort died. Our findings indicate that while TYG and blood glucose are significantly related to mortality, they offer only modest improvements over models incorporating age, sex, and other risk factors that showed a prognostic power of 76.1% and 86.0% in the respective cohorts. Conclusions: These results suggest that while TYG holds potential as a prognostic biomarker, its utility beyond established risk factors requires further validation in clinical settings.

The triglyceride-glucose index, blood glucose levels, and metabolic syndrome are associated with all-cause mortality in obesity

BACKGROUND

The Triglyceride-Glucose Index (TYG) has been proposed as a prognostic index for mortality in the general population, in T2DM, and in patients with cardiovascular diseases. However, data on the respective predictive roles of TYG, glucose tolerance (GT), and metabolic syndrome (MS) for mortality in obesity are lacking.

METHODS

We analyzed 1359 obese patients (371 men and 988 women), aged 44.1 ± 12.64 years, followed for 14.3 ± 4.44 years. They were subdivided according to glucose tolerance, in normal glucose tolerance (NGT), impaired fasting glucose (IFG) and type 2 diabetes mellitus (T2DM). We analyzed the risk of death associated with blood glucose (BG) quartiles, TYG quartiles and MS quartiles. Cox proportional-hazard models were used to evaluate the risk of death associated with independent variables that were highly statistically significant at univariate analysis.

RESULTS

Different degrees of glucose tolerance were associated with a progressive deterioration of clinical outcomes, and increased all-cause mortality (6.3 %, 10.1 %, and 20.4 %, respectively). In all groups, age and male sex were associated with increased mortality. Higher TYG or TYG quartiles, BG or BG quartiles, and MS or MS quartiles were all associated with increased all-cause mortality in the whole cohort.

CONCLUSION

TYG, blood glucose and MS are risk factors for mortality in obesity, with a progressively stronger value in IFG and T2DM as compared to NGT.

Alanine transferase levels (ALT) and triglyceride-glucose index are risk factors for type 2 diabetes mellitus in obese patients

AIMS

The role of liver steatosis and increased liver enzymes (ALT) in increasing incident type 2 diabetes mellitus (T2DM) is debated, because of their differential effects on different ethnicities and populations. The aim of this study was to evaluate the role of elevated ALT in the development of T2DM in non-diabetic obese subjects receiving routine medical treatment.

METHODS

A total of 1005 subjects [296 men and 709 women, aged 45.7 ± 13.12 years, body mass index (BMI) 39.5 ± 4.86 kg/m2] were followed for a mean period of 14.3 ± 4.44 years. Subjects were evaluated for several metabolic variables, including the triglyceride-glucose index and the presence of metabolic syndrome (IDF 2005 definition), and were subdivided into ALT quartiles.

RESULTS

T2DM developed in 136 subjects, and the difference was significant between the first and the fourth ALT quartile (p = 0.048). Both at univariate analysis and at stepwise regression, ALT quartiles were associated with incident T2DM. Traditional risk factors for T2DM coexisted, with a somehow greater predictive value, such as triglyceride-glucose index, age, arterial hypertension, LDL-cholesterol, and metabolic syndrome.

CONCLUSIONS

These data suggest an association between elevated ALT levels and the risk of incident T2DM in obesity.

Major Adverse Cardiovascular Events Among Obese Patients with Diabetes After Metabolic and Bariatric Surgery: a Meta-analysis of Matched Cohort and Prospective Controlled Studies with 122,361 Participates

PURPOSE

Metabolic and bariatric surgery (MBS) can exert effective function on glycemic control. The present study aimed to estimate the risk of MACE among obese patients with diabetes after MBS.

MATERIALS AND METHODS

Systematic search of PubMed, Embase, Medline, and Web of Science was performed for studies published before 20th February 2023. The odds ratio (OR) corresponding to the 95% confidence interval (95% CI) was used to assess the outcome. The statistical heterogeneity among studies was assessed with the Q-test and I2 statistics.

RESULTS

Fifteen cohort studies with 122,361 obese patients with diabetes were available for analysis. Our meta-analysis found significantly decreased morbidity and mortality of MACE (OR = 0.65, 95% CI = 0.59-0.72, I2 = 62.8% for morbidity, OR = 0.49, 95% CI = 0.36-0.67, I2 = 68.7% for mortality). Subgroup analysis revealed MBS decreased cerebrovascular disease, coronary artery disease, atrial fibrillation, heart failure, myocardial infarction, and stroke risk.

CONCLUSION

Our meta-analysis indicated that MBS for obese patients with diabetes is beneficial to decreasing MACE risk. Moreover, further studies estimating the functional effect may eventually provide a better and comprehensive understanding of the effect on different populations.

Effect of Prolonged and Substantial Weight Loss on Incident Atrial Fibrillation: A Systematic Review and Meta-Analysis

Background. Overweight and obesity are associated with atrial fibrillation (AF), and bariatric surgery (BS), able to induce sustained and prolonged weight loss, might represent the ideal treatment in the prevention of AF. Previous studies could not definitely establish a role for weight loss and BS in preventing incident AF so far. During the last few years, several studies on the effect of bariatric surgery on cardiovascular diseases have been published, and we performed a systematic review and meta-analysis to evaluate the role of weight loss through BS in the prevention of incident AF in obesity. Methods. This meta-analysis followed the PRISMA guideline. Eligible studies were controlled trials evaluating the appearance of atrial fibrillation in patients undergoing weight loss through BS as compared with patients receiving medical treatment. Quality of studies was assessed according to the Newcastle-Ottawa Quality Assessment Scale, and risk-of-bias was evaluated employing the Egger's test. All analyses were run by a random-effects model according to Hartung and Knapp and sensitivity analyses were performed. Heterogeneity was assessed through Q and I² statistics for each comparison, and potential publication bias was formally investigated. Results. Ten studies were included in the meta-analysis, and the overall result was statistically significant [OR = 0.665 (0.475-0.929), p = 0.017], with significant heterogeneity (Q = 48.98, p < 0.001; I² = 81.6%), but with no publication bias. In sensitivity analyses, the amount of weight loss, percentage of patients with diabetes and value of the Newcastle-Ottawa Quality Assessment Scale, were all associated with significance of effect. Since age was different in one study, a sensitivity analysis was performed by excluding this study; OR was similar [OR = 0.608 (0.454-0.814), p < 0.001]; heterogeneity was reduced but still significant (Q = 35.74, p < 0.001, I² = 77.6%) and again no publication bias was detected. Conclusions. Bariatric surgery as compared to medical treatment is associated with reduced appearance of incident AF.

Risk of Myocardial Infarction, Ischemic Stroke, and Mortality in Patients Who Undergo Gastric Bypass for Obesity Compared With Nonoperated Obese Patients and Population Controls

OBJECTIVE

The aim of this study was to estimate risks of myocardial infarction, ischemic stroke, and cardiovascular-related and all-cause mortality after Roux-en-Y gastric bypass (RYGB) for obesity compared with nonop-erated obese patients and matched nonobese population controls.

BACKGROUND

Few studies have assessed the influence of RYGB on fatal and non-fatal myocardial infarction and ischemic stroke, and the results vary between studies.

METHOD

All patients aged 20 to 65 years with obesity diagnosis in the nationwide Swedish Patient Registry in 2001 to 2013 were included. These participants were divided into those who underwent RYGB within 2 years of obesity diagnosis (n = 28,204) and nonoperated (n = 40,827), and were matched for age, sex, and region with 2 nonobese population controls. Participants were followed until onset of outcome disease, death, or end of follow-up. Multivariable Cox regression provided hazard ratios (HR) with 95% confidence intervals (95% CI).

RESULTS

Compared with nonoperated patients with obesity, RYGB patients had a reduced risk of myocardial infarction [HR = 0.44 (95% CI 0.28-0.63)], similar risk of ischemic stroke [HR = 0.79 (95% CI 0.54-1.14)], and decreased risks of cardiovascular-related [HR = 0.47 (95% CI 0.35-0.65)] and all-cause mortality [HR = 0.66 (95% CI 0.54-0.81)] within the first 3 years of follow-up, but not later. Compared with nonobese population controls, RYGB patients had excess risks of ischemic stroke [HR = 1.57 (95% CI 1.08-2.29)], cardiovascular-related mortality [HR = 1.82 (95% CI 1.29-2.60)], and all-cause mortality [HR = 1.42 (95% CI 1.16-1.74)], but not of myocardial infarction [HR = 1.02 (95% CI 0.72-1.46)].

CONCLUSION

RYGB for obesity might not decrease the risk of ischemic stroke, but seems to decrease the risk of myocardial infarction back to population levels.

OUP accepted manuscript

Aims

Obesity is a global health problem, associated with significant morbidity and mortality, often due to cardiovascular (CV) diseases. While bariatric surgery is increasingly performed in patients with obesity and reduces CV risk factors, its effect on CV disease is not established. We conducted a systematic review and meta-analysis to evaluate the effect of bariatric surgery on CV outcomes, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline.

Methods and results

PubMed and Embase were searched for literature until August 2021 which compared bariatric surgery patients to non-surgical controls. Outcomes of interest were all-cause and CV mortality, atrial fibrillation (AF), heart failure (HF), myocardial infarction, and stroke. We included 39 studies, all prospective or retrospective cohort studies, but randomized outcome trials were not available. Bariatric surgery was associated with a beneficial effect on all-cause mortality [pooled hazard ratio (HR) of 0.55; 95% confidence interval (CI) 0.49–0.62, P < 0.001 vs. controls], and CV mortality (HR 0.59, 95% CI 0.47–0.73, P < 0.001). In addition, bariatric surgery was also associated with a reduced incidence of HF (HR 0.50, 95% CI 0.38–0.66, P < 0.001), myocardial infarction (HR 0.58, 95% CI 0.43–0.76, P < 0.001), and stroke (HR 0.64, 95% CI 0.53–0.77, P < 0.001), while its association with AF was not statistically significant (HR 0.82, 95% CI 0.64–1.06, P = 0.12).

Conclusion

The present systematic review and meta-analysis suggests that bariatric surgery is associated with reduced all-cause and CV mortality, and lowered incidence of several CV diseases in patients with obesity. Bariatric surgery should therefore be considered in these patients.

Effect of Bariatric Surgery on Survival and Hospitalizations in Patients with Severe Obesity. A Retrospective Cohort Study

Bariatric surgery (BS) confers a survival benefit in specific subsets of patients with severe obesity; otherwise, effects on hospital admissions are still uncertain. We assessed the long-term effect on mortality and on hospitalization of BS in patients with severe obesity. This was a retrospective cohort study, including all patients residing in Piedmont (age 18-60 years, BMI ≥ 40 kg/m²) admitted during 2002-2018 to the Istituto Auxologico Italiano. Adjusted hazard ratios (HR) for BS were estimated for mortality and hospitalization, considering surgery as a time-varying variable. Out of 2285 patients, 331 (14.5%) underwent BS; 64.4% received sleeve gastrectomy (SG), 18.7% Roux-en-Y gastric bypass (RYGB), and 16.9% adjustable gastric banding (AGB). After 10-year follow-up, 10 (3%) and 233 (12%) patients from BS and non-BS groups died, respectively (HR = 0.52; 95% CI 0.27-0.98, by a multivariable Cox proportional-hazards regression model). In patients undergoing SG or RYGB, the hospitalization probability decreased significantly in the after-BS group (HR = 0.77; 0.68-0.88 and HR = 0.78; 0.63-0.98, respectively) compared to non-BS group. When comparing hospitalization risk in the BS group only, a marked reduction after surgery was found for all BS types. In conclusion, BS significantly reduced the risk of all-cause mortality and hospitalization after 10-year follow-up.

Association of metabolic-bariatric surgery with long-term survival in adults with and without diabetes: a one-stage meta-analysis of matched cohort and prospective controlled studies with 174 772 participants

BACKGROUND

Metabolic-bariatric surgery delivers substantial weight loss and can induce remission or improvement of obesity-related risks and complications. However, more robust estimates of its effect on long-term mortality and life expectancy-especially stratified by pre-existing diabetes status-are needed to guide policy and facilitate patient counselling. We compared long-term survival outcomes of severely obese patients who received metabolic-bariatric surgery versus usual care.

METHODS

We did a prespecified one-stage meta-analysis using patient-level survival data reconstructed from prospective controlled trials and high-quality matched cohort studies. We searched PubMed, Scopus, and MEDLINE (via Ovid) for randomised trials, prospective controlled studies, and matched cohort studies comparing all-cause mortality after metabolic-bariatric surgery versus non-surgical management of obesity published between inception and Feb 3, 2021. We also searched grey literature by reviewing bibliographies of included studies as well as review articles. Shared-frailty (ie, random-effects) and stratified Cox models were fitted to compare all-cause mortality of adults with obesity who underwent metabolic-bariatric surgery compared with matched controls who received usual care, taking into account clustering of participants at the study level. We also computed numbers needed to treat, and extrapolated life expectancy using Gompertz proportional-hazards modelling. The study protocol is prospectively registered on PROSPERO, number CRD42020218472.

FINDINGS

Among 1470 articles identified, 16 matched cohort studies and one prospective controlled trial were included in the analysis. 7712 deaths occurred during 1·2 million patient-years. In the overall population consisting 174 772 participants, metabolic-bariatric surgery was associated with a reduction in hazard rate of death of 49·2% (95% CI 46·3-51·9, p<0·0001) and median life expectancy was 6·1 years (95% CI 5·2-6·9) longer than usual care. In subgroup analyses, both individuals with (hazard ratio 0·409, 95% CI 0·370-0·453, p<0·0001) or without (0·704, 0·588-0·843, p<0·0001) baseline diabetes who underwent metabolic-bariatric surgery had lower rates of all-cause mortality, but the treatment effect was considerably greater for those with diabetes (between-subgroup I² 95·7%, p<0·0001). Median life expectancy was 9·3 years (95% CI 7·1-11·8) longer for patients with diabetes in the surgery group than the non-surgical group, whereas the life expectancy gain was 5·1 years (2·0-9·3) for patients without diabetes. The numbers needed to treat to prevent one additional death over a 10-year time frame were 8·4 (95% CI 7·8-9·1) for adults with diabetes and 29·8 (21·2-56·8) for those without diabetes. Treatment effects did not appear to differ between gastric bypass, banding, and sleeve gastrectomy (I² 3·4%, p=0·36). By leveraging the results of this meta-analysis and other published data, we estimated that every 1·0% increase in metabolic-bariatric surgery utilisation rates among the global pool of metabolic-bariatric candidates with and without diabetes could yield 5·1 million and 6·6 million potential life-years, respectively.

INTERPRETATION

Among adults with obesity, metabolic-bariatric surgery is associated with substantially lower all-cause mortality rates and longer life expectancy than usual obesity management. Survival benefits are much more pronounced for people with pre-existing diabetes than those without.

FUNDING

None.

Reversal to normal anatomy after one-anastomosis/mini gastric bypass, indications and results: a systematic review and meta-analysis

This review evaluates the indications and outcomes of one-anastomosis/mini gastric bypass (OAGB/MGB) reversal to normal anatomy. A systematic literature search and meta-analysis was performed in PubMed, Web of Science, and Scopus for articles published by October 1, 2020, including the keywords "one anastomosis gastric bypass," "OAGB," "mini gastric bypass," "MGB," "reversal," "reverse," "malnutrition," and "reversal bariatric surgery". After examining 182 papers involving 11,578 patients, 14 studies were included. A reversal was performed in 119 patients on average 23.6 months after the primary OAGB/MGB surgery. The mean body mass index (BMI) was 22.92 ± 3.47 kg/m² and the mean albumin level was 25.17 ± 4.21 g/L at reversal. The mean length of the common channel (CC) was 383.57 ± 159.35 cm, with a mean biliopancreatic limb (BPL) length of 214.21 ± 48.45 cm. Pooled estimation of the meta-analysis of prevalence studies reported a prevalence of 1% for reversal. The major signs and symptoms of protein-energy malnutrition were the leading causes of the reversal of OAGB/MGB. Bleeding, leakage, and death due to severe liver failure were the most reported complications after reversal, with an overall incidence of 10.9%. In conclusion, OAGB/MGB reversal has a prevalence of 1% and has a complication rate of 10.9%. Protein-energy malnutrition with hypoalbuminemia was the most common etiology. The mean lengths of BPL and CC were reported as 215 cm and 380 cm, respectively, in the cases. Therefore, special attention should be paid to malnutrition in all OAGB/MGB patients during follow-up to prevent severe malnutrition and subsequent increase in reversal procedures.

Compared with Controls, Bariatric Surgery Prevents Long-Term Mortality in Persons with Obesity Only Above Median Age of Cohorts: a Systematic Review and Meta-Analysis

PURPOSE

Compared to medical treatment, bariatric surgery reduces long-term mortality in persons with obesity. Some studies indicate that the effect only applies to patients above median age of cohorts, not to younger patients. Our objective was to assess the role of age in the reduction of mortality (global mortality and mortality for specific causes) through bariatric surgery.

MATERIALS AND METHODS

Data sources: PubMed, Cochrane Library, MEDLINE, and Embase.

STUDY SELECTION

studies reporting mortality in relation to median age of patients.

DATA EXTRACTION AND SYNTHESIS

pooled random effects of estimates of the risk of mortality in participants undergoing surgery compared with controls, as function of median age.

RESULTS

Mortality was lower in patients undergoing surgery than in controls (OR = 0.29, 95% CI 0.17-0.49). Below median age, the difference between surgery patients and controls was nonsignificant (OR = 0.78, 95% CI 0.57-1.06). Above median age, the difference was significant (OR = 0.23, 95% CI 0.12-0.44). In a subset of 5 studies, deaths due to various causes were less, and external causes-related deaths were more frequent in surgery than in controls. Below median age, deaths due to CVD were less frequent in surgery than in controls. Above median age, total deaths and deaths due to various causes (cardiovascular, diabetes, cancer, and other causes) were less in surgery than in controls. Publication bias was absent.

CONCLUSION

Compared with controls, bariatric surgery reduces long-term global mortality only above median age, not below median age. Also mortality due to specific causes is mainly reduced in persons above median age.

Type 2 diabetes and metabolic surgery guidelines and recommendations should urgently be unified

Metabolic surgery has been studied in the last decades as an effective and safe treatment for type 2 diabetes (T2D), and randomized controlled trials generally found surgery superior when compared with medical treatment. In 2016, the DSS-II Joint Statement recognized the importance of metabolic surgery in the treatment of T2D and urged clinicians to discuss, recommend, or at least consider this procedure for their patients. Diabetes societies also cogitate metabolic surgery as an option for T2D patients in their guidelines. However, there are some differences in recommendations that could lead a careful reader to some confusion. This was potentialized in a recent document published by the same DSS-II group concerning prioritization for surgery after the COVID-19 pandemic, in which the criteria suggested for an expedited recommendation that is not exactly evidence-based, and collided substantially with several clinical guidelines worldwide, especially with regard to secondary prevention of cardiovascular disease. A more harmonious discussion and unified guidelines between clinicians and surgeons are needed in order to provide the same message for those who read different articles.

Prevention of Diabetes and Cardiovascular Disease in Obesity

Obesity is one of the major risk factors for the development of both impaired glucose tolerance (IGT, or prediabetes) and type 2 diabetes (T2D), and its prevalence worldwide drives toward an increased rate of cardiovascular morbidity and mortality. Given the estimations of the World Health Organization (WHO) and the recommendation of the Diabetes Prevention Program (DPP), where IGT and diabetes are considered as risk factors for the development of cardiovascular complications and obesity, the development of diabetes should be treated because of its potential reversibility. In this view, several interventions such as diet, lifestyle changes, and pharmacological treatment are effective, including bariatric metabolic surgery (BMS), which is the most incisive way to efficiently lower body weight. In this review, we sought to summarize some of the major aspects linked to diabetes prevention in overweight/obesity, focusing on the use of surgery; we also attempted to elucidate molecular pathways involved in a variety of obesity-induced processes able to favor the progression of chronic diseases, such as diabetes and its complications.