Preoperative Weight Gain Is Not Related to Lower Postoperative Weight Loss, But to Lower Total Weight Loss up to 3 Years After Bariatric-Metabolic Surgery

INTRODUCTION

Weight loss prior to bariatric-metabolic surgery (BMS) is recommended in most bariatric centers. However, there is limited high-quality evidence to support mandatory preoperative weight loss. In this study, we will evaluate whether weight gain prior to primary BMS is related to lower postoperative weight loss.

METHODS

A retrospective analysis of prospectively collected data was performed. Preoperative weight loss (weight loss from start of program to day of surgery), postoperative weight loss (weight loss from day of surgery to follow-up), and total weight loss (weight loss from start of program to follow-up) were calculated. Five groups were defined based on patients' preoperative weight change: preoperative weight loss of >5 kg (group I), 3-5 kg (group II), 1-3 kg (group III), preoperative stable weight (group IV), and preoperative weight gain >1 kg (group V). Linear mixed models were used to compare the postoperative weight loss between group V and the other four groups (I-IV).

RESULTS

A total of 1928 patients were included. Mean age was 44 years, 78.6% were female, and preoperative BMI was 43.7 kg/m2. Analysis showed significantly higher postoperative weight loss in group V, compared to all other groups at 12, 24, and 36 months follow-up. Up to three years follow-up, highest total weight loss was observed in group I.

CONCLUSION

Weight gain before surgery should not be a reason to withhold a bariatric-metabolic operation. However, patients with higher preoperative weight loss have higher total weight loss. Therefore, preoperative weight loss should be encouraged prior to bariatric surgery.

Influence of preoperative weight loss on gastric wall thickness-analysis of laparoscopic sleeve gastrectomy histological material

PURPOSE

The variables possibly enabling the prediction of gastric wall thickness during laparoscopic sleeve gastrectomy remain undetermined. The aim of the study was to identify preoperative factors affecting gastric wall thickness in patients undergoing laparoscopic sleeve gastrectomy.

METHODS

The measurements of the double-wall thickness of gastric specimen excised during sleeve gastrectomy were taken at three locations after 15 s of compression with an applied pressure of 8 g/mm². Statistical calculations were used to determine the influence of preoperative weight loss and other perioperative parameters on gastric wall thickness.

RESULTS

The study involved one hundred patients (78 female; 22 male). The thickest tissue was observed at the antrum with the mean value 2.55 mm (range 1.77-4.0 mm), followed by the midbody, mean 2.13 mm (range 1.34-3.20 mm), and the fundus, mean 1.69 mm (range 0.99-2.69 mm). Positive relationships were found between gastric wall thickness and both preoperative weight loss and age in all three measured locations; p < 0.05. In a linear regression model, age and preoperative weight loss were found to be statistically significant and positive predictors of higher gastric wall thickness only at the antrum. Male patients were observed to have thicker gastric wall at all three locations as compared to female patients.

CONCLUSION

Preoperative weight loss should be considered an important factor influencing gastric wall thickness. Age and gender can also be helpful in predicting the varying tissue thickness. Anatomical region is a key factor determining thickness of the stomach walls.

Impact of preoperative body mass index and weight loss on morbidity and mortality following colorectal cancer-a retrospective cohort study

PURPOSE

Body weight and preoperative weight loss (WL) are controversially discussed as risk factors for postoperative morbidity and mortality in colorectal cancer surgery. The objective of this study is to determine whether body mass index (BMI) or WL is associated with a higher postoperative complication rate.

METHODS

In this retrospective cohort study, data analysis of 1241 consecutive patients undergoing colorectal cancer surgery in an 11-year period was performed. The main outcome measures were wound infections (WI), anastomotic leakages (AL), and in-house mortality.

RESULTS

A total of 697 (56%) patients with colon and 544 (44%) with rectum carcinoma underwent surgery. The rate of WI for each location increased with rising BMI. The threshold value was 28.8 kg/m2. Obese patients developed significantly more WI than normal-weight patients did following rectal resection (18.0% vs. 8.2%, p = 0.018). Patients with preoperative WL developed significantly more AL following colon resections than did patients without preoperative WL (6.2% vs. 2.5%, p = 0.046). In-house mortality was significantly higher in obese patients following colon resections than in overweight patients (4.3% vs. 0.4%, p = 0.012). Regression analysis with reference to postoperative in-house mortality revealed neither increased BMI nor WL as an independent risk factor.

CONCLUSIONS

Increased preoperative BMI is associated with a higher WI rate. AL rate after colon resection was significantly higher in patients showing preoperative WL. Preoperative BMI and WL are therefore risk factors for postoperative morbidity in this study. Nevertheless, this has to be further clarified by means of prospective studies. Trial registration DRKS00025359, 21.05.2021, retrospectively registered.

Higher Preoperative Weight loss Is Associated with Greater Weight Loss up to 12 Months After Bariatric Surgery

BACKGROUND

Prior research suggested presurgical weight loss is associated with greater total weight loss, resulting in a more effective bariatric intervention. We aimed to assess whether preoperative weight loss is a predictor for total weight loss, and which patient factors are associated with successful weight loss.

METHODS

All patients (N = 773) that underwent primary bariatric surgery between June 2017 and August 2019 were included in this single-center retrospective study. Outcome measures were preoperative weight loss (%preopWL) and total weight loss (%TWL) up to 1 year postoperatively. Patients were divided into 4 groups based on quartiles of %preopWL.

RESULTS

Total weight loss after 1, 6, and 12 months for the upper quartile was 16.9%, 33.4%, and 37.8%, and for the lower quartile 11.8%, 28.9%, and 35.2%, respectively (p < 0.001). Seven hundred fourteen patients (92.4%) were available for the 1-year follow-up. Preoperative weight loss was not associated with the incidence of complications. Independent factors predicting increased %preopWL were mandated preoperative weight loss program (MWP) (p < 0.001), older age (p = 0.005), weight measurement in the week before surgery (p = 0.031), and non-diabetic status (p = 0.010). Predictors for superior %TWL were MWP (p = 0.014), younger age (p = 0.001), non-diabetic status (p = 0.005), female gender (p = 0.001), higher Body Mass Index (p = 0.006), and banded gastric bypass (p = 0.001).

CONCLUSION

Higher preoperative weight loss is associated with persisting greater weight loss up to at least 12 months post-surgery. In order to optimize preoperative weight loss, we recommend extra preoperative support to younger and diabetic patients. We advise nutritional counseling and additional weight measurement in the week before surgery.

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.

Impact of Preoperative Weight Loss on Postoperative Weight Loss Revealed from a Large Nationwide Quality Registry

PURPOSE

Weight loss before bariatric surgery is not mandatory, but questions remain as to whether preoperative weight loss has an impact on weight loss after surgery. Most studies have small sample sizes. The objective was to evaluate the relationship between preoperative and successful postoperative weight loss defined as ≥25% total weight loss (TWL) at 1 and 2 years after primary bariatric surgery with regard to the obesity-related comorbidities.

MATERIALS AND METHODS

Data were extracted from a large nationwide quality registry of patients who underwent a sleeve gastrectomy (SG) or gastric bypass (GBP) between January 2015 and January 2018. Patients with completed screening and preoperative and postoperative data were included. A multivariate logistic regression analysis was performed for each technique and follow-up years separately.

RESULTS

In total, 8751 were included in the analysis. Patients with preoperative weight loss were more likely to achieve ≥25% postoperative TWL in both procedures. Patients with higher preoperative weight loss of 5-10% had an increased likelihood for achieving 25% TWL compared to 0-5%, OR 1.79 (CI (1.42-2.25), p < 0.001) vs 1.25 (CI (1.08-1.46), p < 0.004) for the GBP group for year 2 postoperative. This was the same for the SG group at year 2, OR 1.30 (CI (1.03-1.64), p < 0.029) vs 1.14 (CI (0.94-1.38), p < 0.198).

CONCLUSION

Patients with preoperative weight loss were more likely to achieve ≥25% postoperative TWL at 1 and 2 years after surgery in both procedures; moreover, the extent of preoperative weight loss contributes to the significance and odds of this success.

Preoperative weight loss is linked to improved mortality and leaks following elective bariatric surgery: an analysis of 548,597 patients from 2015-2018

BACKGROUND

The effects of preoperative weight loss on bariatric surgery outcomes are still unclear, despite the practice being adopted by bariatric centers worldwide. Ongoing studies are needed for routine adoption of this practice given the multiple issues patients face with following difficult preoperative weight loss protocols.

OBJECTIVES

The aim of this study was to characterize the prevalence of preoperative weight loss and evaluate its impact on outcomes following elective bariatric surgery.

SETTING

This retrospective study was conducted using the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) data registry from 2015-2018.

METHODS

All primary Roux-en-Y (RYGB) and sleeve gastrectomy (SG) procedures were included, whereas prior revisional surgeries and emergency surgeries were excluded. Cases were then divided into preoperative weight loss (PWL) and control cohorts. PWL was defined categorically if the highest 30-day preoperative weight was greater than the closest recorded weight before surgery. Primary outcomes included identifying the impact of PWL on postoperative complications. Multivariable logistic regression modelling was used to examine the influence of PWL on serious complications and mortality after adjusting for patient co-morbidities and procedure type.

RESULTS

A total of 548,597 patients were identified with the majority experiencing preoperative weight loss (n= 459,500; 83.8%). The PWL cohort was older (44.8 ± 12.0 versus 43.2 ± 11.9 yr), had a reduced body mass index (BMI) (45.0 ± 7.4 versus 46.1 ± 7.6 kg/m²), and was more likely to be male (20.3% versus 18.7%). Patients with preoperative weight loss also were more likely to have metabolic co-morbidities including medication and insulin-dependent diabetes (27.0% versus 23.2%), hypertension (HTN) (48.9% versus 44.7%), dyslipidemia (DLP ) (24.6% versus 21.0%), and sleep apnea (39.6% versus 32.3%). No clinically significant differences were observed for operative length between cohorts (85.3 ± 46.9 min PWL versus 83.9 ± 46.2 min control). The protective benefit was found to be most significant for patients experiencing greatest weight loss with those experiencing a >10% PWL showing 30% decreased odds of leak (OR .68%; 95% CI [confidence interval] .56-.84; P < .0001) and a 40% decrease in odds of mortality versus those with no PWL (OR .60; 95% CI .39-.92; P = .02).

CONCLUSION

Preoperative weight loss before bariatric surgery is common, occurring in >80% of elective cases. Our findings suggest that preoperative weight loss is associated with improved odds of 30-day mortality and leaks but no differences in bleeds or overall serious complications. Additional prospective trials are needed to further evaluate the role of routine PWL in addition to ongoing development of tolerable preoperative weight-loss protocols.

Ventral Hernia Management in Obese Patients

Ventral and incisional hernias in obese patients are particularly challenging. Suboptimal outcomes are reported for elective repair in this population. Preoperative weight loss is ideal but is not achievable in all patients for a variety of reasons, including access to bariatric surgery, poor quality of life, and risk of incarceration. Surgeons must carefully weigh the risk of complications from ventral hernia repair with patient symptoms, the ability to achieve adequate weight loss, and the risks of emergency hernia repair in obese patients.

Do Mandated Weight Loss Goals Prior to Bariatric Surgery Improve Postoperative Outcomes?

BACKGROUND

Most patients pursuing bariatric surgery undergo mandated preoperative weight management programs. The purpose of this study was to assess whether preoperative mandated weight loss goals lead to improved perioperative morbidity, postoperative weight loss, and resolution of comorbidities.

METHODS

Data from patients who underwent primary laparoscopic Roux-en-Y gastric bypass (LRYGB), and laparoscopic sleeve gastrectomy (LSG) between October 2012 and October of 2015 was reviewed. Patients were divided in two groups: those with BMI of 35-45 were not required to achieve a weight loss goal prior to surgery (no-WLG group) while those with BMI > 45 were given a weight loss goal proportionate to their weight (WLG group). Body mass index (BMI), history of diabetes mellitus type-II (DM-II), hypertension (HTN), hyperlipidemia (HLD), and obstructive sleep apnea (OSA) were recorded at baseline and 4 years postoperatively. Length of hospital stay (LOS) and reinterventions were considered proxies for postoperative morbidity.

RESULTS

A total of 776 patients, 81.4% LRYGB, were included in the study (age 45.1 ± 11.9). There was no difference in %ΔBMI, DM-II, HDL, HTN, LOS, or reinterventions among the two groups at 4 years postoperatively in both LRNY and LSG patients. This lack of difference persisted even when patients with similar BMI (43-45 vs 45.01-47) were compared.

CONCLUSION

WLG group did not have decreased perioperative morbidity, nor improved weight loss and comorbidity resolution 4 years after surgery. While these findings should also be confirmed by multicenter trials, they question the value of mandated WLG prior to bariatric surgery as they seem ineffective and may limit patient access to surgery.

Weight loss after bariatric surgery: a comparison between delayed and immediate qualification according to the last resort criterion

BACKGROUND

In the Netherlands, patients only qualify for bariatric surgery when they have followed a 6-month mandatory weight loss program (MWP), also called the "last resort" criterion. One of the rationales for this is that MWPs result in greater weight loss.

OBJECTIVES

To determine weight loss during MWPs and the effect of delayed versus immediate qualification on weight loss 3 years after bariatric surgery.

SETTING

Outpatient clinic.

METHODS

This is a nationwide, retrospective study with prospectively collected data. All patients who underwent a primary bariatric procedure in 2016 were included. We compared weight loss between patients who did not qualify according to the last resort criterion at screening (delayed group) with patients that qualified (immediate group).

RESULTS

In total 2628 patients were included. Mean age was 44.4 years, 81.3% were female, and baseline BMI was 42.3 kg/m². Roux-en-Y gastric bypass (RYGB) was the most frequently performed surgery (77.0%), followed by sleeve gastrectomy (15.8%) and banded RYGB (7.3%). The delayed group (n = 831; 32%) compared with immediate group (n = 1797; 68%), showed less percentage of total weight loss (%TWL) during the MWP (1.7% versus 3.9%, P < .001) and time between screening and surgery was longer (42.3 versus 17.5 wk, P < .001). Linear mixed model analysis showed no significant difference in %TWL at 18- (P = .291, n = 2077), 24- (P = .580, n = 1993) and 36-month (P = .325, n = 1743) follow-up.

CONCLUSION

This study shows that delayed qualification for bariatric surgery compared with immediate qualification does not have a clinically relevant impact on postoperative weight loss 3 years after bariatric surgery.

Total weight loss after laparoscopic Roux-en-Y gastric bypass is influenced by preoperative weight loss: can we predict the outcome?

BACKGROUND

Preoperative weight loss (WL) is associated with higher postoperative WL at 1- to 2-year follow-up in patients who undergo laparoscopic Roux-en-Y gastric bypass (LRYGB).

OBJECTIVE

To evaluate the possible association between preoperative and postoperative WL at 3-year follow-up and identify risk factors for insufficient WL.

SETTING

A single-center prospective cohort study in the Netherlands.

METHODS

Patients undergoing primary LRYGB and laparoscopic conversion from band to bypass (redo LRYGB) were instructed to lose weight preoperatively. Follow-up data were collected 1, 2, and 3 years postoperatively. WL was described as percentage total weight loss (%TWL) and percentage excess body mass index (BMI) loss. Patients were divided into 2 groups: group A lost any amount of weight; group B did not lose any weight or gained weight preoperatively.

RESULTS

Group A consisted of 230 patients (median preoperative %TWL, 4.8%), and group B consisted of 46 patients (median preoperative %TWL, -1.3%). Median BMI at intake was 44.1 kg/m². Baseline characteristics were similar. The %TWL and BMI for group A and B in the patients who underwent primary LRYGB at 1, 2, and 3 years was 32.2% (BMI, 28.6 kg/m²) versus 23.9% (BMI, 32.2 kg/m²), 31.8% (BMI, 28.9 kg/m²) versus 25.2% (BMI, 31.9 kg/m²), and 33.3% (BMI, 29.7 kg/m²) versus 21.9% (BMI, 34 kg/m²), respectively, all P < .05. In patients who underwent redo LRYGB no clinically significant differences in postoperative BMI were found.

CONCLUSIONS

Preoperative WL in primary patients who undergo LRYGB can be useful to identify those at risk of inadequate postoperative WL. In patients who undergo redo LRYGB different risk factors should be considered for prediction of inadequate postoperative WL.

Weight loss during medical weight management does not predict weight loss after bariatric surgery: a retrospective cohort study

BACKGROUND

Many bariatric surgical centers mandate achieving weight loss targets through medical weight management (MWM) programs before offering bariatric surgery, but the evidence for this is unclear.

OBJECTIVES

To examine the relationship between weight changes during (1) MWM, and (2) preoperative low-energy-diet (LED), and weight changes at 12 and 24 months after surgery.

SETTING

Multicenter community- and acute-based MWM services referring to one regional bariatric center, United Kingdom.

METHODS

A retrospective cohort study of patients who attended MWM and then underwent a primary laparoscopic bariatric procedure (adjustable gastric banding [LAGB], or Roux-en-Y gastric bypass [RYGB]) in a single bariatric center in the United Kingdom between 2013 and 2015. Data were collected from patient electronic records.

RESULTS

Two hundred eight patients were included (LAGB n = 128, RYGB n = 80). Anthropometric data were available for 94.7% and 88.0% of participants at 12 and 24 months, respectively. There was no relationship between weight loss during MWM and after surgery at either 12 or 24 months. Weight loss during the preoperative LED predicted greater weight loss after LAGB (β = .251, P = .006) and less weight loss after RYGB (β = -.390, P = .003) at 24 months, after adjusting for age, sex, ethnicity, baseline weight, and LED duration.

CONCLUSIONS

Weight loss in MWM does not predict greater weight loss outcomes up to 24 months after LAGB or RYGB. Greater weight loss during the preoperative LED predicted greater weight loss after LAGB and less weight loss after RYGB. Our results suggest that patients should not be denied bariatric surgery because of not achieving weight loss in MWM. Weight loss responses to preoperative LEDs as a predictor of postsurgical weight loss requires further investigation.

Weight Loss Prior to Bariatric Surgery and 30-Day Mortality, Readmission, Reoperation, and Intervention: an MBSAQIP Analysis of 349,016 Cases

INTRODUCTION

Despite preoperative weight loss being a common prerequisite to metabolic and bariatric surgery, its relationship to 30-day postoperative outcomes is unclear. The aim of this study was to assess whether preoperative weight loss is associated with 30-day postoperative quality outcomes in adults undergoing metabolic and bariatric surgery.

METHODS

Retrospective cohort study assessing adults who underwent Roux-en-Y gastric bypass or sleeve gastrectomy in the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program Participant Use File, years 2015-2017. The relationship between preoperative weight loss and 30-day readmission, reoperation, mortality, intervention, and morbidity was assessed using multivariable logistic regression.

RESULTS

Preoperative weight loss, body mass index loss, and percent weight loss were not associated with 30-day postoperative overall readmission, reoperation, mortality, or intervention (p > 0.01). Preoperative percent weight loss was associated with increased incidence of superficial surgical site infections (OR = 1.023, 95% CI 1.009-1.036; p = 0.001) and urinary tract infections (OR = 1.044, 95% CI 1.030-1.059; p < 0.001).

CONCLUSION

Weight loss prior to metabolic and bariatric surgery may not be necessary or safe for all patients. Unsafe weight loss prior to surgery may compromise nutrition status and lead to increased infection rates.

Influence of Preoperative Weight Loss on Outcomes of Bariatric Surgery for Patients Under the Enhanced Recovery After Surgery Protocol

INTRODUCTION

The enhanced recovery after surgery (ERAS) protocol, which emphasizes preoperative interventions, is safely implemented in patients undergoing bariatric surgery. Patients are additionally encouraged to achieve weight loss preoperatively. We aimed to identify factors contributing to preoperative weight loss and assess their influence on outcomes of bariatric surgery among patients under the ERAS protocol.

MATERIALS AND METHODS

We reviewed a prospectively created database in two bariatric centers with 909 bariatric patients treated in accordance with ERAS principles. The database included demographic characteristics, factors related to the surgery or perioperative period, and short-term outcomes. Our endpoints included analyses of (1) factors potentially contributing to preoperative weight loss and (2) the influence of preoperative weight loss on short-term outcomes of bariatric treatment.

RESULTS

Diabetes mellitus (p = 0.007), obstructive sleep apnea (p < 0.001), and previous surgery (p = 0.012) were identified as predictors of preoperative weight loss. Steatohepatitis (p < 0.001) and respiratory disorder (p = 0.004) decreased the chance of achieving satisfactory preoperative body mass reduction. Except for operative time, early outcomes of bariatric surgery were not influenced by preoperative weight loss. Patients who achieved preoperative weight loss were less likely to be lost to follow-up (p = 0.023). Postoperative weight loss was better in patients who could lose ≥ 5% total weight preoperatively (p = 0.009).

CONCLUSION

Unsatisfactory preoperative weight loss among patients treated under ERAS principles is not associated with increased risk of complications. Satisfactory preoperative weight loss predicts superior postoperative weight loss and follow-up participation.

Perioperative and Postoperative Effects of Preoperative Low-Calorie Restrictive Diets on Patients Undergoing Laparoscopic Sleeve Gastrectomy

OBJECTIVE

A restrictive diet applied before bariatric surgery can be required to reduce the liver volume or as a necessity imposed by insurance companies. However, the benefits of preoperative weight loss remain controversial. The present study aimed to investigate the perioperative and postoperative outcomes of a restrictive diet applied before laparoscopic sleeve gastrectomy.

MATERIALS AND METHODS

The data of 128 patients who received surgery in 2015 and 2016 were retrospectively analyzed. All patients were advised to follow a 4-week low-calorie (1000 cal) restrictive diet. Nevertheless, approximately 50% of patients did not accept the diet plan. We divided the patients into two groups as dieters (group 1) and non-dieters (group 2).

RESULTS

In group 1, changes in after-diet BMI and liver size were statistically significant (p < 0.001). In group 2, mean operation duration, mean hospitalization duration values, mean BMI values, and mean body weight at postoperative 1, 3, 6, and 12 months were statistically significantly higher than in group 1. No statistically significant difference was found between early complication rates of the groups (p = 0.844).

CONCLUSION

Low-calorie restrictive diet applied before laparoscopic sleeve gastrectomy has reduced liver volume and shortens surgery and hospitalization time but does not have any significance concerning early complications and weight loss after operation in 1 year. Also, non-adherence of the bariatric surgery candidate patients to the diet seems to be a challenge.

Impact of a preoperative low-calorie diet on liver histology in patients with fatty liver disease undergoing bariatric surgery

BACKGROUND

A low-calorie diet (LCD) before bariatric surgery has been shown to reduce liver volume and facilitate ease of operation. It is estimated that 75%-100% of individuals undergoing bariatric surgery have nonalcoholic fatty liver disease (NAFLD).

OBJECTIVES

We aimed to investigate how an LCD affects liver histology in the setting of NAFLD.

SETTING

University Hospital, United States.

METHODS

Forty intraoperative liver specimens were analyzed histologically as follows: 20 with and 20 without a preoperative 2-week, 1200 kcal/d LCD. Weight was measured prediet, at surgery, and 6 months after surgery. NAFLD activity score was used to grade liver histology at surgery. The NAFLD activity score scores steatosis, lobular inflammation, hepatocellular ballooning, and fibrosis.

RESULTS

The non-LCD group (n = 20) had mean weight at surgery of 136.1 ± 24.1 kg. The LCD group (n = 20) had initial mean weight of 128.6 ± 25.4 kg, with presurgical weight loss of 3.43 kg (range, 0-9.3 kg), mean change in body mass index 1.24 kg/m² (2.66% total weight loss) on an LCD. The LCD group had significantly less steatosis (P = .02), fewer foci of lobular inflammation (P = .01), and less hepatocellular ballooning (P = .04) compared with the non-LCD group; with no difference in degree of fibrosis. Fewer patients in the LCD group had nonalcoholic steatohepatitis with ballooning (P = .04). Weight loss on an LCD before bariatric surgery was predictive of weight loss 6 months after surgery (P = .026).

CONCLUSIONS

A 2-week LCD before bariatric surgery is associated with significant improvement in steatosis, inflammation, and hepatocellular ballooning in NAFLD. Among LCD patients, preoperative weight loss was associated with improved 6-month weight loss and liver function.

Bridging interventions before bariatric surgery in patients with BMI ≥ 50 kg/m2: a systematic review and meta-analysis

BACKGROUND

Bariatric surgery on patients with body mass index (BMI) ≥ 50 kg/m², historically known as superobesity, is technically challenging and carries a higher risk of complications. Bridging interventions have been introduced for weight loss before bariatric surgery in this population. This systematic review and meta-analysis aims to assess the efficacy and safety of bridging interventions before bariatric surgery in patients with BMI ≥ 50 kg/m².

METHODS

MEDLINE, EMBASE, Web of Science, and Scopus were searched from database inception to September 2018. Studies were eligible for inclusion if they conducted any bridging intervention for weight loss in patients with BMI greater than 50 kg/m² prior to bariatric surgery. Primary outcome was the change in BMI before and after bridging intervention. Secondary outcomes included comorbidity status after bridging interventions and resulting complications. Pooled mean differences (MD) were calculated using random effects meta-analysis.

RESULTS

13 studies including 550 patients met inclusion criteria (mean baseline BMI of 61.26 kg/m²). Bridging interventions included first-step laparoscopic sleeve gastrectomy (LSG), intragastric balloon (IGB), and liquid low-calorie diet program (LLCD). There was a reduction of BMI by 12.8 kg/m² after a bridging intervention (MD 12.8, 95% CI 9.49-16.1, P < 0.0001). Specifically, LSG demonstrated a BMI reduction of 15.2 kg/m² (95% CI 12.9-17.5, P < 0.0001) and preoperative LLCD by 9.8 kg/m² (95% CI 9.82-15.4, P = 0.0006). IGB did not demonstrate significant weight loss prior to bariatric surgery. There was remission or improvement of type 2 diabetes, hypertension, and sleep apnea in 62.8%, 74.6%, and 74.6% of patients, respectively.

CONCLUSIONS

First-step LSG and LLCD are both safe and appropriate bridging interventions which can allow for effective weight loss prior to bariatric surgery in patients with BMI greater than 50 kg/m².

Executive Function, Eating Behavior, and Preoperative Weight Loss in Bariatric Surgery Candidates: An Observational Study

BACKGROUND

Individual differences in executive function may influence eating behavior, weight loss (WL), and WL maintenance in obesity treatment. Executive function, which designates top-down cognitive control processes, has been related to eating behaviors which may impact weight, and has been found to be predictive of WL in both behavioral WL programs and after bariatric surgery. Currently, we lack knowledge on the role of executive function in the period before bariatric surgery. If executive function impacts eating behavior and WL in the preoperative period, it may be a target for clinical attention in this stage.

OBJECTIVES

We aimed to examine the relationship between objective performance-based measures of executive function, eating patterns, and WL in the preoperative period.

METHOD

Baseline data in an ongoing observational longitudinal study of bariatric surgery patients were used. Eighty patients completed neuropsychological testing and self-report questionnaires 4 weeks prior to surgery.

RESULTS

We found that working memory predicted WL before surgery and inhibitory control predicted adherence to dietary recommendations.

CONCLUSION

Our study indicates that executive function may play a role in short-term WL and dietary adherence prior to surgery, suggesting that executive function in the preoperative period deserves an extended research focus.

Commercial Very Low Energy Meal Replacements for Preoperative Weight Loss in Obese Patients: a Systematic Review

BACKGROUND

This systematic review assessed feasibility and effectiveness of preoperative meal replacements to improve surgical outcomes for obese patients.

METHODS

PRISMA guidelines were followed and electronic databases searched for articles between January 1990 and March 2015.

RESULTS

Fifteen studies (942 participants including 351 controls) were included, 13 studies (n = 750) in bariatric patients. Adverse effects and dropout rates were minimal. Ten out of 14 studies achieved 5-10 % total weight loss. Six of six studies reporting liver volume achieved 10 % reduction. Endpoints for perioperative risks and outcomes were too varied to support definitive risk benefit.

CONCLUSIONS

Commercial meal replacements are feasible, have minimal side effects and facilitate weight loss and liver shrinkage in free-living obese patients awaiting elective surgery. A reduction in surgical risk is unclear.

Preoperative Medical Weight Management in Bariatric Surgery: a Review and Reconsideration

Bariatric surgery is the most robust treatment for extreme obesity. The impact of preoperative medical weight management sessions designed, in theory, with the primary goal of promoting preoperative weight loss, is unclear. This paper reviews studies that have investigated the relationship between preoperative weight loss and bariatric surgical outcomes, both with respect to postoperative weight loss and complications. We conclude that the most robust of preoperative interventions has not been implemented or evaluated in a manner which would conclusively assess the value of this element of care. We offer a reconsideration of the role of preoperative medical weight management and provide recommendations for future research in this area.

Effects of very low calorie diets on liver size and weight loss in the preoperative period of bariatric surgery: a systematic review

Restrictive diet implementation in bariatric surgery (BS) preoperative period is common, although its benefits are not well established. This study aimed to assess the effects of very low calorie diets (VLCD) on liver size and weight loss during BS preoperative period. Surgery-related complications were also assessed. A systematic review of the literature was performed. Terms such as "bariatric surgery" and "very low energy diet" were included in the search strategy. Inclusion criteria were adult patients (aged>18 yr); VLCD treatment in BS preoperative period (10 d to 12 wk); and assessment of 1 the following outcomes: weight loss, liver volume reduction, and surgical complications. There were 9 studies included (849 patients including 250 controls, 196 controls without VLCD). Of the studies, 3 were randomized clinical trials and 6 were observational studies. VLCD treatment led to weight loss (-2.8 to -14.8 kg) and to liver size reduction by 5% to 20% of the initial volume. VLCD treatment did not significantly reduce perioperative complications. However, 1 study (n = 273) reported a protective effect 30 days after surgery. This systematic review found VLCD treatment led to significant weight loss and liver volume reduction when applied to patients with obesity in BS preoperative period. The effect of VLCD on surgical risks is not clear. Standardization of dietary characteristics is needed, because weight loss and decrease in liver size were not connected to higher caloric restriction. This is an important matter in clinical practice as to avoid unnecessary prolonged and/or excessive dietary restriction.

Evidence Base for Optimal Preoperative Preparation for Bariatric Surgery: Does Mandatory Weight Loss Make a Difference?

PURPOSE OF REVIEW

Preoperative weight loss regimens prior to bariatric surgery have been a routine and common practice for many centers, in the US and around the world. The mandated participation in such programs has largely been influenced by loco-regional payer requirements. The relationship between adherence to a mandatory weight loss regimen and achieved preoperative weight loss as well as the clinical impact of preoperative weight loss on bariatric outcomes remains uncertain.

RECENT FINDINGS

This review examines the available current literature, in the context of previous findings, regarding the impact of mandated preoperative weight loss regimens and mandatory weight loss on bariatric outcomes. The reviewed studies do not provide sufficient evidence that mandatory participation in a preoperative weight loss regimen prior to bariatric surgery is associated with achieved weight loss or durable bariatric outcome benefit. Preoperative weight loss, when achieved, may confer a positive benefit on postoperative complications; however, this is not a consistent finding in the literature and requires further validation. The practice of mandating participation in a preoperative weight loss regimen or requiring mandatory weight loss prior to bariatric surgery is not supported by current literature and may serve as an obstacle to medically necessary and potentially life-saving treatment.

Qualifying for bariatric surgery: is preoperative weight loss a reliable predictor of postoperative weight loss?

BACKGROUND

Over the last 20 years, bariatric surgery has emerged as a highly effective weight loss intervention that can also improve co-morbid medical conditions. However, some payors have required preoperative supervised diets and weight loss.

OBJECTIVE

To determine if preoperative weight loss is the best predictor of postoperative weight loss.

SETTING

Academic county hospital, United States.

METHODS

A retrospective chart review of 218 patients. Patients who received psychological evaluation and bariatric surgery were followed up at 1 year. All preoperative patients were encouraged to lose weight; however, no specified amount of weight loss was required. Preoperative weight loss and postoperative weight loss in body mass index (BMI), percent excess weight loss, and percent total weight loss were measured. Bariatric outcome predictor variables evaluated included age, race, and sex; BMI change; measures of depression and anxiety; number of unhealthy eating types; and co-morbid medical conditions. A linear regression model and stepwise regression analyses were used to estimate contributions of independent variables to the 1-year weight loss.

RESULTS

All patients had a mean 28% reduction in BMI (63.3% excess weight loss and 29.1% total weight loss) at 1 year postoperatively. As a single independent variable, preoperative weight loss was a significant predictor of 1-year change in postoperative BMI (P = .006). However, when age, race, and sex were added to the regression equation, the predictive value of preoperative weight loss became nonsignificant (P = .543).

CONCLUSION

The present findings indicate that preoperative weight loss should not be considered in isolation when clearance for bariatric surgery is being evaluated.

Predictors of preoperative weight loss achievement in adult bariatric surgery candidates while following a low-calorie diet for 4 weeks

BACKGROUND

Achieving program-mandated preoperative weight loss poses a challenge for many bariatric surgery candidates. No systematic method exists to identify at-risk patients early in preoperative care.

OBJECTIVES

This study sought to explore predictors of preoperative weight loss achievement and to develop a treatment algorithm for guiding clinical decision-making.

SETTING

Greenville Health System, South Carolina.

METHODS

A retrospective chart review was conducted for 378 patients who followed a program-mandated low-calorie diet (LCD) for 4 weeks to achieve≥8% excess weight loss (EWL). Associations between weight loss achievement and patient demographic, nutrition, psychological, clinical, anthropometric, and treatment characteristics documented at 5 preoperative evaluation events were analyzed using logistic regression.

RESULTS

During the LCD, 62.7% of patients achieved≥8% EWL. Independent predictors of achievement (all P<.05) were male sex (OR 2.31, 95% CI 1.21-4.42), Caucasian race (OR 2.45, 95% CI 1.38-4.34), body mass index (BMI) at surgeon evaluation (50.0-59.9 kg/m²: OR .44, 95% CI .20-.97;≥60 kg/m²: OR .15, 95% CI .05-.42), number of co-morbidities (OR .83, 95% CI .74-.93), hypertension diagnosis (OR 2.42, 95% CI 1.42-4.13), prediet weight change (OR 1.08, 95% CI 1.01-1.16), and time between surgeon evaluation and preoperative LCD initiation (61-90 d: OR .46, 95% CI .23-.93).

CONCLUSION

Patients of female sex or non-Caucasian race; with a BMI≥50 kg/m², many co-morbidities, or no hypertension diagnosis at surgeon evaluation; who demonstrate prediet weight loss or extended wait time between surgeon evaluation and preoperative LCD initiation may be at risk for preoperative weight loss failure and may require preemptive diet modification to improve outcomes.

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.

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.

Outcomes associated with preoperative weight loss after laparoscopic Roux-en-Y gastric bypass

BACKGROUND

Laparoscopic Roux-en-Y gastric bypass (LRYGB) is an effective treatment for achieving and maintaining weight loss and for improving obesity-related comorbidities. As part of the approval process for bariatric surgery, many insurance companies require patients to have documented recent participation in a supervised weight loss program. The goal of this study was to evaluate the relationship of preoperative weight changes with outcomes following LRYGB.

METHODS

A retrospective review was conducted of adult patients undergoing LRYGB between 2008 and 2012 at a single institution. Patients were stratified into quartiles based on % excess weight gain (0-4.99 % and ≥5 % EWG) and % excess weight loss (0-4.99 % and ≥5 % EWL). Generalized linear models were used to examine differences in postoperative weight outcomes at 6, 12, and 24 months. Covariates included in the final adjusted models were determined using backwards stepwise selection.

RESULTS

Of the 300 patients included in the study, there were no significant demographic differences among the quartiles. However, there was an increased time to operation for patients who gained or lost ≥5 % excess body weight (p < 0.001). Although there was no statistical significance in postoperative complications, there was a higher rate of complications in patients with ≥5 % EWG compared to those with ≥5 % EWL (12.5 vs. 4.8 %, respectively; p = 0.29). Unadjusted and adjusted generalized linear models showed no statistically significant association between preoperative % excess weight change and weight loss outcomes at 24 months.

CONCLUSION

Patients with the greatest % preoperative excess weight change had the longest intervals from initial visit to operation. No significant differences were seen in perioperative and postoperative outcomes. This study suggests preoperative weight loss requirements may delay the time to operation without improving postoperative outcomes or weight loss.