Long-term mortality in obese subjects undergoing malabsorptive surgery (biliopancreatic diversion and biliointestinal bypass) versus medical treatment

Bariatric surgery and all-cause mortality: A methodological review of studies using a non-surgical comparator

AIM

Non-randomized studies on bariatric surgery have reported large reductions in mortality within 6-12 months after surgery compared with non-surgical patients. It is unclear whether these findings are the result of bias.

STUDY DESIGN AND SETTING

We searched PubMed to identify all non-randomized studies investigating the effect of bariatric surgery on all-cause mortality compared with non-surgical patients. We assessed these studies for potential confounding and time-related biases. We conducted bias analyses to quantify the effect of these biases.

RESULTS

We identified 21 cohort studies that met our inclusion criteria. Among those, 11 were affected by immortal time bias resulting from the misclassification or exclusion of relevant follow-up time. Five studies were subject to potential confounding bias because of a lack of adjustment for body mass index (BMI). All studies used an inadequate comparator group that lacked indications for bariatric surgery. Bias analyses to correct for potential confounding from BMI shifted the effect estimates towards the null [reported hazard ratio (HR): 0.78 vs. bias-adjusted HR: 0.92]. Bias analyses to correct for the presence of immortal time also shifted the effect estimates towards the null (adjustment for 2-year wait time: reported HR: 0.57 vs. bias-adjusted HR: 0.81).

CONCLUSION

Several important sources of bias were identified in non-randomized studies of the effectiveness of bariatric surgery versus non-surgical comparators on mortality. Future studies should ensure that confounding by BMI is accounted for, considering the choice of the comparator group, and that the design or analysis avoids immortal time bias from the misclassification or exclusion.

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.

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.

Repeated photodynamic therapy using a chlorin e6-embedded device to prolong the therapeutic effects on obesity

OBJECTIVE

This study aimed to investigate the efficacy and safety of repeated photodynamic therapy (PDT) with a chlorin e6 (Ce6)-embedded intragastric satiety-inducing device (ISD) to maintain therapeutic effects of obesity in a juvenile pig.

METHODS

The Ce6-embedded ISD was fabricated with a dipping method. Twelve pigs were divided into four groups of three and were administered control, single, biweekly, or weekly PDT, respectively. The therapeutic effects were assessed by comparing the results of phototoxicity, endoscopy, fluoroscopy, hormone and weight changes, and histological examination.

RESULTS

The percentage of total body weight gain was significantly suppressed in PDT-treated pigs compared with control pigs (all p < 0.001). This suppression persisted in the repeated PDT groups, but percentage of total body weight gain gradually increased when PDT was stopped. Ghrelin levels in the PDT-treated groups were significantly lower and leptin levels were significantly higher than those in the control group (all p < 0.05). Inflammatory cell infiltration, collagen, TUNEL, and anti-ghrelin-positive deposition in the weekly group were significantly higher than those in the control, single, and biweekly groups (all p < 0.01).

CONCLUSIONS

Repeated and periodic PDT was technically feasible and safe and successfully maintained the therapeutic effects against obesity while eliminating the indwelling time and reducing ISD-related complications in pigs.

Clinical Perspectives, Eligibility, and Success Criteria for Bariatric/Metabolic Surgery

Obesity is a worldwide chronic, complex, and progressive disease that poses a challenge for physicians to pursue optimal therapeutic decision making. This chapter focuses on the definition of obesity, based on excessive fat accumulation, and thus underscores the importance of body composition, and the clinical tools used to diagnose it in the context of excess weight, metabolic alteration, and obesity-associated comorbidity development. Additionally, it addresses the indications for surgery that are currently applicable and the description of the different types of patients who could benefit the most from the surgical management of excessive body fat and its associated metabolic derangements and quality of life improvement. Furthermore, it also highlights plausible underlying mechanisms of action for the beneficial effects following bariatric/metabolic surgery.

Clinical outcomes and adverse events of bariatric surgery in adults with severe obesity in Scotland: the SCOTS observational cohort study

Background

Bariatric surgery is a common procedure worldwide for the treatment of severe obesity and associated comorbid conditions but there is a lack of evidence as to medium-term safety and effectiveness outcomes in a United Kingdom setting.

Objective

To establish the clinical outcomes and adverse events of different bariatric surgical procedures, their impact on quality of life and the effect on comorbidities.

Design

Prospective observational cohort study.

Setting

National Health Service secondary care and private practice in Scotland, United Kingdom.

Participants

Adults (age >16 years) undergoing their first bariatric surgery procedure.

Main outcome measures

Change in weight, hospital length of stay, readmission and reoperation rate, mortality, diabetes outcomes (HbA1c, medications), quality of life, anxiety, depression.

Data sources

Patient-reported outcome measures, hospital records, national electronic health records (Scottish Morbidity Record 01, Scottish Care Information Diabetes, National Records Scotland, Prescription Information System).

Results

Between December 2013 and February 2017, 548 eligible patients were approached and 445 participants were enrolled in the study. Of those, 335 had bariatric surgery and 1 withdrew from the study. Mean age was 46.0 (9.2) years, 74.7% were female and the median body mass index was 46.4 (42.4; 52.0) kg/m2. Weight was available for 128 participants at 3 years: mean change was -19.0% (±14.1) from the operation and -24.2% (±12.8) from the start of the preoperative weight-management programme. One hundred and thirty-nine (41.4%) participants were readmitted to hospital in the same or subsequent 35 months post surgery, 18 (5.4% of the operated cohort) had a reoperation or procedure considered to be related to bariatric surgery gastrointestinal complications or revisions. Fewer than five participants (<2%) died during follow-up. HbA1c was available for 93/182 and diabetes medications for 139/182 participants who had type 2 diabetes prior to surgery; HbA1c mean change was -5.72 (±16.71) (p = 0.001) mmol/mol and 65.5% required no diabetes medications (p < 0.001) at 3 years post surgery. Physical quality of life, available for 101/335 participants, improved in the 3 years post surgery, mean change in Rand 12-item Short Form Survey physical component score 8.32 (±8.95) (p < 0.001); however, there was no change in the prevalence of anxiety or depression.

Limitations

Due to low numbers of bariatric surgery procedures in Scotland, recruitment was stopped before achieving the intended 2000 participants and follow-up was reduced from 10 years to 3 years.

Conclusions

Bariatric surgery is a safe and effective treatment for obesity. Patients in Scotland, UK, appear to be older and have higher body mass than international comparators, which may be due to the small number of procedures performed.

Future work

Intervention studies are required to identify the optimal pre- and post surgery pathway to maximise safety and cost-effectiveness.

Study registration

This study is registered as ISRCTN47072588.

Funding details

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 10/42/02) and is published in full in Health Technology Assessment; Vol. 28, No. 7. See the NIHR Funding and Awards website for further award information.

Pyrrhic victory? Long-term results of biliopancreatic diversion on patients with type 2 diabetes and severe obesity

BACKGROUND

The long-term results after biliopancreatic diversion (BPD) in patients with type 2 diabetes (T2D) and severe obesity is still being debated.

OBJECTIVE

Retrospective evaluation of the long-term metabolic and clinical conditions of patients with T2D following BPD.

SETTING

University hospital.

METHODS

A total of 173 patients with T2D and severe obesity were investigated prior to and at 3-5 and 10-20 years after BPD. Anthropometric, biochemical, and clinical findings preoperatively and throughout follow-up were considered. The long-term data were compared with those of a cohort of 173 T2D patients with obesity treated with conventional therapy.

RESULTS

T2D resolved within the first postoperative phases in most patients, and in the long and very long term, the fasting blood glucose level remained above the normal range in only 8% of patients. Likewise, a stable improvement of blood lipid pattern was observed (follow-up rate 63%). In contrast, in nonsurgical patients in the long term, the glucose and lipid metabolic parameters remained in the pathologic range in all cases. In the BPD group, a very high number of severe BPD-related complications was recorded, and 27% of the BPD patients died, whereas in the control group, 87% of patients were still alive at the end of the follow-up period (P < .02).

CONCLUSION

Despite the high T2D stable resolution rate and the normalization of most metabolic data at 10-20 years following surgery, these results indicate that BPD should be indicated with caution in the surgical treatment of T2D in patients with severe obesity.

Metabolic and bariatric surgery and obesity pharmacotherapy for cancer prevention: current status and future possibilities

Obesity is a chronic, relapsing, progressive disease of excess adiposity that increases the risk of developing at least 13 types of cancer. This report provides a concise review of the current state of the science regarding metabolic and bariatric surgery and obesity pharmacotherapy related to cancer risk. Meta-analyses of cohort studies report that metabolic and bariatric surgery is independently associated with a lower risk of incident cancer than nonsurgical obesity care. Less is known regarding the cancer-preventive effects of obesity pharmacotherapy. The recent approval and promising pipeline of obesity drugs will provide the opportunity to understand the potential for obesity therapy to emerge as an evidence-based cancer prevention strategy. There are myriad research opportunities to advance our understanding of how metabolic and bariatric surgery and obesity pharmacotherapy may be used for cancer prevention.

Long-term effects of imaginal retraining in overweight and obesity: A controlled study

BACKGROUND

Imaginal retraining (IR) is a self-help technique that targets automatic approach tendencies toward appetitive stimuli. In a randomized controlled trial (RCT; N = 384), IR reduced craving for high-calorie foods after a six-week intervention period (small effect). The aim of the present study was to evaluate long-term effects of IR in this sample.

METHODS

One year after baseline, participants from the initial RCT were recontacted. A visual analogue scale measuring craving, the Food Cravings Questionnaire-Trait-reduced (FCQ-T-r), the Three-Factor Eating Questionnaire, the Beck Depression Inventory, quality of life, and subjective appraisal of the intervention were assessed online. Participants were classified as users or nonusers based on self-reported usage of IR over the previous year.

RESULTS

Linear-mixed models showed no significant interaction effects of time and group for any outcome (trend level effects were found for two subscales of the FCQ-T-r). Yet, higher usage of IR was associated with greater symptom reduction. Although overall subjective appraisal of the intervention was comparably good to the initial study, usage of IR and completion rate were unsatisfactory.

LIMITATIONS

Main limitations of the present study include the nonrandomized group allocation and the low completion rate.

CONCLUSIONS

This study did not find evidence for the long-term efficacy of IR in individuals with craving for high-calorie foods. Only upon high usage of IR, improvement was found. However, low completion rate and usage of the intervention may have resulted in a Type-II error. Future studies may consider low-intensity professional guidance to increase adherence and assess the long-term effects of IR in RCTs.

Long-term all-cause and cause-specific mortality for four bariatric surgery procedures

OBJECTIVE

This retrospective study incorporated long-term mortality results after different bariatric surgery procedures and for multiple age at surgery groups.

METHODS

Participants with bariatric surgery (surgery) and without (non-surgery) were matched (1:1) for age, sex, BMI, and surgery date with a driver license application/renewal date. Mortality rates were compared by Cox regression, stratified by sex, surgery type, and age at surgery.

RESULTS

Participants included 21,837 matched surgery and non-surgery pairs. Follow-up was up to 40 years (mean [SD], 13.2 [9.5] years). All-cause mortality was 16% lower in surgery compared with non-surgery groups (hazard ratio, 0.84; 95% CI: 0.79-0.90; p < 0.001). Significantly lower mortality after bariatric surgery was observed for both females and males. Mortality after surgery versus non-surgery decreased significantly by 29%, 43%, and 72% for cardiovascular disease, cancer, and diabetes, respectively. The hazard ratio for suicide was 2.4 times higher in surgery compared with non-surgery participants (95% CI: 1.57-3.68; p < 0.001), primarily in participants with ages at surgery between 18 and 34 years.

CONCLUSIONS

Reduced all-cause mortality was durable for multiple decades, for multiple bariatric surgical procedures, for females and males, and for greater than age 34 years at surgery. Rate of death from suicide was significantly higher in surgery versus non-surgery participants only in the youngest age at surgery participants.

The role of bariatric and metabolic surgery in the development, diagnosis, and treatment of endometrial cancer

The obesity pandemic continues to contribute to a worsening burden of disease worldwide. The link between obesity and diseases such as diabetes, cardiovascular disease, and cancer has been well established, yet most patients living with obesity remain untreated or undertreated. Metabolic and bariatric surgery is the most effective and durable treatment for obesity, is safe, and may have a protective benefit with respect to cancer incidence. In this review, an overview of the link between obesity, metabolic surgery, and cancer is discussed with emphasis on indications for endometrial cancer, the malignancy most strongly associated with obesity. Considerable evidence from retrospective and prospective cohort studies supports a decreased risk of endometrial cancer in patients with obesity who undergo bariatric surgery compared with nonsurgical controls. Survivors of endometrial cancer are at increased risk of poor health outcomes associated with obesity, and women with endometrial cancer are more likely to die of cardiovascular disease and other obesity-related illnesses than of the malignancy itself. Recent advances in anticancer drug therapies have targeted pathways that may also be therapeutically altered with metabolic surgery. Metabolic surgery has significant potential to enter the treatment paradigm for endometrial cancer, and gynecologic oncologist visits present an opportunity to identify patients who may benefit the most.

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.

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.

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.

Effects of Bariatric Surgery on Cancer Risk: Evidence from Meta-analysis

INTRODUCTION

Weight loss after bariatric surgery yields important health benefits. A multitude of observational studies have investigated the association of bariatric surgery for severe obesity with the risk of cancer. However, the results were debatable. The aim of the present study was to estimate the effect of bariatric surgery on overall cancer risk.

METHODS

A systematic literature search was performed to identify studies evaluating the association of bariatric surgery for severe obesity with the risk of cancer. Meta-analysis was performed to calculate combined prevalence.

RESULTS

Twenty-one cohort studies with 304,516 patients with obesity having under gone bariatric surgery and 8,492,408 patients with obesity as controls were included. Meta-analysis found decreased cancer risk to be associated with bariatric surgery (OR = 0.56, 95% CI = 0.48-0.66), both for the incidence of cancer (OR = 0.56, 95% CI = 0.46-0.68) and mortality of cancer (OR = 0.56, 95% CI = 0.41-0.75). In subgroup analysis, bariatric surgery was significantly associated with decreased breast cancer risk and endometrial cancer risk, but not associated with other cancer risk.

CONCLUSIONS

Our meta-analysis indicated that bariatric surgery for severe obesity was associated with decreased cancer risk, both for cancer incidence and mortality. Moreover, further studies estimating the functional effect and side effects may eventually provide a better, comprehensive understanding.

Cardiovascular Risk Reduction Following Metabolic and Bariatric Surgery

Cardiovascular disease (CVD) remains a leading cause of morbidity and mortality in developed countries, with worsening pandemics of type 2 diabetes mellitus and obesity as major cardiovascular (CV) risk factors. Clinical trials of nonsurgical obesity treatments have not shown benefits in CVD, although recent diabetes trials have demonstrated major CV benefits. In many retrospective and prospective cohort studies, however, metabolic (bariatric) surgery is associated with substantial and reproducible CVD benefits. Despite a lack of prospective, randomized clinical trials, data suggest metabolic surgery may be the most effective modality for CVD risk reduction, likely through weight loss and weight loss-independent mechanisms.

Metabolic surgery: A clinical update

Metabolic and bariatric surgery has grown beyond 'experimental' weight-loss surgery. As techniques have advanced over the last few decades, so has the growing body of research and evidence, proving that both weight-loss and metabolic health improvement are induced. Metabolic surgery has become the more appropriate term for weight-loss surgery because of the altered gastrointestinal anatomy and subsequent beneficial metabolic effects. Although the tool of metabolic surgery has been well refined, a large portion of the global population does not have adequate access to it. This clinical update aims to (a) inform healthcare providers from all disciplines about the myriad of benefits of metabolic surgery and (b) equip them with the necessary knowledge to bridge the gap between patients in need of metabolic treatment and the therapies in metabolic surgery available to them.

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.

Association of bariatric surgery with all-cause mortality and incidence of obesity-related disease at a population level: A systematic review and meta-analysis

BACKGROUND

Previous clinical trials and institutional studies have demonstrated that surgery for the treatment of obesity (termed bariatric or metabolic surgery) reduces all-cause mortality and the development of obesity-related diseases such as type 2 diabetes mellitus (T2DM), hypertension, and dyslipidaemia. The current study analysed large-scale population studies to assess the association of bariatric surgery with long-term mortality and incidence of new-onset obesity-related disease at a national level.

METHODS AND FINDINGS

A systematic literature search of Medline (via PubMed), Embase, and Web of Science was performed. Articles were included if they were national or regional administrative database cohort studies reporting comparative risk of long-term mortality or incident obesity-related diseases for patients who have undergone any form of bariatric surgery compared with an appropriate control group with a minimum follow-up period of 18 months. Meta-analysis of hazard ratios (HRs) was performed for mortality risk, and pooled odds ratios (PORs) were calculated for discrete variables relating to incident disease. Eighteen studies were identified as suitable for inclusion. There were 1,539,904 patients included in the analysis, with 269,818 receiving bariatric surgery and 1,270,086 control patients. Bariatric surgery was associated with a reduced rate of all-cause mortality (POR 0.62, 95% CI 0.55 to 0.69, p < 0.001) and cardiovascular mortality (POR 0.50, 95% CI 0.35 to 0.71, p < 0.001). Bariatric surgery was strongly associated with reduced incidence of T2DM (POR 0.39, 95% CI 0.18 to 0.83, p = 0.010), hypertension (POR 0.36, 95% CI 0.32 to 0.40, p < 0.001), dyslipidaemia (POR 0.33, 95% CI 0.14 to 0.80, p = 0.010), and ischemic heart disease (POR 0.46, 95% CI 0.29 to 0.73, p = 0.001). Limitations of the study include that it was not possible to account for unmeasured variables, which may not have been equally distributed between patient groups given the non-randomised design of the studies included. There was also heterogeneity between studies in the nature of the control group utilised, and potential adverse outcomes related to bariatric surgery were not specifically examined due to a lack of available data.

CONCLUSIONS

This pooled analysis suggests that bariatric surgery is associated with reduced long-term all-cause mortality and incidence of obesity-related disease in patients with obesity for the whole operated population. The results suggest that broader access to bariatric surgery for people with obesity may reduce the long-term sequelae of this disease and provide population-level benefits.

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

BACKGROUND AND AIMS

Bariatric surgery (BS) reduces long-term mortality in comparison with medical treatment of obesity. Some studies indicate that this effect is significant for patients above mean age in different cohorts, but not for younger patients. These findings raise the question whether morbid obese patients should undergo BS as soon as possible, or whether patients might undergo surgery later in their life.

METHODS

We performed a post hoc analysis of two studies; we evaluated surgery-related long-term mortality in: (1) the whole cohort [857 surgery patients (163 diabetes) vs. 2086 controls (512 diabetes)]; (2) patients above mean age [> 43 years, 427 surgery patients (133 diabetes) vs. 1054 controls (392 diabetes)]; (3) patients below mean age [≤ 43 years, 432 surgery patients (30 diabetes) vs. 1032 controls (120 diabetes]. Then, we analyzed age-related long-term mortality in the whole cohort, as well as in surgery patients and in controls. Finally, we analyzed incident diseases (diabetes, cardiovascular disease, and cancer) as a function of surgery versus no-surgery and of mean age.

RESULTS

Surgery patients, compared with controls receiving standard medical/dietary treatment, had reduced mortality in the whole cohort (HR = 0.45, 95% CI 0.33-0.62, p = 0.001) and in the study group aged > 43 years (HR = 0.39, 95% CI 0.28-0.56, p = 0.001), but not in the study group aged ≤ 43 years (HR = 0.87, 95% CI 0.42-1.80, p = 0.711). Reduced mortality was observed in non-diabetic and diabetic patients aged > 43 years (HR = 0.37, 95% CI 0.23-0.62, p = 0.001 and HR = 0.45, 95% CI 0.27-0.74, p = 0.002, respectively) who underwent bariatric surgery. In contrast, in patients aged ≤ 43 years, no significant protective effect of bariatric surgery appeared in non-diabetic patients (HR = 0.64, 95% CI 0.24-1.71, p = 0.371), and mortality increased, almost significantly, in diabetic patients aged < 43 years (HR = 2.87, 95% CI 0.96-8.56, p = 0.058), and even more in diabetic patients aged 33-43 years; HR = 4.99, 95% CI 1.18-21.09, p = 0.029). As expected, age-related mortality was increased in the whole cohort (HR = 7.23, 95% CI 5.14-10.17, p = 0.001), in non-diabetic and diabetic controls (HR = 8.55, 95% CI 5.77-12.68, p = 0.001, and HR = 3.76, 95% CI 1.97-7.18, p = 0.001, respectively). The effect of aging was slightly reduced in surgery patients (HR = 3.76, 95% CI 1.87-7.58, p = 0.001), while it was not significant in diabetic surgery patients (HR = 0.70, 95% CI 0.26-1.90, p = 0.88), further emphasizing that diabetes per se has a strong negative effect on survival, also with concomitant bariatric surgery. In a supplementary analysis, HRs did not change when surgery and control parents were matched for the presence of diabetes. Incident diseases (cardiovascular, diabetes, and cancer) were less frequent in surgery than in control patients, irrespective of age.

CONCLUSION

Bariatric surgery reduces long-term mortality in comparison with medical treatment when performed in patients aged > 43 years, but not in younger patients, where it is neutral or could even increase mortality; reduction in morbidity occurs at any age.

A 23-year study of mortality and development of co-morbidities in patients with obesity undergoing bariatric surgery (laparoscopic gastric banding) in comparison with medical treatment of obesity

Background and aim

Several studies have shown that bariatric surgery reduces long term mortality compared to medical weight loss therapy. In a previous study we have demonstrated that gastric banding (LAGB) is associated with reduced mortality in patients with and without diabetes, and with reduced incidence of obesity co-morbidities (cardiovascular disease, diabetes, and cancer) at a 17 year follow-up. The aim of this study was to verify at a longer time interval (23 years) mortality and incidence of co-morbidities in patients undergoing LAGB or medical weight loss therapy.

Patients and methods

As reported in the previous shorter-time study, medical records of obese patients [body mass index (BMI) > 35 kg/m² undergoing LAGB (n = 385; 52 with diabetes) or medical treatment (controls, n = 681; 127 with diabetes), during the period 1995–2001 (visit 1)] were collected. Patients were matched for age, sex, BMI, and blood pressure. Identification codes of patients were entered in the Italian National Health System Lumbardy database, that contains life status, causes of death, as well as exemptions, prescriptions, and hospital admissions (proxies of diseases) from visit 1 to June 2018. Survival was compared across LAGB patients and matched controls using Kaplan–Meier plots adjusted Cox regression analyses.

Results

Final observation period was 19.5 ± 1.87 years (13.4–23.5). Compared to controls, LAGB was associated with reduced mortality [HR = 0.52, 95% CI 0.33–0.80, p = 0.003], significant in patients with diabetes [HR = 0.46, 95% CI 0.22–0.94, p = 0.034], borderline significant in patients without diabetes [HR = 0.61, 95% CI = 0.35–1.05, p = 0.076]. LAGB was associated with lower incidence of diabetes (15 vs 75 cases, p = 0.001), of CV diseases (61 vs 226 cases, p = 0.009), of cancer (10 vs 35, p = 0.01), and of renal diseases (0 vs 35, p = 0.001), and of hospital admissions (92 vs 377, p = 0.001).

Conclusion

The preventive effect of LAGB on mortality is maintained up to 23 years, even with a decreased efficacy compared with the shorter-time study, while the preventive effect of LAGB on co-morbidities and on hospital admissions increases with time.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0801-1) contains supplementary material, which is available to authorized users.