Revisiting the Role of BMI in the Guidelines for Bariatric Surgery

Body mass index and benign breast surgeries: a survey of plastic surgeons’ knowledge and attitudes

Background

The academic literature has not arrived at a consensus on the importance of body mass index (BMI) as an indicator of surgical feasibility and risk. This study evaluates board-certified plastic surgeons' and trainees' knowledge, experiences, and concerns around performing benign breast surgeries in high-BMI patients.

Methods

An online survey instrument was developed and shared with plastic surgeons and plastic surgery trainees from December 2021 to January 2022.

Results

There were 30 respondents (18 from Israel, 11 from the United States, and 1 from Turkey). For respondents who had BMI guidelines for performing benign breast surgeries, the median maximum BMI was 35 for all procedures. Most respondents supported or strongly supported their BMI guidelines.The majority of respondents indicated that they tended to have less training and experience in performing benign breast surgeries on high-BMI patients compared to those with BMI <30. Most respondents indicated that they were less satisfied with the results of these procedures on high-BMI patients compared to those with BMI <30. The median post-operation recovery time was indicated to be similar for high-BMI patients compared to those with BMI <30 across all procedures; however, the postoperative complication rate was indicated as higher.

Conclusions

Respondents indicated that the risks of complication, more frequent need for surgical revisions, and unsatisfactory outcomes were their greatest concerns when conducting chest surgeries among high-BMI patients. Given that most surgeons practice in settings where high-BMI patients are excluded from procedure access, further research is needed to assess the extent to which these concerns reflect actual outcome differences.

The Impact of Bariatric Surgery on the Muscle Mass in Patients with Obesity: 2-Year Follow-up

PURPOSE

Bariatric surgery (BS) induces a significant and sustained weight loss in patients with severe obesity (SO). Nevertheless, apart from significantly reducing body fat, fat-free mass (FFM) might also be lost. At present, there is little and controversial data in the literature regarding the impact of BS on FFM. In recent years, bioimpedance (BIA) has emerged as a reliable test to assess body composition easily to use in the daily clinical practice. On the bases, the aim of the present study is to evaluate the impact of BS on the FFM, evaluated by means of BIA.

MATERIAL AND METHODS

This is a prospective, observational study, including consecutive patients with SO that underwent BS between February 2018 and February 2019 at our center. At baseline, 1, 6, 12, and 24 months after the BS, all the patients underwent complete medical history, physical and anthropometric evaluation, and body composition assessment by means of BIA (using Bodystat QuadScan4000®).

RESULTS

Eighty-five patients with SO were recruited, 72.9% females, aged 45.54 ± 9.98 years, pre-BS BMI 43.87 ± 6.52 kg/m2. FFM significantly decreased continuously after BS at all timepoints. The loss of FFM 24 months post-BS accounted for approximately 21.71 ± 13.9% of the total weight loss, and was independent of BS technique or protein metabolism. Pre-BS HOMA-IR and FFM were independent predictors of FFM at 24 months.

CONCLUSIONS

Significant and early loss of FFM in patients with SO that undergo BS was seen, not related to protein metabolism parameters or the BS technique used, suggesting an independent mechanism.

Clinical Use of the Edmonton Obesity Staging System for the Assessment of Weight Management Outcomes in People with Class 3 Obesity

We aimed to assess weight loss and metabolic outcomes by severity of weight-related complications following an intensive non-surgical weight management program (WMP) in an Australian public hospital. A retrospective cohort study of all patients aged ≥18 years with body mass index (BMI) ≥ 40 enrolled in the WMP during March 2018−March 2019 with 12-month follow-up information were stratified using the Edmonton Obesity Staging System (EOSS). Of 178 patients enrolled in the WMP, 112 (62.9%) completed at least 12 months’ treatment. Most patients (96.6%) met EOSS-2 (56.7%) or EOSS-3 (39.9%) criteria for analysis. Both groups lost significant weight from baseline to 12 months; EOSS-2: 139.4 ± 31.8 kg vs. 131.8 ± 31.8 kg (p < 0.001) and EOSS-3: 141.4 ± 24.2 kg vs. 129.8 ± 24.3 kg (p < 0.001). After adjusting for baseline age, sex and employment status, mean weight loss was similar but a greater proportion of EOSS-3 achieved >10% weight loss compared to EOSS-2, (40% vs. 15.9%, p = 0.024). Changes in metabolic parameters including HbA1c, BP and lipids did not differ between EOSS-2 and 3. Despite increased clinical severity, adult patients with class 3 obesity achieved clinically meaningful weight loss and similar improvements in metabolic parameters compared to patients with less severe complications after 12 months in an intensive non-surgical WMP.

Nutritional Management in Bariatric Surgery Patients

The obesity epidemic, mainly due to lifestyle changes in recent decades, leads to serious comorbidities that reduce life expectancy. This situation is affecting the health policies of many nations around the world. Traditional measures such as diet, physical activity, and drugs are often not enough to achieve weight loss goals and to maintain the results over time. Bariatric surgery (BS) includes various techniques, which favor rapid and sustained weight loss. BS is a useful and, in most cases, the best treatment in severe and complicated obesity. In addition, it has a greater benefit/risk ratio than non-surgical traditional therapies. BS can allow the obese patient to lose weight quickly compared with traditional lifestyle changes, and with a greater probability of maintaining the results. Moreover, BS promotes improvements in metabolic parameters, even diabetes remission, and in the quality of life. These changes can lead to an increase of life expectancy by over 6 years on average. The nutrition of people before and after BS must be the subject of indications from a trained staff, and patients must be followed in the subsequent years to reduce the risk of malnutrition and the associated problems. In particular, it is still debated whether it is necessary to lose weight prior to surgery, a procedure that can facilitate the surgeon's work reducing the surgical risk, but at the same time, lengthens preparation times increasing the risks associated with concomitant pathologies. Furthermore, preventing nutritional deficiencies prior to the intervention can improve the results and reduce short- and long-term mortality.

Prognostic Models for Predicting Remission of Diabetes Following Bariatric Surgery: A Systematic Review and Meta-analysis

BACKGROUND

Remission of type 2 diabetes following bariatric surgery is well established, but identifying patients who will go into remission is challenging.

PURPOSE

To perform a systematic review of currently available diabetes remission prediction models, compare their performance, and evaluate their applicability in clinical settings.

DATA SOURCES

A comprehensive systematic literature search of MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) was undertaken. The search was restricted to studies published in the last 15 years and in the English language.

STUDY SELECTION

All studies developing or validating a prediction model for diabetes remission in adults after bariatric surgery were included.

DATA EXTRACTION

The search identified 4,165 references, of which 38 were included for data extraction. We identified 16 model development and 22 validation studies.

DATA SYNTHESIS

Of the 16 model development studies, 11 developed scoring systems and 5 proposed logistic regression models. In model development studies, 10 models showed excellent discrimination with area under the receiver operating characteristic curve ≥0.800. Two of these prediction models, ABCD and DiaRem, were widely externally validated in different populations, in a variety of bariatric procedures, and for both short- and long-term diabetes remission. Newer prediction models showed excellent discrimination in test studies, but external validation was limited.

LIMITATIONS

While the key messages were consistent, a large proportion of the studies were conducted in small cohorts of patients with short duration of follow-up.

CONCLUSIONS

Among the prediction models identified, the ABCD and DiaRem models were the most widely validated and showed acceptable to excellent discrimination. More studies validating newer models and focusing on long-term diabetes remission are needed.

Time Course of Metabolic, Neuroendocrine, and Adipose Effects During 2 Years of Follow-up After Gastric Bypass in Patients With Type 2 Diabetes

CONTEXT

Roux-en-Y gastric bypass surgery (RYGB) markedly improves glycemia in patients with type 2 diabetes (T2D), but underlying mechanisms and changes over time are incompletely understood.

OBJECTIVE

Integrated assessment of neuroendocrine and metabolic changes over time in T2D patients undergoing RYGB.

DESIGN AND SETTING

Follow-up of single-center randomized study.

PATIENTS

Thirteen patients with obesity and T2D compared to 22 healthy subjects.

INTERVENTIONS

Blood chemistry, adipose biopsies, and heart rate variability were obtained before and 4, 24, and 104 weeks post-RYGB.

RESULTS

After RYGB, glucose-lowering drugs were discontinued and hemoglobin A1c fell from mean 55 to 41 mmol/mol by 104 weeks (P < 0.001). At 4 weeks, morning cortisol (P < 0.05) and adrenocorticotropin (P = 0.09) were reduced by 20%. Parasympathetic nerve activity (heart rate variability derived) increased at 4 weeks (P < 0.05) and peaked at 24 weeks (P < 0.01). C-reactive protein (CRP) and white blood cells were rapidly reduced (P < 0.01). At 104 weeks, basal and insulin-stimulated adipocyte glucose uptake increased by 3-fold vs baseline and expression of genes involved in glucose transport, fatty acid oxidation, and adipogenesis was upregulated (P < 0.01). Adipocyte volume was reduced by 4 weeks and more markedly at 104 weeks, by about 40% vs baseline (P < 0.01).

CONCLUSIONS

We propose this order of events: (1) rapid glucose lowering (days); (2) attenuated cortisol axis activity and inflammation and increased parasympathetic tone (weeks); and (3) body fat and weight loss, increased adipose glucose uptake, and whole-body insulin sensitivity (months-years; similar to healthy controls). Thus, neuroendocrine pathways can partly mediate early glycemic improvement after RYGB, and adipose factors may promote long-term insulin sensitivity and normoglycemia.

Usefulness of the Edmonton Obesity Staging System for stratifying the presence and severity of weight-related health problems in clinical and community settings: A rapid review of observational studies

This rapid review aimed to examine the usefulness of the Edmonton Obesity Staging System (EOSS) for stratifying the presence and severity of weight-related health problems in clinical and community settings. We searched PubMed, CINAHL and ProQuest for records from 2009 to May 2020. We considered observational studies in participants with overweight or obesity that investigated the risk of any clinical outcome associated with increasing EOSS. We reviewed and appraised 20 observational studies (cohort = 4, case series = 7, cross-sectional = 9) published between 2011 and 2020. Of 12 studies in clinical populations, the EOSS was most consistently associated with an increased risk of postoperative complications following bariatric surgery, especially for EOSS 3-4, and inversely associated with weight loss, treatment time and resolution of hypertension following bariatric surgery and clinical weight management. Of eight studies in community populations, the EOSS most consistently predicted mortality outcomes, especially for EOSS 3, and was associated with polypharmacy, service use and poorer work outcomes. Studies reported diverse EOSS definitions and outcomes, which slightly weakens the overall evidence base. The EOSS should be routinely used for predicting risks and benefits of surgical and nonsurgical weight management, but it should be applied with caution for population health planning.

Association between metabolic surgery and cardiovascular outcome in patients with hypertension: A nationwide matched cohort study

BACKGROUND

Hypertension, together with obesity, is a leading cause of mortality and disability. Whilst metabolic surgery offers remission of several metabolic comorbidities, the effect for patients with hypertension remains controversial. The objective of the present study was to evaluate the effect of metabolic surgery on cardiovascular events and mortality on patients with morbid obesity (body mass index [BMI] ≥ 35 kg/m2) and hypertension.

METHODS AND FINDINGS

We conducted a matched cohort study of 11,863 patients with morbid obesity and pharmacologically treated hypertension operated on with metabolic surgery and a matched non-operated-on control group of 26,199 subjects with hypertension (matched by age, sex, and area of residence) of varied matching ratios from 1:1 to 1:9, using data from the Scandinavian Obesity Surgery Register (SOReg), the Swedish National Patient Registers (NPR) for in-hospital and outpatient care, the Swedish Prescribed Drug Register, and Statistics Sweden. The main outcome was major adverse cardiovascular event (MACE), defined as first occurrence of acute coronary syndrome (ACS) event, cerebrovascular event, fatal cardiovascular event, or unattended sudden cardiac death. The mean age in the study group was 52.1 ± 7.46 years, with 65.8% being women (n = 7,810), and mean BMI was 41.9 ± 5.43 kg/m2. MACEs occurred in 379 operated-on patients (3.2%) and 1,125 subjects in the control group (4.5%). After adjustment for duration of hypertension, comorbidities, and education, a reduction in risk was seen in the metabolic surgery group (adjusted hazard ratio [HR] 0.73, 95% confidence intervals [CIs] 0.64-0.84, P < 0.001). The surgery group had lower risk for ACS events (adjusted HR 0.52, 95% CI 0.41-0.66, P < 0.001) and a tendency towards lower risk for cerebrovascular events (adjusted HR 0.81, 95% CI 0.63-1.01, P = 0.060) compared with controls. The main limitations with the study were the lack of information on BMI and history of smoking in the control group and the nonrandomised study design.

CONCLUSION

Metabolic surgery on patients with morbid obesity and pharmacologically treated hypertension was associated with lower risk for MACEs and all-cause mortality compared with age- and sex-matched controls with hypertension from the general population.

Sleeve gastrectomy enhances glucose utilization and remodels adipose tissue independent of weight loss

Sleeve gastrectomy (SG) induces weight loss-independent improvements in glucose homeostasis by unknown mechanisms. We sought to identify the metabolic adaptations responsible for these improvements. Nonobese C57BL/6J mice on standard chow underwent SG or sham surgery. Functional testing and indirect calorimetry were used to capture metabolic phenotypes. Tissue-specific glucose uptake was assessed by 18-fluorodeoxyglucose (18-FDG) PET/computed tomography, and RNA sequencing was used for gene-expression analysis. In this model, SG induced durable improvements in glucose tolerance in the absence of changes in weight, body composition, or food intake. Indirect calorimetry revealed that SG increased the average respiratory exchange ratio toward 1.0, indicating a weight-independent, systemic shift to carbohydrate utilization. Following SG, orally administered 18-FDG preferentially localized to white adipose depots, showing tissue-specific increases in glucose utilization induced by surgery. Transcriptional analysis with RNA sequencing demonstrated that increased glucose uptake in the visceral adipose tissue was associated with upregulation in transcriptional pathways involved in energy metabolism, adipocyte maturation, and adaptive and innate immune cell chemotaxis and differentiation. SG induces a rapid, weight loss-independent shift toward glucose utilization and transcriptional remodeling of metabolic and immune pathways in visceral adipose tissue. Continued study of this early post-SG physiology may lead to a better understanding of the anti-diabetic mechanisms of bariatric surgery.

Remission of Type 2 Diabetes Mellitus after Bariatric Surgery: Fact or Fiction?

Although type 2 diabetes mellitus (T2DM) has been traditionally viewed as an intractable chronic medical condition, accumulating evidence points towards the notion that a complete remission of T2DM is feasible following a choice of medical and/or surgical interventions. This has been paralleled by increasing interest in the establishment of a universal definition for T2DM remission which, under given circumstances, could be considered equivalent to a “cure”. The efficacy of bariatric surgery in particular for achieving glycemic control has highlighted surgery as a candidate curative intervention for T2DM. Herein, available evidence regarding available surgical modalities and the mechanisms that drive metabolic amelioration after bariatric surgery are reviewed. Furthermore, reports from observational and randomized studies with regard to T2DM remission are reviewed, along with concepts relevant to the variety of definitions used for T2DM remission and other potential sources of discrepancy in success rates among different studies.

Bariatric Surgery to Reduce Mortality in US Adults. A Public Health Perspective from the Analysis of the American National Health and Nutrition Examination Survey Linked to the US Mortality Register

BACKGROUND

Type II obesity represents a major pandemic and public health threat in high-income countries. Type II obesity increases the risk of all-cause and specific-cause mortality, and it is widely acknowledged that bariatric surgery represents the only effective therapeutic option in these patients. The aim of the present study was to estimate US population attributable risk for all-cause and cause-specific mortality in type II obese subjects undergoing weight loss as resulting from bariatric surgery alone and supplemented with behavioral intervention.

METHODS

The American National Health and Nutrition Examination Survey linked to the US death registry updated to 2011 was used to estimate type II obesity prevalence and all-cause and specific cause of death for type II obese adults undergoing weight loss. Multivariate adjusted proportional hazard Cox models were used to estimate mortality risks. Statistical analyses were performed on the most updated version of the database (June 2017).

RESULTS

A monotone positive trend for type II obesity was observed during the period 1999-2014 (p < 0.001). According to trend analysis, the rate of type II obesity in US adults is expected to rise up to 8.5%. Two- to sevenfold increased risk of all-cause and specific-cause mortality was observed for type II obese participants when compared to type I obese and overweight participants. Population attributable risk for all-cause and specific-cause mortality for type II obese subjects undergoing weight loss was ranging between 6 and 34%.

CONCLUSIONS

Bariatric surgery supplemented with behavioral intervention can result in a relevant reduction of mortality if extensively applied to the US population.