Preoperative weight loss is not a predictor of postoperative weight loss after laparoscopic Roux-en-Y gastric bypass

Variation in pre-operative insurance requirements for bariatric surgery

BACKGROUND

For patients who wish to undergo bariatric surgery, variation in pre-operative insurance requirements may represent inequity across insurance plan types. We conducted a cross-sectional assessment of the variation in pre-operative insurance requirements.

METHODS

Original insurance policy documents for pre-operative requirements were obtained from bariatric surgery programs across the entire USA and online insurance portals. Insurance programs analyzed include commercial, Medicaid, and Medicare/TriCare plans. Poisson regression adjusting for U.S. Census region was used to evaluate variation in pre-operative requirements. Analyses were done at the insurance plan level. Our primary outcome was number of requirements required by each plan by insurance type. Our secondary outcome was number of months required to participate in medically supervised weight loss (MSWL).

RESULTS

Among 43 insurance plans reviewed, representing commercial (60.5%), Medicaid (25.6%), and Medicare/TriCare (14.0%) plans, the number of pre-operative requirements ranged from 1 to 8. Adjusted Poisson regression showed significant variation in pre-operative requirements across plan types with Medicaid-insured patients required to fulfill the greatest number (4.1, 95%CI 2.7 to 5.4) compared to 2.7 (95%CI 2.2 to 3.2, P = 0.028) for commercially insured patients and 2.1 (95%CI 1.1 to 3.1, P = 0.047) for Medicare/TriCare-insured patients. Medicaid-insured patients were also required to complete a greater number of months in MSWL (6.6, 95%CI 5.5 to 7.6) compared to commercially (3.8, 95%CI 2.9 to 4.8, P < .001) and Medicare/TriCare-insured patients (1.7, 95%CI 0.3 to 3.0, P = .001).

CONCLUSION

The greater frequency of pre-operative requirements in Medicaid plans compared to Medicare/TriCare and commercial plans demonstrates inequity across insurance types which may negatively impact access to bariatric surgery. Pre-operative insurance requirements must be reevaluated and standardized using established evidence to ensure all individuals have access to this life-saving intervention.

Preoperative Weight Loss as a Predictor of Bariatric Surgery Postoperative Weight Loss and Complications

BACKGROUND

The association between preoperative weight loss and bariatric surgery outcomes remains unclear. We explored the utility of preoperative weight loss as a predictor of postoperative weight loss success. Additionally, we examined the association of preoperative weight loss with perioperative complication rates.

METHODS

Retrospective chart review of patients who underwent primary sleeve gastrectomy or primary Roux-en-Y gastric bypass for weight loss at a single institution between January 2003 and November 2017. Additional follow-up was obtained by a postoperative standardized patient questionnaire. Statistical analysis consisted of bivariate and multivariate logistic regression analysis.

RESULTS

Our study included 427 patients. Majority were female (n = 313, 73.3%) and underwent sleeve gastrectomy (n = 261, 61.1%). Average age was 45.6 years, and average follow-up was 6.3 years. Greater preoperative weight loss was associated with decreased length of stay (1.8 vs 1.3 days) in patients who underwent sleeve gastrectomy. Multivariable regression analysis revealed that preoperative weight loss was not associated with postoperative weight loss.

CONCLUSIONS

Preoperative weight loss is not predictive of postoperative weight loss success after bariatric surgery. Greater preoperative weight loss was associated with a mild decreased in length of stay but was not associated with a reduction in operative time, overall complication rates, ICU admissions, or intraoperative complications. The inconclusive literature and our findings do not support the medical necessity of weight loss prior to bariatric surgery for the purpose of reducing surgical complications or predicting successful postoperative weight loss success.

Development and validation of a scoring system for pre-surgical and early post-surgical prediction of bariatric surgery unsuccess at 2 years

Bariatric surgery (BS) is an effective treatment for morbid obesity. However, a simple and easy-to-use tool for the prediction of BS unsuccess is still lacking. Baseline and follow-up data from 300 consecutive patients who underwent BS were retrospectively collected. Supervised regression and machine-learning techniques were used for model development, in which BS unsuccess at 2 years was defined as a percentage of excess-weight-loss (%EWL) < 50%. Model performances were also assessed considering the percentage of total-weight-loss (%TWL) as the reference parameter. Two scoring systems (NAG-score and ENAG-score) were developed. NAG-score, comprising only pre-surgical data, was structured on a 4.5-point-scale (2 points for neck circumference ≥ 44 cm, 1.5 for age ≥ 50 years, and 1 for fasting glucose ≥ 118 mg/dL). ENAG-score, including also early post-operative data, was structured on a 7-point-scale (3 points for %EWL at 6 months ≤ 45%, 1.5 for neck circumference ≥ 44 cm, 1 for age ≥ 50 years, and 1.5 for fasting glucose ≥ 118 mg/dL). A 3-class-clustering was proposed for clinical application. In conclusion, our study proposed two scoring systems for pre-surgical and early post-surgical prediction of 2-year BS weight-loss, which may be useful to guide the pre-operative assessment, the appropriate balance of patients' expectations, and the post-operative care.

Systematic Review and Meta-Analysis of the Effectiveness of Insurance Requirements for Supervised Weight Loss Prior to Bariatric Surgery

Many insurance plans impose strict criteria mandating preoperative weight loss attempts to limit patient's access to surgery. Preoperative acute weight loss has been hypothesized to reduce perioperative risk and to identify compliant patients who may have improved long-term weight loss. In this review, the evidence from studies examining clinical and weight loss outcomes both with and without preoperative weight loss are summarized. Although preoperative weight loss may have modest impact on some factors related to perioperative conduct, the evidence does not support these programs' effectiveness at promoting long-term weight loss. Provision of weight loss surgery should not be contingent on completion of insurance-mandated weight loss goals preoperatively, and these programs may, through patient attrition, actually do more harm than good.

Racial disparities in bariatric surgery postoperative weight loss and co-morbidity resolution: a systematic review

While bariatric surgery is an accepted treatment for morbid obesity, the impact of race on surgical outcomes remains unclear. This systematic review aims to compare differences in weight loss and co-morbidity outcomes among various races after bariatric surgery. PubMed, Medline, and SCOPUS databases were queried to identify publications that included more than 1 racial group and reported weight loss outcomes after bariatric surgery. A total of 52 studies were included. Non-Hispanic black (NHB) patients comprised between 5.5% and 69.7% and Hispanic patients comprised between 4.7% and 65.3% of the studies' populations. Definitions of weight loss success differed widely across studies, with percent excess weight loss being the most commonly reported outcome, followed by percent total weight loss and change in body mass index (BMI). Statistical analyses also varied, with most studies adjusting for age, sex, preoperative weight, or BMI. Some studies also adjusted for preoperative co-morbidities, including diabetes mellitus, hypertension, and hyperlipidemia, or socioeconomic status, including income, education, and neighborhood poverty. The majority of studies found less favorable weight loss in NHB compared to Hispanic and non-Hispanic white (NHW), patients while generally no difference was found between Hispanic and NHW patients. The trend also indicates no association between race and resolution of obesity-related co-morbidities. Racial minorities lose less weight than NHW patients after bariatric surgery, although the factors associated with this discrepancy are unclear. The heterogeneity in reporting weight loss success and statistical analyses amongst the literature makes an estimation of effect size difficult. Generally, racial disparity was not seen when examining co-morbidity resolution after surgery. More prospective, robust, long-term studies are needed to understand the impacts of race on bariatric surgery outcomes and ensure successful outcomes for all patients, regardless of race.

Preoperative weight loss in women with obesity in gynaecologic oncology: A retrospective study

To retrospectively review the efficacy of short term supervised medical weight loss for women with obesity, body mass index (BMI ≥40 kg/m² ) in gynaecologic oncology, and the associated perioperative and pathologic outcomes. A retrospective study of a dedicated preoperative weight loss clinic for gynaecologic oncology patients from March to December 2019. Statistical analysis was performed with McNemar's test for correlated proportions, Pearson's correlation tests for continuous variables, and paired t-tests to compare means. Generalized estimating equations (GEE) were used to determine the factors associated with weight loss over time. A P-value of <.05 was used for statistical significance. Review of cases up-graded after surgery was performed by a gynaecologic pathologist. There were a total of 49 women included in the study. The most common referral reason was endometrioid carcinoma or hyperplasia of the endometrium (77.6%). Mean initial weight was 130.2 kg, and corresponding mean BMI 48.1 kg/m² . Patients attended on average nine preoperative weight loss visits. A significant difference between initial weight and weight at surgery was demonstrated, from 129.6 to 118.0 kg (8.4% weight loss) (P < .0001). This difference persisted to their post-surgical visit, with an additional mean loss of 1.89 kg (9.4% weight loss) (P = .044). The majority (92.1%) of patients with endometrial pathology had surgical management, and of these 85.7% were minimally invasive. Preoperative weight loss is a feasible option in gynaecologic oncology patients. Greater understanding of clinical significance, follow-up, and ideal target population for this intervention is needed.

What predicts the unsuccess of bariatric surgery? An observational retrospective study

PURPOSE

Bariatric surgery (BS) has been recognized as an effective treatment for most patients with morbid obesity, but a variable range of patients failed to achieve a successful weight-loss. Controversial data are available about predictors of unsuccess. We aimed to retrospectively assess whether clinical baseline characteristics of patients submitted to sleeve gastrectomy (SL) or gastric bypass (GBP) were associated with unsuccessful weight-loss after 12 and 24-month follow-up.

METHODS

Three hundred patients who underwent BS from the 1st January 2016, with at least 24-months follow-up, were enrolled. Patients were divided according to their percentage of excess weight-loss (%EWL) either < 50% or ≥ 50% after 12 and 24-month follow-up.

RESULTS

None of the patients was lost at follow-up; 56 (18.7%) patients showed a %EWL < 50% at 24 months. Age, neck circumference, obstructive sleep apnea (OSA) were significantly higher, while total cholesterol and %EWL 6-months lower in those with %EWL < 50% at 12-months. Age, neck circumference, male and OSA rates were increased, while %EWL at 6-months lower in patients with %EWL < 50% at 24-months. In a multiple regression model, age (OR = 1.076; 95% CI 1.029-1.125; p = 0.001; OR = 1.066; 1.027-1.107; p < 0.001) and %EWL at 6-months (OR = 0.876; 0.840-0.913; p < 0.001; OR = 0.950; 0.928-0.972; p < 0.001) were associated with %EWL < 50% both at 12- and 24-months, respectively, and neck circumference (OR = 1.142; 1.011-1.289; p = 0.032) with %EWL < 50% at 24-months.

CONCLUSION

Older age, larger neck circumference, and %EWL at 6-months were significantly associated with BS unsuccess, showing almost 90% of those patients an unsuccessful weight-loss early after surgery. Further larger studies with longer follow-up are needed to confirm these results.

Connectome-Based Prediction of Optimal Weight Loss Six Months After Bariatric Surgery

Despite bariatric surgery being the most effective treatment for obesity, a proportion of subjects have suboptimal weight loss post-surgery. Therefore, it is necessary to understand the mechanisms behind the variance in weight loss and identify specific baseline biomarkers to predict optimal weight loss. Here, we employed functional magnetic resonance imaging (fMRI) with baseline whole-brain resting-state functional connectivity (RSFC) and a multivariate prediction framework integrating feature selection, feature transformation, and classification to prospectively identify obese patients that exhibited optimal weight loss at 6 months post-surgery. Siamese network, which is a multivariate machine learning method suitable for small sample analysis, and K-nearest neighbor (KNN) were cascaded as the classifier (Siamese-KNN). In the leave-one-out cross-validation, the Siamese-KNN achieved an accuracy of 83.78%, which was substantially higher than results from traditional classifiers. RSFC patterns contributing to the prediction consisted of brain networks related to salience, reward, self-referential, and cognitive processing. Further RSFC feature analysis indicated that the connection strength between frontal and parietal cortices was stronger in the optimal versus the suboptimal weight loss group. These findings show that specific RSFC patterns could be used as neuroimaging biomarkers to predict individual weight loss post-surgery and assist in personalized diagnosis for treatment of obesity.

Pre-operative Predictors of Weight Loss and Weight Regain Following Roux-en-Y Gastric Bypass Surgery: a Prospective Human Study

BACKGROUND

There are currently few pre-operative predictors of initial and long-term weight loss following bariatric surgery.

OBJECTIVES

We evaluated the role of pre-operative patient characteristics and baseline gut and adipose-derived hormones in predicting maximal total body weight loss (WL_max) and risk of weight regain (WR) after Roux-en-Y gastric bypass (RYGB) surgery.

METHODS

One hundred five adult patients undergoing primary RYGB were prospectively recruited. Baseline demographics were recorded and fasting plasma glucose, glycosylated hemoglobin (A1C), insulin, glucagon, leptin, active ghrelin, glucagon-like peptide 1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP) levels were measured on day of surgery.

RESULTS

Our cohort had a mean age of 44.4 ± 13.0 years, and initial BMI (body mass index) of 45.1 ± 6.7 kg/m² with mean post-operative follow-up of 40 months. Eighty patients were female and 26 had type 2 diabetes mellitus (T2D). Average WL_max was 35.3 ± 7.4%. On univariate analysis, higher baseline fasting ghrelin, lower age, lower CRP (C-reactive protein), lower A1C, and negative T2D status were associated with greater WL_max (p < 0.05). Controlling for these variables using stepwise multivariate regression, only higher fasting ghrelin and younger age were associated significantly with greater WL_max (p < 0.05). In subgroup multivariate regression analysis of T2D patients, higher ghrelin and glucagon were significantly associated with greater WL_max. Following stepwise multivariate regression, lower initial BMI and lower glucagon were associated with greater WR (p < 0.05).

CONCLUSIONS

Incorporation of baseline biological and hormonal markers may help in developing more accurate predictive models for weight loss following bariatric surgery that help inform patient counseling and decision-making.

Short-Term Preoperative Weight Loss and Postoperative Outcomes in Bariatric Surgery

BACKGROUND

Preoperative weight loss is often encouraged before undergoing weight loss surgery. Controversy remains as to its effect on postoperative outcomes. The aim of this study was to determine what impact short-term preoperative excess weight loss (EWL) has on postoperative outcomes in patients undergoing primary vertical sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB).

STUDY DESIGN

All patients who underwent SG (n = 167) or RYGB (n = 188) between 2014 and 2016 and who completed our program-recommended low calorie diet (LCD) for 4 weeks immediately preceding surgery were included. These patients (N = 355) were then divided into 2 cohorts and analyzed according to those who achieved ≥8% EWL (n = 224) during the 4-week LCD period and those who did not (n = 131). Primary endpoints included percent excess weight loss (% EWL) at 1, 3, 6, and 12 months postoperatively.

RESULTS

Patients achieving ≥8% EWL preoperatively experienced a greater % EWL at postoperative month 3 (42.3 ± 13.2% vs 36.1 ± 10.9%, p < 0.001), month 6 (56.0 ± 18.1% vs 47.5 ± 14.1%, p < 0.001), and month 12 (65.1 ± 23.3% vs 55.7 ± 22.2%, p = 0.003). Median operative duration (117 minutes vs 125 minutes; p = 0.061) and mean hospital length of stay (1.8 days vs 2.1 days; p = 0.006) were also less in patients achieving ≥8% EWL. No significant differences in follow-up, readmission, or reoperation rates were seen. Linear regression analysis revealed that patients who achieved ≥8% EWL during the 4-week LCD lost 7.5% more excess weight at postoperative month 12.

CONCLUSIONS

Based on these data, preoperative weight loss of ≥8% excess weight, while following a 4-week LCD, is associated with a significantly greater rate of postoperative EWL over 1 year, as well as shorter operative duration and hospital length of stay.

Efficacy of a liquid low-energy formula diet in achieving preoperative target weight loss before bariatric surgery

A preoperative weight loss of 8 % is a prerequisite to undergo bariatric surgery (BS) in Denmark. The aim of the present study was to evaluate the efficacy of a 7- or an 11-week low-energy diet (LCD) for achieving preoperative target weight before BS. A total of thirty obese patients (BMI 46·0 (sd 4·4) kg/m(2)) followed an LCD (Cambridge Weight Plan(®), 4184 kJ/d (1000 kcal/d)) for 7 or 11 weeks as preparation for BS. Anthropometric measurements including body composition (dual-energy X-ray absorptiometry), blood parameters and blood pressure were assessed at weeks 0, 7 and 11. At week 7, the majority of patients (77 %) had reached their target weight, and this was achieved after 5·4 (sem 0·3) weeks. Mean weight loss was 9·3 (sem 0·5) % (P < 0·01) and consisted of 41·6 % fat-free mass (FFM) and 58·4 % fat mass. The weight loss was accompanied by a decrease in systolic and diastolic blood pressure (7·1 (sem 2·3) and 7·3 (sem 1·8) mmHg, respectively, all P < 0·01) as well as an improved metabolic profile (8·2 (sem 1·8) % decrease in fasting glucose (P < 0·01), 28·6 (sem 6·4) % decrease in fasting insulin (P < 0·01), 23·1 (sem 2·2) % decrease in LDL (P < 0·01), and 9·7 (sem 4·7) % decrease in TAG (P < 0·05)). Weight, FFM and fat mass continued to decrease from week 7 to 11 (all P < 0·01), whereas no additional improvements was observed in the metabolic parameters. Severely obese patients can safely achieve preoperative target weight on an LCD within 7 weeks as part of preparation for BS. However, the considerable reduction in FFM in severely obese subjects needs further investigation.

Bariatric surgery outcomes in ethnic minorities

BACKGROUND

The primary aim of this study was to examine percent excess weight loss (%EWL) across and between racial groups at 6, 12, 24, and 36 months follow-up in patients who received sleeve gastrectomy (SG) or a Roux-en-Y gastric bypass (RYGB) operation. We hypothesized that ethnic minorities (blacks and Hispanics) would have a lower %EWL than whites at 6, 12, 24, and 36 months for both SG and RYGB operations. The secondary aim was to examine %EWL within racial groups at 6, 12, 24, and 36 months as a function of the type of bariatric operation. We hypothesized that whites, blacks, and Hispanics would have a greater %EWL with RYGB than with SG.

METHODS

A total of 749 patients who underwent an SG or an RYGB operation from January 2008 to June 2014 were included. Data were collected from patients' electronic medical records. Self-reported data on race/ethnicity were also obtained from the electronic medical record and were classified into the following categories: white, Hispanic/Latino, African American or black, or other.

RESULTS

Results revealed overall differences in %EWL between blacks and whites (P < .05) and no overall differences in %EWL between Hispanics and whites (P = .697). Follow-up analyses revealed that Hispanics differed from blacks in %EWL at 6, 12, 24, and 36 months (all P < .01) and that whites differed from blacks at 6 months (P < .05). There were no significant differences between whites and Hispanics during any follow-up period. Overall, the %EWL differed by operation type (P < .01), with RYGB associated with greater %EWL than SG. When stratified by race, the only difference was found in blacks, who had a greater %EWL after RYGB compared with SG (P < .01).

CONCLUSION

Our primary hypothesis was partially supported, as blacks but not Hispanics had a lower %EWL compared to whites at 6 months. An interesting finding is that blacks had a lower %EWL than Hispanics at every time point. Moreover, our secondary hypothesis was partially supported. Results revealed that overall RYGB was related to greater %EWL compared with SG, and within racial groups, among blacks only, RYGB was associated with a greater %EWL compared with SG.

Efficacy of a Required Preoperative Weight Loss Program for Patients Undergoing Bariatric Surgery

The efficacy of mandatory medically supervised preoperative weight loss (MPWL) prior to bariatric surgery continues to be a controversial topic. The purpose of this observational study was to assess the efficacy of a MPWL program in a single institution, which mandated at least 10% excess body weight loss before surgery, by comparing outcomes of patients undergoing primary bariatric surgery with and without a compulsory preoperative weight loss regimen. We analyzed our database of 757 patients who underwent primary bariatric surgery between March 2008 and January 2015. Patients were placed into two cohorts based on their participation in a MPWL program requiring at least 10% excess weight loss (EWL) prior to surgery. Patients were evaluated at 3, 6, 12, and 24 months after surgery for weight loss, comorbidity resolution, and the occurrences of hospital readmissions. A total of 717 patients met the inclusion criteria of whom 465 underwent surgery without a preoperative weight loss requirement and 252 participated in the MPWL program. One year after surgery, 67.1% of non-participants and 62.5% of MPWL participants showed a resolution of at least one of five associated comorbidities (p = 0.45). Non-participants showed an average of 58.6% EWL, while MPWL participants showed 59.1% EWL at 1 year postoperatively (p = 0.84). Readmission rates, excluding those which were ulcer-related, at 30 days (3.4 vs. 6.40%, p = 0.11) and 90 days (9.9 vs. 7.5%, p = 0.29) postoperatively were not significantly different between the non-participants and MPWL patients, respectively. A mandatory preoperative weight loss program prior to bariatric surgery did not result in significantly greater %EWL or comorbidity resolution 1 year after surgery compared to patients not required to lose weight preoperatively. Additionally, the program did not result in significantly lower 30- or 90-day readmission rates for these patients. The value of a MPWL program must be weighed against the potential loss of bariatric surgery candidates. Patients who fail to lose 10% excess weight preoperatively are thus ineligible for a procedure from which they would otherwise benefit. Our data suggest these patients will have similar positive outcomes.

Weight loss before gastric bypass and postoperative weight change: data from the Scandinavian Obesity Registry (SOReg)

BACKGROUND

Weight loss before bariatric surgery has been found to be associated with reduced rates of postoperative complications.

OBJECTIVE

To evaluate whether preoperative weight loss was also associated with improved postoperative weight loss over time and if this was dependent on preoperative body mass index (BMI).

SETTING

Data from the Swedish national registry for bariatric surgery.

METHODS

Out of 20,564 patients undergoing primary gastric bypass from January 1, 2008 to November 30, 2011, 9570 with complete data on preoperative weight loss and 2 years postoperative weight loss were analyzed.

RESULTS

Total preoperative weight loss in the 25th, 50th, and 75th percentiles was 0%, 4.5%, and 8.6%, respectively. When comparing patients in the 50th percentile for preoperative weight loss with those in the 25th percentile, total postoperative weight loss was 5.0% and 5.3% higher at 1 and 2 years, respectively (P<.001). Corresponding values for patients in the 75th percentile for preoperative weight loss were 11.8% and 10.1% (P< .001). For patients in the 75th percentile of preoperative BMI (>45.7 kg/m(2)) the effect was even more pronounced. Thus, in this group of patients and within the 75th percentile for preoperative weight loss, the total weight reduction after 1 and 2 years was 15.2% and 13.6% higher compared with patients in the 25th percentile for preoperative weight loss.

CONCLUSION

In this Swedish national bariatric registry data set, weight loss before gastric bypass was associated with sustained improved postoperative weight reduction. Moreover, there was a relationship between the degree of pre- and postoperative weight loss and the relationship was stronger in patients with high BMI.

Does Preoperative Weight Change Predict Postoperative Weight Loss After Laparoscopic Sleeve Gastrectomy?

Background: Some institutions and insurance companies mandate a preoperative weight loss regimen prior to bariatric surgery. Previous studies suggest little to no correlation between preoperative and postoperative weight loss for laparoscopic Roux-en-Y gastric bypass (RNYGB). This study examined the impact of preoperative weight change for patients undergoing laparoscopic sleeve gastrectomy (LSG). Materials and Methods: A retrospective analysis was performed on patients undergoing LSG at the authors' institution from 2010 to 2012. Patients were grouped based on preoperative weight gain or loss. The correlation between preoperative BMI change and postoperative BMI change was studied, as well as length of surgery. Results: Of 141 patients with 1-year follow-up, 72 lost, six maintained, and 64 gained weight preoperatively. Percentage of excess BMI loss at 1 year was not statistically different between those who lost weight and those who gained weight. Percent change in BMI from initial visit to surgery does not correlate with change in BMI at 1 year postoperatively or with length of surgery. Conclusions: Preoperative weight loss is not a reliable predictor of postoperative weight loss or shorter operative time after LSG. Potential patients who otherwise meet indications for LSG should not be denied based on inability to lose weight.

Predictors of weight loss 2 years after laparoscopic sleeve gastrectomy

INTRODUCTION

Despite the rapidly increasing popularity of laparoscopic sleeve gastrectomy (LSG), there is limited data examining weight loss more than 1 year after the procedure. There have also been few studies examining baseline predictors of weight loss after LSG. We aimed to examine the percentage of excess weight loss (%EWL) in patients 2 years after LSG and identify baseline predictors of %EWL.

METHODS

Electronic records from university hospitals were available for 292 patients who underwent LSG (205 women; mean age, 41.5 ± 11.1 years; mean weight, 126.5 ± 27.5 kg; mean BMI, 45.5 ± 7.5 kg/m(2) ). Variables assessed for predictive effect were baseline age, sex, BMI, presence of comorbidities (diabetes, hypertension, or obstructive sleep apnea), the amount of weight loss induced by a very low-calorie diet before surgery, and the number of clinic appointments attended over the 2 years. We performed linear regression and mixed model analyses between predictor variables and %EWL at 2 years.

RESULTS

Adjusted %EWL was 31% at 2 weeks, 49% at 3 months, 64% at 6 months, 70% at 9 months, 76% at 12 months, 79% at 18 months, and 79% at 2 years. Multivariate analysis showed that lower baseline BMI, absence of hypertension, and greater clinic attendance predicted better %EWL (r(2)  = 0.11).

CONCLUSION

Longer-term follow-up studies of weight loss post LSG are required to assist with patient care and management.

Effects of lifestyle interventions that include a physical activity component in class II and III obese individuals: a systematic review and meta-analysis

BACKGROUND

In class II and III obese individuals, lifestyle intervention is the first step to achieve weight loss and treat obesity-related comorbidities before considering bariatric surgery. A systematic review, meta-analysis, and meta-regression were performed to assess the impact of lifestyle interventions incorporating a physical activity (PA) component on health outcomes of class II and III obese individuals.

METHODS

An electronic search was conducted in 4 databases (Medline, Scopus, CINAHL and Sportdiscus). Two independent investigators selected original studies assessing the impact of lifestyle interventions with PA components on anthropometric parameters, cardiometabolic risk factors (fat mass, blood pressure, lipid and glucose metabolism), behaviour modification (PA and nutritional changes), and quality of life in adults with body mass index (BMI) ≥ 35 kg/m2. Estimates were pooled using a random-effect model (DerSimonian and Laird method). Heterogeneity between studies was assessed by the Cochran's chi-square test and quantified through an estimation of the I².

RESULTS

Of the 3,170 identified articles, 56 met our eligibility criteria, with a large majority of uncontrolled studies (80%). The meta-analysis based on uncontrolled studies showed significant heterogeneity among all included studies. The pooled mean difference in weight loss was 8.9 kg (95% CI, 10.2-7.7; p < 0.01) and 2.8 kg/m² in BMI loss (95% CI, 3.4-2.2; p < 0.01). Long-term interventions produced superior weight loss (11.3 kg) compared to short-term (7.2 kg) and intermediate-term (8.0 kg) interventions. A significant global effect of lifestyle intervention on fat mass, waist circumference, blood pressure, total cholesterol, LDL-C, triglycerides and fasting insulin was found (p<0.01), without significant effect on HDL-C and fasting blood glucose.

CONCLUSIONS

Lifestyle interventions incorporating a PA component can improve weight and various cardiometabolic risk factors in class II and III obese individuals. However, further high quality trials are needed to confirm this evidence, especially beyond weight loss.

Preoperative factors and 3-year weight change in the Longitudinal Assessment of Bariatric Surgery (LABS) consortium

BACKGROUND

Limited data guide the prediction of weight loss success or failure after bariatric surgery according to presurgery factors. There is significant variation in weight change after bariatric surgery and much interest in identifying preoperative factors that may contribute to these differences. This report evaluates the associations of a comprehensive set of baseline factors and 3-year weight change.

SETTING

Ten hospitals in 6 geographically diverse clinical centers in the United States.

METHODS

Adults undergoing a first bariatric surgical procedure as part of clinical care by participating surgeons were recruited between 2006 and 2009. Participants completed research assessments utilizing standardized and detailed data collection on over 100 preoperative and operative parameters for individuals undergoing Roux-en-Y gastric bypass (RYGB) and laparoscopic adjustable gastric banding (LAGB). Weight was measured 3 years after surgery. Percent weight change for RYGB or LAGB from baseline to 3 years was analyzed as both a continuous and dichotomous outcome with cut points at 25% for RYGB and 10% for LAGB. Multivariable linear and logistic regression models were used to identify independent baseline predictors of the continuous and categorical outcomes, respectively.

RESULTS

The median weight loss 3 years after surgery for RYGB (n = 1513) participants was 31.5% (IQR: 24.6%-38.4%; range, 59.2% loss to .9% gain) of baseline weight and 16.0% (IQR: 8.1%-23.1%; range, 56.1% loss to 12.5% gain) for LAGB (n = 509) participants. The median age was 46 years for RYGB and 48 years for LAGB; 80% of RYGB participants and 75% of LAGB participants were female; and the median baseline body mass index (BMI) was 46 kg/m(2) for RYGB and 44 kg/m(2) for LAGB. For RYGB, black participants lost 2.7% less weight compared with whites and participants with diabetes at baseline had 3.7% less weight loss at year 3 than those without diabetes at baseline. There were small but statistically significant differences in weight change for RYGB in those with abnormal kidney function and current or recent smoking. For LAGB participants, those with a large band circumference had 75% greater odds of experiencing less than 10% weight loss after adjusting for BMI and sex.

CONCLUSIONS

Few baseline variables were associated with 3-year weight change and the effects were small. These results indicate that baseline variables have limited predictive value for an individual's chance of a successful weight loss outcome after bariatric surgery.

TRIAL REGISTRATION

NCT00465829, ClinicalTrials.gov.

Weight loss prior to bariatric surgery: an updated review of the literature

BACKGROUND AND AIMS

Prior to bariatric surgery, a preoperative weight-reducing regimen is usually adhered to in most centers. The clinical effects of such a regimen are yet to be determined.

MATERIAL AND METHODS

We reviewed the current literature by searching in PubMed for publications reporting clinical effects resulting from a preoperative weight loss regimen prior to bariatric surgery published from January 1, 1995 to April 30, 2014.

RESULTS

In total, we identified 23 original publications and 2 review articles which met all inclusion criteria. These were included and fully analyzed with regard to effects of preoperative weight loss. In general, for parameters such as operating time and intraoperative complications including blood loss and recovery, inconsistent data were reported. Most studies included low number of patients and with heterogenic designs, and the results could not form the base for recommendations. However, for outcomes such as postoperative complications and weight development over time, data from large-scale studies and randomized controlled trials suggest beneficial effects following adherence to weight loss prior to bariatric surgery.

CONCLUSION

Although a large amount of data in the current literature on the effects of weight loss prior to bariatric surgery are inconsistent for many outcome parameters, recently published results regarding effects on postoperative complications and weight development over time strongly suggest that such a regimen should be recommended. Whether a certain degree of weight loss should be mandatory before being accepted for bariatric surgery is, however, still controversial.

Ethnicity influences weight loss 1 year after bariatric surgery: a study in Turkish, Moroccan, South Asian, African and ethnic Dutch patients

Several studies conducted in the USA have demonstrated that the effectiveness of bariatric surgery differs between patients from African and European origin. However, little is known on differences in outcomes after bariatric surgery between individuals from other ethnic backgrounds. In this retrospective study, we found that, in terms of weight loss, gastric bypass surgery is less effective in African, South Asian, Turkish and Moroccan patients than in their ethnic Dutch counterparts. Our results underscore that ethnic differences in the effectiveness of bariatric surgery are not limited to those between patients of African and European origin, but extend to other minority groups as well. Therefore, it is important that prospective studies both determine ethnic differences in weight loss-related improvement of co-morbidities and elucidate the exact reasons for these ethnic disparities.

Roux-en-Y gastric bypass patients hospitalized for substance use disorders achieve successful weight loss despite poor psychosocial outcomes

An emerging body of literature indicates that Roux-en-Y gastric bypass (RYGB) patients may be at a heightened risk for substance use disorders (SUDs) after surgery. Little is known about how weight loss and psychosocial outcomes of RYGB patients who develop SUD differ from those who do not. The present study compared weight loss and psychosocial outcomes of 26 post-RYGB patients in inpatient SUD treatment with those of 26 RYGB patients who did not evidence problematic substance use in the post-operative period. SUD and control cases were matched on age, sex and time lapse since surgery. No significant differences in % total weight loss or % excess weight loss (EWL) were found between groups. Those in SUD treatment were significantly less likely to meet the surgical failure criteria of <50% EWL but evidenced greater symptoms of depression, higher rates of probable major depressive disorder and poorer quality of life. Our findings indicate that RYGB patients hospitalized for SUDs achieve successful weight loss despite having poor psychosocial outcomes.

Roux-en-Y gastric bypass for morbid obesity: what are the preoperative predictors of weight loss?

Obesity has become an increasingly important health problem over the past 30 years. Presently around a quarter of the UK adult population are obese and this figure is set to increase further in the coming decades. The health consequences of obesity on multiple body systems have been well established as has the financial cost of the condition to both the individuals affected as well as to society as a whole. Bariatric surgery has been shown to be the only long term effective solution in terms of sustained weight loss and comorbidity resolution. The commonest bariatric procedure in the UK is the Roux-en-y gastric bypass which consistently results in the loss of 70%-80% of excess bodyweight. Results however are variable and in order to optimise resource allocation and avoid exposing patients unlikely to benefit from surgery to its inherent risks, much research has been done to try to identify those patients most likely to obtain a good result. The only factor which has been subjected to meta-analysis is that of preoperative weight loss which shows a positive association with postoperative weight loss following bypass surgery. Although the remaining data are not based on level 1 evidence those other preoperatively identifiable factors which are associated with an improved outcome include Caucasian or Hispanic ethnicity, higher educational status, non-shift-work working patterns, female gender and divorced or single marital status. Similarly increased levels of preoperative physical activity and an absence of binge eating behaviour are consistent with a favourable result whereas increased age, smoking and other socioeconomic factors have not been shown to have a significant impact. Conversely diabetes mellitus seems to have a slight negative correlation with postoperative weight loss; however, a history of sexual abuse or psychiatric illness has not been shown to have a lasting influence.

Ethnic differences in weight loss and diabetes remission after bariatric surgery: a meta-analysis

OBJECTIVE

It has been postulated that the effectiveness of bariatric surgery varies between ethnic groups. However, data regarding this topic are inconclusive, as most studies included few patients from minority groups. We conducted a meta-analysis to determine the difference in percentage of excess weight loss (%EWL) 1-2 years after bariatric surgery in people of African and Caucasian descent. We also studied differences in diabetes mellitus (DM) remission.

RESEARCH DESIGN AND METHODS

We performed a MEDLINE and EMBASE search for studies reporting %EWL and/or DM remission after bariatric surgery and including both African Americans and Caucasians. The 613 publications obtained were reviewed. We included 14 studies (1,087 African Americans and 2,714 Caucasians); all provided data on %EWL and 3 on DM remission. We extracted surgery type, %EWL, and DM remission 1-2 years after surgery. After analyzing %EWL for any surgery type, we performed subanalyses for malabsorptive and restrictive surgery.

RESULTS

The overall absolute mean %EWL difference between African Americans and Caucasians was -8.36% (95% CI -10.79 to -5.93) significantly in favor of Caucasians. Results were similar for malabsorptive (-8.39% [-11.38 to -5.40]) and restrictive (-8.46% [-12.95 to -3.97]) surgery. The remission of DM was somewhat more frequent in African American patients than in Caucasian patients (1.41 [0.56-3.52]). However, this was not statistically significant.

CONCLUSIONS

In %EWL terms, bariatric surgery is more effective in Caucasians than in African Americans, regardless of procedure type. Further studies are needed to investigate the exact mechanisms behind these disparities and to determine whether ethnic differences exist in the remission of comorbidities after bariatric surgery.

Preoperative predictors of weight loss following bariatric surgery: systematic review

BACKGROUND

Obesity affects 32% of adults in the USA. Surgery generates substantial weight loss, but 20-30% fails to achieve successful weight loss. Our objective was to identify preoperative psychosocial factors associated with weight loss following bariatric surgery.

METHODS

We performed a literature search of PubMed® and the Cochrane Database of Reviews of Effectiveness between 1988 and April 2010. Articles were screened for bariatric surgery and weight loss if they included a preoperative predictor of weight loss: body mass index (BMI), preoperative weight loss, eating disorders, or psychiatric disorder/substance abuse. One thousand seven titles were reviewed, 534 articles screened, and 115 included in the review.

RESULTS

Factors that may be positively associated with weight loss after surgery include mandatory preoperative weight loss (7 of 14 studies with positive association). Factors that may be negatively associated with weight loss include preoperative BMI (37 out of 62 studies with negative association), super-obesity (24 out of 33 studies), and personality disorders (7 out of 14 studies). Meta-analysis revealed a decrease of 10.1% excess weight loss (EWL) for super-obese patients (95% confidence interval (CI) [3.7-16.5%]), though there was significant heterogeneity in the meta-analysis, and an increase of 5.9% EWL for patients with binge eating at 12 months after surgery (95% CI [1.9-9.8%]).

CONCLUSIONS

Further studies are necessary to investigate whether preoperative factors can predict a clinically meaningful difference in weight loss after bariatric surgery. The identification of predictive factors may improve patient selection and help develop interventions targeting specific needs of patients.

Pre-bariatric surgery weight loss requirements and the effect of preoperative weight loss on postoperative outcome

Pre-bariatric surgery requirements vary between surgeons and surgical centers, with standards of practice not yet established. The goal of this systematic review was to summarize and evaluate the available literature on pre-bariatric surgery weight loss requirements and the relation between preoperative weight loss and postoperative outcome. Major databases, including Medline, PubMed and PsychINFO were searched for relevant articles. Case studies, studies>20 years old and studies that utilized self-reported body weight data were excluded. Data on the effect of the following was summarized: (1) preoperative requirements on preoperative weight loss; (2) insurance-mandated preoperative requirements; (3) the contingency of receipt of surgery; (4) preoperative weight loss on postoperative weight loss and (5) preoperative weight loss on perioperative and postoperative complication and comorbidity rates. The majority of studies suggest that: (1) current preoperative requirements held by the majority of third party payer organizations in the United States are ineffective in fostering preoperative weight loss; (2) making receipt of surgery contingent upon achieving preoperative weight loss, and meal-replacement diets, may be particularly effective in fostering preoperative weight loss and (3) preoperative weight loss may lead to improvements in at least some relevant postoperative outcomes. However, a preoperative weight loss mandate may lead to the denial of surgery and subsequent health benefits to individuals who are unable to achieve a prespecified amount of weight. Overall, the limited number and quality of prospective studies in this area prohibits the much-needed establishment of standards of practice for pre-bariatric requirements.

Current evidence for a role of GLP-1 in Roux-en-Y gastric bypass-induced remission of type 2 diabetes

Weight-reducing surgical procedures such as Roux-en-Y gastric bypass (RYGB) have proven efficient as means of decreasing excess body weight. Furthermore, some studies report that up to 80% of patients with type 2 diabetes mellitus (T2DM) undergoing RYGB experience complete remission of their T2DM. Interestingly, the majority of remissions occur almost immediately following the operation and long before significant weight loss has taken place. Following RYGB, dramatic increases in postprandial plasma concentrations of the incretin hormone glucagon-like peptide-1 (GLP-1) have been recorded, and the known antidiabetic effects of GLP-1 are thought to be key mediators in RYGB-induced remission of T2DM. However, the published studies on the impact of RYGB on GLP-1 secretion are few, small and often not controlled properly. Furthermore, mechanistic studies delineating the role of endogenous GLP-1 secretion in RYGB-induced remission of T2DM are lacking. This article critically evaluates the current evidence for a role of GLP-1 in RYGB-induced remission of T2DM.

[Preoperative weight loss in bariatric surgery candidate patients. evidence-based recommendations]

INTRODUCTION

Bariatric surgery is becoming increasingly more common in the treatment of morbid obesity in our hospitals. One of the measures being used to optimise the results of this surgery seems to be the standardising the preoperative weight loss. As there are no universal recommendations for carrying out this weight loss, a review of this topic is presented.

OBJECTIVES

To analyse whether sufficient scientific evidence exists to recommend preoperative weight loss in candidate patients for bariatric surgery. What would be the best options to carry out this weight loss is also analysed, as well as making some recommendations based on the scientific evidence.

RESULTS

There is great heterogeneity in the designs of the different studies, with different guidelines for weight loss and various surgical techniques. However, preoperative weight loss leads to a decrease in the size of the liver and intra-abdominal fat, which improves the surgical field and intra-operative view, which in turn helps during the surgical act, both in open as well as laparoscopic surgery. There is no consensus on the effect of preoperative weight loss has in predicting the medium or long term results after bariatric surgery.

CONCLUSION

The current scientific evidence makes preoperative weight loss recommendable in candidate patients for bariatric surgery. However, there is no consensus on what is the best procedure to achieve this preoperative weight loss.

The Effect of Preoperative Weight Loss before Gastric Bypass: A Systematic Review

Background. Many insurance companies require obese patients to lose weight prior to gastric bypass. From a previous study by the same authors, preoperative weight at surgery is strongly predictive of weight loss up to one year after surgery. This review aims to determine whether preoperative weight loss is also correlated with weight loss up to one year after surgery. Methods. Of the 186 results screened using PubMed, 12 studies were identified. A meta-analysis was performed to further classify studies (A class, B class, regression, and rejected). Results. Of all 12 studies, one met the criteria for A class, six were B class, four were regression, and one was rejected. Six studies supported our hypothesis, five were inconclusive, and no study refuted. Conclusions. Preoperative weight loss is additive to postsurgery weight loss as predicted from the weight at the time of surgery.

Effect of preoperative weight loss in bariatric surgical patients: a systematic review

BACKGROUND

The potential benefit of preoperative weight loss in patients undergoing bariatric surgery has led many bariatric surgeons to recommend an aggressive weight reduction regimen to their patients. Some surgeons might withhold bariatric procedures if a certain threshold of preoperative weight loss is not achieved. It is unclear whether this practice has any scientific evidence supporting it. Our study aimed to examine the current evidence surrounding this issue in a systematic review. The setting was a university hospital.

METHODS

A systematic search of multiple databases, including MEDLINE, Google Scholar, EMBASE, the Cochrane Library, and conference proceedings were reviewed, yielding a final total of 27 studies. Of the 27 studies, 7 were prospective studies (2 randomized controlled trials from the same patient population), 14 were retrospective studies (2 chart reviews from the same patient population), 1 was an editorial, and a number were conference presentations.

RESULTS

A total of 17 trials, including approximately 4611 patients, deemed preoperative weight loss beneficial, and 10 studies, including 2075 patients, deemed preoperative weight loss to be of no benefit. The operative time was 12.5 minutes shorter for the preoperative weight loss patients undergoing laparoscopic Roux-en-Y gastric bypass. With regard to the effects of preoperative weight loss on postoperative weight loss, 9 studies (39%) reported a positive correlation, and 15 (62.5%) reported no benefit. Nine studies reporting perioperative complications (852 patients) revealed no difference in the complication rates, and 2 studies (1234 patients) suggested a significant decrease was associated with preoperative weight loss.

CONCLUSION

This systematic review suggests little evidence is available to support or refute the routine use of preoperative weight reduction in bariatric surgery. Clearly, a large-scale, multicenter, randomized, controlled trial with sufficient power is necessary to clarify this significant aspect of preoperative care.

Preoperative 4-week low-calorie diet reduces liver volume and intrahepatic fat, and facilitates laparoscopic gastric bypass in morbidly obese

BACKGROUND

The aim of this study was to explore changes in liver volume and intrahepatic fat in morbidly obese patients during 4 weeks of low-calorie diet (LCD) before surgery and to investigate if these changes would facilitate the following laparoscopic gastric bypass.

METHODS

Fifteen female patients (121.3 kg, BMI 42.9) were treated preoperatively in an open study with LCD (800-1,100 kcal/day) during 4 weeks. Liver volume and fat content were assessed by magnetic resonance imaging and spectroscopy before and after the LCD treatment.

RESULTS

Liver appearance and the complexity of the surgery were scored at the operation. Eighteen control patients (114.4 kg, BMI 40.8), without LCD were scored similarly. Average weight loss in the LCD group was 7.5 kg, giving a mean weight of 113.9 kg at surgery. Liver volume decreased by 12% (p < 0.001) and intrahepatic fat by 40% (p < 0.001). According to the preoperative scoring, the size of the left liver lobe, sharpness of the liver edge, and exposure of the hiatal region were improved in the LCD group compared to the controls (all p < 0.05).

CONCLUSIONS

The overall complexity of the surgery was perceived lower in the LCD group (p < 0.05), due to improved exposure and reduced psychological stress (both p < 0.05). Four weeks of preoperative LCD resulted in a significant decrease in liver volume and intrahepatic fat content, and facilitated the subsequent laparoscopic gastric bypass as scored by the surgeon.

Weight loss prior to bariatric surgery is not a pre-requisite of excess weight loss outcomes in obese patients

BACKGROUND

Although weight loss before bariatric surgery may carry advantages during the surgical procedure (decreased liver volume, operation duration, and blood loss), it is still debated whether it induces a greater long-term weight loss.

METHODS

We conducted a retrospective analysis over 539 patients operated by the same surgeon until September 2008. Five hundred seven primary bariatric surgical procedures were performed: gastric bypass in 381, gastric banding in 97, and sleeve gastrectomy in 29. Preoperative multidisciplinary care was similar for all the patients over a period of 12 months. Relationship between weight changes during this period and the percentage of excess weight loss (%EWL) over the 48 month after surgery was analyzed by logistic regression.

RESULTS

No relationship could be evidenced between pre- and postoperative weight loss, regardless of the surgical technique performed. Whether patients were male or female, and whether they had an initial BMI greater or lower than 50 kg/m(2), did not make a difference in the relationship between EWL at any point and weight loss prior to surgery. Despite a large range of weight changes before surgery, there was no trend for a relationship.

CONCLUSIONS

This study suggests that weight loss before surgery should not be considered a pre-requisite. Although it can reduce the difficulties of the surgical procedure, advantages for long-term weight loss are not validated.

Effectiveness of a prebariatric surgery insurance-required weight loss regimen and relation to postsurgical weight loss

Most US insurance companies require patients to participate in a medically supervised weight loss regimen prior to bariatric surgery. However, the utility of this requirement has not been documented. Data was collected from 94 bariatric surgery patients who were required, and 59 patients who were not required, by their insurance company to participate in a presurgical weight loss regimen. Weight change in the required group, as well as group differences in weight change, was examined from 3 and 6 months presurgery to 1 week presurgery, and from 1 week presurgery to 3 months postsurgery. Weight change presurgery was then used to predict weight loss postsurgery. In the 6 months prior to surgery, required patients gained 3.7 kg +/- 5.9 (s.d.) (P < 0.0005), which did not differ from nonrequired patients. From surgery to 3 months postsurgery, required patients lost 23.6 +/- 8 kg (P < 0.0005), also without differing from nonrequired patients. Patients who gained more weight prior to surgery, lost more weight postsurgery (P = 0.001), while controlling for initial weight. Findings suggest that the common weight loss regimen requirements of US insurance carriers were ineffective in producing presurgical weight loss in this sample. Most patients (>70%) in this sample gained weight prior to surgery, potentially taking advantage of final opportunities to overindulge in preferred foods. Required patients fared no better in terms of weight change postsurgically and, surprisingly, presurgical weight gain predicted better postsurgical weight loss outcome. Several potential explanations for this finding are offered.

Does weight loss immediately before bariatric surgery improve outcomes: a systematic review

BACKGROUND

Preoperative weight loss before bariatric surgery has been proposed as a predictive factor for improved patient compliance and the degree of excess weight loss achieved after surgery. In the present study, we sought to determine the effect of preoperative weight loss on postoperative outcomes.

METHODS

A search of MEDLINE was completed to identify the patient factors associated with weight loss after bariatric surgery. Of the 909 screened reports, 15 had reported on preoperative weight loss and the degree of postoperative weight loss achieved. A meta-analysis was performed that compared the postoperative weight loss and perioperative outcomes in patients who had lost weight preoperatively compared to those who had not.

RESULTS

Of the 15 articles (n = 3404 patients) identified, 5 found a positive effect of preoperative weight loss on postoperative weight loss, 2 found a positive short-term effect that was not sustained long term, 5 did not find an effect difference, and 1 found a negative effect. A meta-analysis revealed a significant increase in the 1-year postoperative weight loss (mean difference of 5% EWL, 95% confidence interval 2.68-7.32) for patients who had lost weight preoperatively. A meta-analysis of other outcomes revealed a decreased operative time for patients who had lost weight preoperatively (mean difference 23.3 minutes, 95% confidence interval 13.8-32.8).

CONCLUSION

Preoperative weight loss before bariatric surgery appears to be associated with greater weight loss postoperatively and might help to identify patients who would have better compliance after surgery.