Clinical factors associated with weight loss outcomes after Roux-en-Y gastric bypass surgery

Postoperative continuation of antidepressant therapy is associated with reduced short-term weight loss following Roux-en-Y gastric bypass surgery

PURPOSE

Bariatric surgery candidates are frequently treated with antidepressants. Several of these drugs have been associated with weight gain and could potentially interfere with weight loss after bariatric surgery. This cohort study aimed to investigate the short-term effects of antidepressants on weight loss during the first 24 months after a Roux-en-Y gastric bypass.

METHODS

Patients with a fully documented antidepressant treatment status for at least 12 months were retrospectively included. Weight loss was expressed as the percentage excess BMI loss (%EBMIL) or percentage total weight loss (%TWL). A mixed linear effects model was used to determine the impact of continued and discontinued treatment with antidepressants on weight loss.

RESULTS

A total of 751 patients were included in this study. At 24 months, patients had lost 77.38 ± 30.10 %EBMIL (30.63 ± 13.12 %TWL). In patients treated with antidepressants (n = 125), the %EBMIL and %TWL was reduced with - 2.81% (p = 0.025) and - 1.36% (p = 0.002) respectively, and with - 5.52 %EBMIL (p < 0.001; - 1.05 %TWL, p = 0.012) after multivariate adjustment. Serotonin-norepinephrine reuptake inhibitors (- 12.47 %EBMIL, p < 0.001) and tricyclic antidepressants (- 11.01 %EBMIL, p = 0.042) were predominantly responsible for worse outcomes. Beyond 24 months, at 36 months (- 4.83%, p < 0.001) and 48 months (- 3.54%, p = 0.006), the %EBMIL was still reduced. No significant effects of antidepressants on metabolic outcomes after surgery were observed.

CONCLUSIONS

Treatment with antidepressants was associated with reduced weight loss after gastric bypass surgery, but only if treatment was continued for at least 1 year postoperatively. Mainly tricyclic antidepressants and serotonin-norepinephrine reuptake inhibitors were responsible for this reduction in weight loss.

Prospective assessment of fibrinolysis in morbid obesity: tissue plasminogen activator resistance improves after bariatric surgery

BACKGROUND

Morbid obesity is associated with an increased risk of thrombotic events, which has been attributed to increased thrombotic activity. Multiple mechanisms have been proposed to explain this increased risk, including an inflammatory state with upregulation of procoagulant and antifibrinolytic proteins. We therefore hypothesize that patients with morbid obesity are hypercoagulable and will revert to normal after bariatric surgery.

OBJECTIVES

To evaluate changes in the hypercoagulable state after bariatric surgery.

SETTING

University Hospital, Bariatric Center of Excellence, United States.

METHODS

Thromboelastography (TEG) data were collected on 72 subjects with morbid obesity, with 36 who had 6 months of follow-up after bariatric surgery. TEG data of 75 healthy subjects (HS) without obesity, recent trauma or surgery, acute infection, or chronic conditions (e.g., liver, cardiovascular, or kidney disease; cancer; diabetes; autoimmune or inflammatory disorders; and disorders of coagulation) were used for comparison. TEG was performed alone and with the addition of 75 and 150 ng/mL tissue plasminogen activator (tPA) to quantify fibrinolysis resistance (tPA-challenged TEG).

RESULTS

The bariatric surgery cohort had a median age of 40.5 years, a median body mass index of 44.6 kg/m², and 90% female patients. Median body mass index reduced significantly 6 months post surgery but remained elevated compared with the HS group (31.4 versus 25.4 kg/m², P < .0001). At 6 months post surgery, subjects had longer reaction time (mean difference, 1.3; P = .02), lower maximum amplitude (-2.4, P = .01), and increased fibrinolysis with low-dose (3.1, P < .0001) and high-dose tPA-challenged TEG (9, P < .0001). Compared with HS, the postsurgery TEG values were still more likely to be abnormal (all P < .05).

CONCLUSIONS

Patients with morbid obesity form stronger clots more rapidly and are more resistant to fibrinolysis than subjects without obesity. Bariatric surgery significantly improved the hypercoagulable profile and fibrinolysis resistance of morbid obesity.

Laparoscopic Gastroileal Bypass with Single Anastomosis: Analysis of the First 1512 Patients

BACKGROUND

Biliopancreatic diversion is perceived as the most effective operation for long-term treatment of massive obesity. The purpose of this study is to demonstrate that gastroileal bypass with single anastomosis is a safe and feasible procedure with similar results to the classic derivation, but reducing surgical time without decreasing the efficacy.

METHODS

Descriptive, observational, prospective study of patients undergoing gastroileal bypass with single anastomosis between April 2010 and December 2015. The postoperative follow-up was 24 months.

RESULTS

One thousand five hundred twelve patients underwent gastroileal bypass. The mean time of the procedure was 32 min; the average stay was 2.2 days. 30.1% of patients lost more than 100% of their excess weight, and 72.35% of patients lost more than 75% of their excess weight. 95.17% of patients dropped to a BMI < 35; 75.99% to a BMI < 30 and 30.15% to a BMI < 25.

CONCLUSIONS

Gastroileal bypass with single anastomosis is a safe and fast procedure providing similar results to biliopancreatic diversion with respect to weight loss.

A Nationwide Safety Analysis of Discharge on the First Postoperative Day After Bariatric Surgery in Selected Patients

BACKGROUND

Enhanced recovery after surgery has led to early recovery and shorter hospital stay after laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG). This study aims to assess feasibility and outcomes of postoperative day (POD) 1 discharge after LRYGB and LSG from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) 2015 dataset.

METHODS

Patients who underwent elective LRYGB and LSG and were discharged on POD 1 and 2 were extracted from the MBSAQIP dataset. A 1:1 propensity score matching was performed between cases with POD 1 vs POD 2 discharge, and the 30-day outcomes of the cohorts were compared.

RESULTS

A total of 80,464 patients met the study criteria: 8862 LRYGB and 31,370 LSG cases, which were discharged on POD 1, and matched 1:1 with those discharged on POD 2. Within the LRYGB cohort, patients discharged on POD 2 had higher all-cause morbidity (7.5% vs 6.1%; p < 0.001) and 30-day re-intervention (2.0% vs 1.5%; p = 0.004) in comparison with patients discharged on POD 1. There were no statistical differences with respect to serious morbidity (0.5% vs 0.4%; p = 0.15), 30-day readmission (4.9% vs 4.5%; p = 0.2), and 30-day reoperation (1.3% vs 1.2%; p = 0.7). Within the LSG cohort, patients discharged on POD 2 had higher all-cause morbidity (4.2% vs 3.4%; p < 0.001), serious morbidity (0.4% vs 0.3%; p < 0.001), 30-day re-intervention (1.0% vs 0.6%; p < 0.001), and 30-day readmission (2.9% vs 2.5%; p = 0.002) in comparison with patients discharged on POD 1.

CONCLUSIONS

Early discharge on POD 1 may be safe in a selective group of bariatric patients without significant comorbidities.

Failed Sleeve Gastrectomy: Single Anastomosis Duodenoileal Bypass or Roux-en-Y Gastric Bypass? A Multicenter Cohort Study

BACKGROUND

Sleeve gastrectomy (SG) has become the most performed bariatric procedure to induce weight loss worldwide. Unfortunately, a significant portion of patients show insufficient weight loss or weight regain after a few years.

OBJECTIVE

To investigate the effectiveness of the single anastomosis duodenoileal (SADI) bypass versus the Roux-en-Y gastric bypass (RYGB) on health outcomes in morbid obese patients who had undergone SG previously, with up to 2 years of follow-up.

METHODS

From 2007 to 2017, 140 patients received revisional laparoscopic surgery after SG in four specialized Dutch bariatric hospitals. Data was analyzed retrospectively and included comparisons for indication of surgery, vitamin/mineral deficiencies, and complications; divided into short-, medium-term. To compare weight loss, linear regression and linear mixed models were used.

RESULTS

Conversion of a SG to SADI was performed in 66 patients and to RYGB in 74 patients. For patients in which additional weight loss was the main indication for surgery, SADI achieved 8.7%, 12.4%, and 19.4% more total body weight loss at 6, 12, and 24 months compared to RYGB (all p < .001). When a RYGB was indicated in case of gastroesophageal reflux or dysphagia, it greatly reduced complaints almost directly after surgery. Furthermore, a similar amount of complications and nutritional deficiencies was observed for both groups. There was no intra- or post-operative mortality.

CONCLUSION

Conversion into a SADI resulted in significantly more weight loss while complications rates and nutritional deficiencies were similar and may therefore be considered the recommended operation for patients in which only additional weight loss is required.

Eating Behaviour Predicts Weight Loss Six Months after Bariatric Surgery: A Longitudinal Study

Bariatric surgery is currently the most durable weight loss solution for patients with morbid obesity. The extent of weight loss achieved, however, is subject to variation due to various factors, including patients' behaviour. In this study, we aimed to identify pre- and post-surgical predictors of weight loss following bariatric surgery. This prospective study included 57 participants who went through bariatric surgery (laparoscopic Roux-en-Y gastric bypass: n = 30; laparoscopic sleeve gastrectomy: n = 23; one anastomosis gastric bypass-mini gastric bypass: n = 4) in two tertiary referral hospitals. Consenting participants were assessed prior to surgery (T₀), and three months (T₁) and six months (T₂) after surgery. The assessment included interview and anthropometric measurements. The interview was done with the aid of instruments, including the Hospital Anxiety and Depression Scale (HADS) for anxiety and depression screening and the Dutch Eating Behaviour Questionnaire (DEBQ) for eating behaviour assessment. Baseline comorbidity status was obtained from medical records. A Generalised Estimating Equation (GEE) was developed to determine predictors of weight loss. Participants in the study were mostly women (n = 37, 65%) with a mean age of 39.4 (SD = 10.01) years. The mean excess BMI loss (EBMIL) and total weight loss (TWL) at the sixth month was 63.31% and 23.83%, respectively. Anxiety, depression, and external eating scores reduced over time. Advancing age, high BMI, and higher scores for emotional and external eating emerged as significant negative predictors for TWL%. It can be concluded that the patients experienced substantial weight loss after surgery. Continuous monitoring of psychological well-being and eating behaviour are essential for optimal weight loss.

Polygenic risk score for predicting weight loss after bariatric surgery

BACKGROUND

The extent of weight loss among patients undergoing bariatric surgery is highly variable. Herein, we tested the contribution of genetic background to such interindividual variability after biliopancreatic diversion with duodenal switch.

METHODS

Percentage of excess body weight loss (%EBWL) was monitored in 865 patients over a period of 48 months after bariatric surgery, and two polygenic risk scores were constructed with 186 and 11 (PRS186 and PRS11) single nucleotide polymorphisms previously associated with body mass index (BMI).

RESULTS

The accuracy of the %EBWL logistic prediction model - including initial BMI, age, sex, and surgery modality, and assessed as the area under the receiver operating characteristics (ROC) curve adjusted for optimism (AUCadj = 0.867) - significantly increased after the inclusion of PRS186 (ΔAUCadj = 0.021; 95% CI of the difference [95% CIdiff] = 0.005-0.038) but not PRS11 (ΔAUCadj= 0.008; 95% CIdiff= -0.003-0.019). The overall fit of the longitudinal linear mixed model for %EBWL showed a significant increase after addition of PRS186 (-2 log-likelihood = 12.3; P = 0.002) and PRS11 (-2 log-likelihood = 9.9; P = 0.007). A significant interaction with postsurgery time was found for PRS186 (β = -0.003; P = 0.008) and PRS11 (β = -0.008; P = 0.03). The inclusion of PRS186 and PRS11 in the model improved the cost-effectiveness of bariatric surgery by reducing the percentage of false negatives from 20.4% to 10.9% and 10.2%, respectively.

CONCLUSION

These results revealed that genetic background has a significant impact on weight loss after biliopancreatic diversion with duodenal switch. Likewise, the improvement in weight loss prediction after addition of polygenic risk scores is cost-effective, suggesting that genetic testing could potentially be used in the presurgical assessment of patients with severe obesity.

FUNDING

Heart and Stroke Foundation of Canada (G-17-0016627) and Canada Research Chair in Genomics Applied to Nutrition and Metabolic Health (no. 950-231-580).

The long-term effect of pregnancy on weight loss after sleeve gastrectomy

BACKGROUND

Pregnancy outcomes after bariatric surgery have been addressed extensively; however, the impact of pregnancy on long-term outcomes after bariatric surgery has only been sparsely studied.

OBJECTIVES

We explored the effects of pregnancy on weight loss outcomes after laparoscopic sleeve gastrectomy (LSG).

SETTING

University hospital.

METHODS

A cross-sectional case-control study. Eighty women who became pregnant after LSG were matched by preoperative body mass index, age, and follow-up duration to 80 post-LSG patients who did not conceive after surgery (control group).

RESULTS

The median follow-up duration was 5.2 years for the study group and 5.3 years for the control group (P = .73). For the study group, the median time from surgery to conception was 508 (interquartile range 372-954) days and the median gestational weight gain was 9 (6-12) kg. Comparing the study with the control group, median percentage total weight loss was similar, 31% versus 30% (P = .77); as was percentage excess weight loss (EWL%) 72% versus 71% (P = .77). For the study group, a multivariable analysis showed EWL% at the end of follow-up to be directly correlated with the lowest EWL% achieved before pregnancy (β = .78, P < .0001), and inversely correlated with time lapsed from surgery (β = -.26, P < .0001); yet EWL% was not found to be associated with surgery-to-conception time interval, gestational weight gain, breastfeeding, co-morbidities, smoking, occupational status, physical activity, and dietary habits.

CONCLUSIONS

Pregnancy after LSG does not affect long-term weight results. Coupled with the positive reports of improved pregnancy outcomes after bariatric surgery, these data should reassure women who wish to conceive after surgery.

Baseline Anthropometric and Metabolic Parameters Correlate with Weight Loss in Women 1-Year After Laparoscopic Roux-En-Y Gastric Bypass

BACKGROUND

In this study, we explored in a prospective cohort of morbidly obese women undergoing laparoscopic Roux-en-Y gastric bypass (LRYGP) correlations between baseline anthropometrics, metabolic parameters, resting energy expenditure (REE), body composition, and 1-year % excess body mass index loss (%EBMIL). We also investigated risk factors for insufficient %EBMIL.

METHODS

One hundred three consecutive women were prospectively evaluated at baseline (age 40.6 ± 11.2, weight 113.9 kg ± 15.3, BMI 43.3 ± 4.9 kg/m²) and 1 year after LRYGP. Weight, excess weight, brachial circumference, waist circumference, fat mass (FM) and fat-free mass (FFM) (measured with bioelectrical impedance analysis), REE, inflammation, insulin resistance, and lipid disturbances were determined before and 1 year after LRYGP.

RESULTS

At 1 year, mean weight loss was 39.8 kg ± 11.7 and mean EBMIL was 15.2 kg/m² ± 4.2. Mean %EBMIL was 86% ± 21% (range 30-146%). Baseline brachial circumference, waist circumference and triceps skinfold thickness decreased significantly at 1 year (P < 0.001). Blood glucose and insulin levels, HDL cholesterol, LDL cholesterol, triglycerides, and CRP also decreased significantly (P < 0.001). The mean loss of initial FFM and FM was 9.1 kg ± 8.2 (15%) and 30.7 kg ± 11.8 (53%), respectively. REE on body weight ratio (REE/BW) increased from 15.3 kcal/kg ± 2.8 to 18.4 kcal/kg ± 2.5 (p < 0.0001) and REE on FFM ratio decreased from 31.2 to 28.7 kcal/day/kg (p < 0.001). Preoperative waist circumference (r = -0.3; P < 0.001), blood glucose level (r = -0.37; P < 0.001), and CRP (r = -0.28; P = 0.004) were negatively correlated with EBMIL% 1 year after surgery. Among baseline body composition parameters, only preoperative FM was negatively correlated with %EBMIL (r = -0.23; p = 0.02). One year after surgery FM change was negatively correlated with EBMIL% (r = -0.49; P < 0.001) while FFM/BW ratio was positively correlated with %EBMIL (r = 0.71; P < 0.001). Increase in REE/BW at 1 year was positively correlated with %EBMIL (r = 0.47; p < 0.001). On multivariate analysis, baseline blood glucose level (OR = 1.77; CI 95%: [1.3-2.4]) was the only predictive factor of EBMIL <60% at 1 year.

CONCLUSION

LRYGB has beneficial effects on clinical, biological parameters, and body composition. Increasing the proportion of FFM on total BW and REE/BW is associated with better results in terms of weight loss. Baseline glucose level may be helpful in identifying poor responders to LRYGBP.

TRIAL REGISTRATION

NCT02820285y ( https://clinicaltrials.gov/ct2/show/NCT02820285?term=Characterization+of+Immune+Semaphorin+in+Non-Alcoholic+Fatty+Liver+Disease+and+NASH&rank=1 ).

Comparative Outcomes of Bariatric Surgery in Patients with Impaired Mobility and Ambulatory Population

PURPOSE

This study aims to characterize complications, metabolic improvement, and change in ambulation status for patients with impaired mobility undergoing bariatric surgery.

MATERIAL AND METHODS

Individuals undergoing primary sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) from February 2008 to December 2015 were included. Impaired mobility (WC) was defined as using a wheelchair or motorized scooter for at least part of a typical day. The WC group was propensity score matched to ambulatory patients (1:5 ratio). Comparisons were made for 30-day morbidity and mortality and 1-year improvement in weight-related comorbidities.

RESULTS

There were 93 patients in the WC group matched to 465 ambulatory controls. The median operative time (180 vs 159 min, p = 0.003) and postoperative length of stay (4 vs 3 days, p ≤ 0.001) was higher in the WC group. There were no differences in readmission or all-cause morbidity within 30 days. The median percent excess weight loss (%EWL) at 1 year was similar (WC group, 65% available, 53% EWL vs AMB group, 73% available, 54% EWL); however, patients with impaired mobility were less likely to experience improvement in diabetes (76 vs 90%, p = 0.046), hypertension (63 vs 82%, p < 0.005), and obstructive sleep apnea (53 vs 71%, p < 0.001). Within the WC group, 62% had improvement in their mobility status, eliminating dependence on wheelchair or scooter assistance.

CONCLUSION

Patients with both obesity and impaired mobility experience similar rates of perioperative morbidity and weight loss at 1 year compared to ambulatory controls. However, improvement in weight-related comorbidities may be less likely with impaired mobility.

Taste and Olfactory Changes Following Laparoscopic Gastric Bypass and Sleeve Gastrectomy

BACKGROUND

Alterations in taste/smell after bariatric surgery have been observed, but few data is available. Some authors documented these changes and their role on weight loss but there is no evidence after laparoscopic sleeve gastrectomy (LSG).

METHODS

Cohort study with patients submitted to laparoscopic gastric bypass (LGBP) and LSG that were asked to participate in a validated survey. The primary objective was to determinate the differences between procedures for taste and smell changes; a demographic and anthropometric analysis were also performed. Secondarily, the relation between food aversion and weight loss was also obtained.

RESULTS

Final analysis was based on 154 patients (104 LGBP and 50 LSG). The overall mean time between surgery and questionnaire was 10 ± 6.7 months. Most of the patients (87.6 %) experienced some taste/smell change. There were no differences between procedures for any change, taste or smell change. More patients submitted to LGBP referred that food smelled different (51.9 vs 34 % for the LSG group; p = 0.040). Higher %EWL was observed for patients presenting food aversion (73.3 ± 19.7 vs 65.8 ± 19.4 % for those without aversion; p = 0.046). Based on type of surgery, the LGBP group had the same trend (%EWL of 78.2 ± 17.3 vs 70.4 ± 18.6 % for those without aversion; p = 0.044).

CONCLUSION

The majority of patients presented taste and olfactory changes soon after surgery independently of type of procedure. Patients submitted to LGBP referred more often a different smell in food. Higher %EWL was observed in patients presenting any food aversion, especially in the LGBP group.

Total Weight Loss as the Outcome Measure of Choice After Roux-en-Y Gastric Bypass

BACKGROUND

Currently, there is no agreement on the best method to describe weight loss (WL) after bariatric surgery. The aim of this study is to evaluate short-term outcomes using percent of total body weight loss (%TWL).

METHODS

A single-institution retrospective study of 2420 patients undergoing Roux-en-Y gastric bypass (RYGB) was performed. Suboptimal WL was defined as %TWL < 20 % at 12 months.

RESULTS

Mean preoperative BMI was 46.8 ± 7.8 kg/m(2). One year after surgery, patients lost an average 14.1 kg/m(2) units of body mass index (BMI), 30.0 ± 8.5 %TWL, and 68.5 ± 22.9 %EWL. At 6 and 12 months after RYGB, mean BMI and percent excess WL (%EWL) significantly improved for all baseline BMI groups (p < 0.01, BMI; p = 0.01, %EWL), whereas mean %TWL was not significantly different among baseline BMI groups (p = 0.9). The regression analysis between each metric outcome and preoperative BMI demonstrated that preoperative BMI did not significantly correlate with %TWL at 1 year (r = 0.04, p = 0.3). On the contrary, preoperative BMI was strongly but negatively associated with the %EWL (r = -0.52, p < 0.01) and positively associated with the BMI units lost at 1 year (r = 0.56, p < 0.01). In total, 11.3 % of subjects achieved <20 %TWL at 12 months and were considered as suboptimal WL patients.

CONCLUSION

The results of our study confirm that %TWL should be the metric of choice when reporting WL because it is less influenced by preoperative BMI. Eleven percent of patients failed to achieve successful WL during the in the first year after RYGB based on our definition.

Weight Regain 10 Years After Roux-en-Y Gastric Bypass

OBJECTIVE

This study aims to investigate weight regain and the associated variables 10 years after Roux-en-Y gastric bypass.

METHOD

This retrospective study recruited patients submitted to Roux-en-Y gastric bypass (N = 166) for a 10-year follow-up. The following variables were investigated: body mass index (BMI), percentage of excess weight loss (%EWL), weight regain (WR), and percentage of weight regain (%WG). The chi-squared test or Fisher's exact test compared proportions, and the Mann-Whitney test compared numerical measurements between the groups. Analysis of variance (ANOVA) compared the measurements over time. The significance level was set at 5 %.

RESULTS

The sample had a mean age of 39.59 ± 11.69 years, and females prevailed (71.7 %). In the long-term follow-up, 41 % of the patients had weight regain. Seventy-two months after surgery, excess weight, preoperative BMI, gender, age, nutritional monitoring, and iron deficiency did not explain weight regain. Younger patients had regained significantly more weight 96 (p = 0.008) and 120 months (p = 0.004) after surgery than older patients. Patients who regained weight had ferritin <15 μg/dL 96 months after surgery (p = 0.019).

CONCLUSION

Patients submitted to Roux-en-Y gastric bypass presented weight regain, which increased over time. Age, iron deficiency, and time since surgery were associated with weight regain in the long-term follow-up.

Robotic platform for gastric bypass is associated with more resource utilization: an analysis of MBSAQIP dataset

BACKGROUND

The current literature comparing robot-assisted Roux-en-Y gastric bypass (RA-RYGB) and laparoscopic Roux-en-Y gastric bypass (LRYGB) is limited to single center retrospective series.

OBJECTIVES

This study aims to compare perioperative outcomes of patients who underwent RA-RYGB with those who underwent LRYGB.

SETTING

National database.

METHODS

Data on patients who underwent RA-RYGB and LRYGB were extracted from the 2015 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program participant use file. A 1:8 propensity score matching (RA-RYGB:LRYGB) was performed, and the 30-day outcomes of the propensity-matched cohorts were compared.

RESULTS

In total, 36,158 patients met inclusion criteria, including 2660 RA-RYGB (7.4%) cases, which were propensity matched (1:8) with 21,280 LRYGB cases having similar preoperative characteristics. RA-RYGB was associated with longer median operative time (136 versus 107 min; P<.001) and a higher 30-day readmission rate (7.3% versus 6.2%; P = .03). There were no statistical differences between the RA-RYGB and LRYGB cohorts with respect to all-cause morbidity (10.6% versus 10.7%; P = .8), serious morbidity (1.2% versus 1.7%; P = .07), mortality (0.1% versus .2%; P = .2), unplanned intensive care unit admission (1.1% versus 1.3%; P = .3), reoperation (2.4% versus 2.4%; P = .97), or reintervention (3.0% versus 2.5%; P = .2) within 30 days after surgery.

CONCLUSION

Based on available national data, RA-RYGB appears safe compared with a conventional laparoscopic approach for gastric bypass. However, RA-RYGB was associated with longer operative time and higher readmission rate, indicating greater resource use. Further studies are needed to better delineate the role of robotic platforms in bariatric surgery.

Predictors of Excess Weight Loss in Obese Patients After Gastric Bypass: a 60-Month Follow-up

BACKGROUND

The objective of this study was to analyze the factors associated with change in body mass index (BMI) and with percentage of excess weight loss (%EWL) in patients undergoing Roux-en-Y gastric bypass (RYGB). The following factors were analyzed: sex, age, surgical access (laparotomy vs. laparoscopy), preoperative BMI, waist circumference (WC), type 2 diabetes mellitus (T2DM), high blood pressure, and dyslipidemia.

METHODS

Retrospective cohort study using a convenience sample of 2070 patients of both sexes, aged 18 to 65 years, undergoing RYGB between 2000 and 2013. The outcomes of interest were BMI and %EWL at 0, 6, 12, 18, 24, 30, 36, 42, 48, 54, and 60 months after RYGB.

RESULTS

After 36, 48, and 60 months, approximately 50 % of patients had BMI >30 kg/m(2). As for %EWL, 60-month results were poor for 17 % of patients (%EWL <50 %), good for 40 % of patients (%EWL 50-75 %), very good for 24 % of patients (%EWL from >75-90 %), and excellent for 19 % of patients (%EWL >90 %). The four most significant predictors of BMI change 60 months after RYGB (in descending order of magnitude) were preoperative BMI, preoperative WC, surgical access, and age; and of %EWL, surgical access, preoperative BMI, preoperative WC, and age.

CONCLUSIONS

After 60 months of follow-up, the most relevant predictors of weight loss after RYGB were lower preoperative BMI and WC, videolaparoscopy as surgical access, and younger age. Further studies must be carried out to elucidate the impact of these factors on RYGB outcomes.

Exponential decay modeling can define parameters of weight loss trajectory after laparoscopic Roux-en-Y gastric bypass

BACKGROUND

Laparoscopic Roux-en-Y gastric bypass (LRYGB) produces durable and clinically significant weight loss. We aim to characterize the trajectory of weight loss, and demonstrate the predictive ability of three-month performance on final weight loss.

METHODS

Retrospective analysis of 1097 consecutive LRYGB patients allowed for assessment of conformity of various weight loss trajectory models. Establishing exponential decay as the optimal fit, initial, three-month and final BMI values were used to determine empiric rate constants (λ₃). Empirically derived weight loss curves and associated rate constants (λ) were generated.

RESULTS

Exponential decay optimally characterizes post-LRYGB weight loss trajectory. Final weight loss can be characterized by λ_3, as well as by the demographics black race (P = 0.008) and initial BMI (P < 0.001). Stratification by three-month weight loss allowed derivation of weight loss trajectory curves to predict weight at any point until and including plateau.

CONCLUSIONS

Weight loss after LRYGB conforms well to exponential decay, and postoperative trajectory can thus be predicted early. This allows the clinician early identification and intervention upon patients at risk of poor performance.

Maximizing Weight Loss After Roux-en-Y Gastric Bypass May Decrease Risk of Incident Organ Cancer

BACKGROUND

Recent studies have suggested that metabolic surgery reduces cancer risk. This study aims to determine if incident cancer is associated with the extent of weight loss after Roux-en-Y gastric bypass (RYGB).

METHODS

Patients at a large tertiary bariatric surgery center were retrospectively reviewed to identify patients with no history of cancer at the time of RYGB. Diagnoses in the electronic health record, a tumor registry, and chart review were used to identify postoperative incident solid organ cancer. The overall incidence of organ cancer was estimated using Kaplan-Meier analysis. The percent total body weight loss (%TWL) in the 48 months after surgery but prior to cancer was compared between those that developed organ cancer versus those that did not using repeated measures linear regression.

RESULTS

The 2943 patients had a mean age of 45.6 years (SD = 11.1), 81 % were female, and a mean baseline body mass index (BMI) of 47.2 kg/m² (SD = 7.9). Median follow-up after surgery was 3.8 years (range = [<1, 12]). Incident organ cancer developed and was verified in 54 of the 2943 patients (1.8 %). Kaplan-Meier estimates for cancer at 3, 5, and 10 years postsurgery were 1.3, 2.5, and 4.2 %. After adjusting for age, BMI, sex, diabetes, hypertension, and dyslipidemia, patients that developed organ cancer achieved less weight loss (-1.5 % TWL, 95 % CI = [-2.9 %, -0.1 %], p = 0.034).

CONCLUSIONS

Greater weight loss after metabolic surgery may be associated with lower organ cancer risk.

Mechanisms responsible for homeostatic appetite control: theoretical advances and practical implications

Homeostatic appetite control is part of a psychobiological system that has evolved to maintain an adequate supply of nutrients for growth and maintenance. The system links the physiological needs for energy with the behaviour that satisfies these needs (feeding), and is shaped by excitatory and inhibitory signals. Owing to rapid shifts in the food environment, homeostatic appetite control is not well adapted for modern-day human functioning. Areas covered: Homeostatic appetite control has two divisions. Tonic processes exert stable and enduring influences, with signals arising from bodily tissues and metabolism. Episodic processes fluctuate rapidly and are related to nutrient ingestion and the composition of foods consumed. Research in these areas incorporates potent endocrine signals that can influence behaviour. Expert commentary: The regulation of adipose tissue, and its impact on appetite (energy) homeostasis, has been heavily researched. More recently however, it has been demonstrated that fat-free mass has the potential to act as a tonic driver of food intake. A challenging issue is to determine how the post-prandial action of episodic satiety hormones and gastrointestinal mechanisms can effectively brake the metabolic drive to eat, in order to keep food intake under control and prevent a positive energy balance and fat accumulation.

Roux-En-Y Gastric Bypass Vs. Sleeve Gastrectomy: Balancing the Risks of Surgery with the Benefits of Weight Loss

Background

The purpose of the study was to compare weight loss, metabolic parameters, and postoperative complications in patients undergoing Roux-en-Y gastric bypass (GB) and sleeve gastrectomy (SG).

Methods

We retrospectively studied 30-day postoperative complications as well as change in weight, blood pressure, cholesterol, hemoglobin, hemoglobin A1C, and creatinine from baseline to 2, 6, 12, and 24 months postoperatively in 383 patients undergoing GB and 336 patients undergoing SG at the University of Michigan from January 2008 to November 2013. For a study population which typically has high attrition rates, there were excellent follow-up rates (706/719 at 2 months, 566/719 at 6 months, 519/719 at 12 months, and 382/719 at 24 months).

Results

Baseline characteristics were similar in both groups except for higher weight and BMI in the SG group. The GB group experienced greater total body weight loss at 6, 12, and 24 months (41.9 vs. 34.6 kg at 24 months, p < 0.0001). Excess weight loss was 69.7 and 51.7 % following GB and SG respectively at 24 months (p < 0.0001). BP improved significantly in both groups. Surgical complication rates were greater after GB (10.1 vs. 3.5 %, p = 0.0007) with no significant difference in life-threatening or potentially life-threatening complications.

Conclusions

Weight loss was greater following GB compared to SG at 2 years. The risk for surgical complications was greater following GB. Surgical intervention should be tailored to surgical risk, comorbidities, and desired weight loss.

Electronic supplementary material

The online version of this article (doi:10.1007/s11695-016-2265-2) contains supplementary material, which is available to authorized users.

Plasma amino acids, adiposity, and weight change after gastric bypass surgery: are amino acids associated with weight regain?

PURPOSE

Plasma concentrations of several amino acids (AAs) are positively correlated with obesity. The aim of this study was to examine if selected plasma AAs are associated with weight regain from 2 to 4 years after Roux-en-Y gastric bypass (RYGB).

METHODS

In a prospective study with 165 patients, we examined the relationship between plasma aromatic AAs (AAAs), branched chain AAs (BCAAs), and total cysteine (tCys) 2 years after RYGB, with BMI at 2 years and with weight change from 2 to 4 years after surgery. Analyses were adjusted for relevant covariates.

RESULT

The investigated AAs at 2 years correlated positively with BMI at 2 years (P ≤ 0.003 for all). BCAAs and AAAs at 2 years correlated inversely with % weight loss from 0 to 2 years (P = 0.002 and P = 0.001, respectively), while the association was not significant for tCys (r = -0.14, P = 0.08). Plasma tCys at 2 years correlated positively with BMI at 4 years (P = 0.010) and with weight regain from 2 to 4 years (P = 0.015).

CONCLUSION

Plasma AAAs, BCAAs, and tCys at 2 years were associated with BMI at 2 years. In addition, plasma AAAs and BCAAs at 2 years were associated with weight loss from 0 to 2 years, while tCys at 2 years was associated with weight regain from 2 to 4 years after RYGB. These results suggest that high tCys at 2 years may be used as a prognostic marker for future weight regain. The study was registered in ClinicalTrials.gov (NCT0 1270451).

Systematic review and retrospective validation of prediction models for weight loss after bariatric surgery

BACKGROUND

Patients often have less than realistic expectations of the weight loss they are likely to achieve after bariatric surgery. It would be useful to have a well-validated prediction tool that could give patients a realistic estimate of their expected weight loss.

OBJECTIVES

To perform a systematic review of the literature to identify existing prediction models and attempt to validate these models.

SETTING

University hospital, United Kingdom.

METHODS

A systematic review was performed. All English language studies were included if they used data to create a prediction model for postoperative weight loss after bariatric surgery. These models were then tested on patients undergoing bariatric surgery between January 1, 2013 and December 31, 2014 within our unit.

RESULTS

An initial literature search produced 446 results, of which only 4 were included in the final review. Our study population included 317 patients. Mean preoperative body mass index was 46.1 ± 7.1. For 257 (81.1%) patients, 12-month follow-up was available, and mean body mass index and percentage excess weight loss at 12 months was 33.0 ± 6.7 and 66.1% ± 23.7%, respectively. All 4 of the prediction models significantly overestimated the amount of weight loss achieved by patients. The best performing prediction model in our series produced a correlation coefficient (R²) of .61 and an area under the curve of .71 on receiver operating curve analysis.

CONCLUSIONS

All prediction models overestimated weight loss after bariatric surgery in our cohort. There is a need to develop better procedures and patient-specific models for better patient counselling.

Effect of patient-reported smoking status on short-term bariatric surgery outcomes

INTRODUCTION

Preoperative patient screening is a major contributor to the remarkable safety of bariatric surgery. Smoking status is a modifiable patient risk factor, and smoking cessation is associated with improved outcomes in surgical patients. However, the length of smoking cessation necessary to optimize bariatric surgery patient outcomes is not yet defined. We sought to explore the relationship between patient-reported smoking status and short-term bariatric surgery outcomes.

METHODS

Using prospectively collected data from the MBSC registry, we evaluated the effects of patient-reported length of tobacco abstinence on 30-day surgical outcomes. Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) patients (n = 49,772) were divided into three categories based on smoking status: never smoker, former smoker, and recent smoker. We compared risk-adjusted complication rates using multivariable logistic regression models and compared excess body weight loss using a one-way ANOVA test.

RESULTS

The risk-adjusted rate of severe complications among RYGB patients in the recent smoker group was significantly increased relative to patients who had never smoked (OR 1.34; 95% CI, 1.01-1.77), but not among SG patients (OR 1.18; 95% CI 0.87-1.62). In the same populations, differences in overall complication rate were not significant for either RYGB (OR, 1.11; 95% CI 0.94-1.31) or LSG (OR 1.04; 95% CI 0.86-1.25).

CONCLUSIONS

Recent smokers suffer detrimental effects of smoking on serious postoperative complications following RYGB surgery, but may not suffer an elevated risk of complications attributable to smoking for sleeve gastrectomy. An evaluation of the effect on long-term outcomes is necessary to further define the risks of smoking on bariatric surgery outcomes.

The FAT Score, a Fibrosis Score of Adipose Tissue: Predicting Weight-Loss Outcome After Gastric Bypass

CONTEXT

Bariatric surgery (BS) induces major and sustainable weight loss in many patients. Factors predicting poor weight-loss response (PR) need to be identified to improve patient care. Quantification of subcutaneous adipose tissue (scAT) fibrosis is negatively associated with post-BS weight loss, but whether it could constitute a predictor applicable in clinical routine remains to be demonstrated.

OBJECTIVE

To create a semiquantitative score evaluating scAT fibrosis and test its predictive value on weight-loss response after Roux-en-Y gastric bypass (RYGB).

METHODS

We created a fibrosis score of adipose tissue (FAT score) integrating perilobular and pericellular fibrosis. Using this score, we characterized 183 perioperative scAT biopsy specimens from severely obese patients who underwent RYGB (n = 85 from a training cohort; n = 98 from a confirmation cohort). PR to RYGB was defined as <28% of total weight loss at 1 year (lowest tertile). The link between FAT score and PR was tested in univariate and multivariate models.

RESULTS

FAT score was directly associated with increasing scAT fibrosis measured by a standard quantification method (P for trend <0.001). FAT score interobserver agreement was good (κ = 0.76). FAT score ≥2 was significantly associated with PR. The association remained significant after adjustment for age, diabetes status, hypertension, percent fat mass, and interleukin-6 level (adjusted odds ratio, 3.6; 95% confidence interval, 1.8 to 7.2; P = 0.003).

CONCLUSION

The FAT score is a new, simple, semiquantitative evaluation of human scAT fibrosis that may help identify patients with a potential limited weight-loss response to RYGB.

Using genetics to inform new therapeutics for diabetes

The genetic architecture of diabetes has been extensively studied. Numerous genetic markers for diabetes have been reported. However, the translation of such knowledge into clinical interventions has been inadequate. Areas covered: We performed a literature search on various frontiers in diabetes treatment that could be improved using genetic information: (1) understanding the mechanisms of existing antidiabetic drugs, (2) repurposing existing drugs for the treatment of diabetes, (3) complementing clinical trial findings; (4) finding novel treatment approaches; (5) better estimation of the efficacy of metabolic surgery. Expert commentary: The translation of genetic information to clinical intervention requires further study, including the development of an appropriate genetic risk score algorithm for type 2 diabetes. Genomic studies provide empirical explanations for clinical trial findings. Moreover, the mechanisms of antidiabetic drugs should be thoroughly investigated to enable clinical trials and pharmacogenomics studies of these drugs. As metabolic surgery becomes more prevalent for the treatment of diabetes, genetic approaches may improve patient prioritization.

Methods Employed to Assess Weight Loss in Older Adults by Means of Electronic Medical Records: A Systematic Review

Electronic medical records (EMRs) can be used to identify and categorize weight loss in older adults, but research has not scrutinized methods for doing so. Through a modified PRISMA protocol, we systematically reviewed published methods for quantifying weight change from EMRs. Articles (all available through July 2016) were identified through PubMed and SCOPUS searches, screened, and evaluated. We abstracted relevant data and tabulated the methods to assess weight change. The 13 selected articles showed little consistency in the approach to key methodological issues: 1) time ranges assessed; 2) removal of spurious values; 3) metrics to quantify weight change; 4) number of measures needed to estimate change; 5) threshold for significant weight change; and 6) relation to ideal weight. There was essentially no consensus around how to identify and categorize weight loss. Further investigation is needed to establish scientifically validated and clinically useful algorithms, accounting for the six issues above.

Patient Factors Predicting Weight Loss after Roux-en-Y Gastric Bypass

OBJECTIVE

The purpose of this study was to identify preoperative factors predicting weight loss following Roux-en-Y gastric bypass (RYGB) surgery.

MATERIAL AND METHODS

281 patients subjected to RYGB between January 2006 and June 2012 were included. Demographic, physical, and socioeconomic factors were assessed with regression analysis. Dependent variable was percent of excess weight loss (% EWL) at follow-up.

RESULTS

Follow-up data at one year was available in 96%, at two years in 88%, and at three years in 65% of the patients. Mean EWL was 72.5%. The success rate (defined as ≥60% EWL) at 1 year was 73% and at 2 years 74% and was 71% after 3 years. An earlier onset of obesity and high preoperative BMI were independently associated with unsuccessful weight loss at 1-year follow-up. At 2-year follow-up, an association between unsuccessful weight loss and psychiatric disorder, diabetes, hypertension, and preoperative BMI was seen. At 3-year follow-up no statistically significant associations were detected.

CONCLUSIONS

RYGB provides successful weight loss for most patients. The results from this study indicate that an earlier age of onset of obesity, high preoperative BMI, psychiatric disorder, diabetes, and hypertension are associated with unsuccessful weight loss.

The impact of bariatric surgery on inflammation: quenching the fire of obesity?

PURPOSE OF REVIEW

Numerous lines of evidence support the likelihood that inflammation drives the transition from obese/metabolically healthy to obese/type 2 diabetes (T2D). Given the temporal flexibility of inflammation in obesity-associated T2D, investigators have hypothesized that a precipitous drop in diabetogenic cytokines is critical for rapid 'T2D remission' following surgery but prior to significant weight loss. We review the evidence that changes in diabetogenic cytokines play a role in outcomes of bariatric surgery, including improved glycemic control.

RECENT FINDINGS

A 2016 indication for bariatric surgery to treat T2D integrates the large body of data showing rapid metabolic improvement. Parameters that account for improved glycemic control prior to significant weight loss, T2D recidivism over the long term, or failure of surgery to remit T2D in some patients are incompletely understood.

SUMMARY

We review the evidence that changes in diabetogenic cytokines play a role in outcomes of bariatric surgery, including improved glycemic control. We brainstorm future research directions that may improve surgical results.

Genetics of Bariatric Surgery Outcomes

Outcomes after bariatric surgery can vary widely and seem to have a significant genetic component. Only a small number of candidate gene and genome-wide association studies have analyzed bariatric surgery outcomes. The role of bile acids in mediating the beneficial effects of bariatric surgery implicate genes regulated by the farnesoid X receptor transcription factor.

Predictors of weight regain in patients who underwent Roux-en-Y gastric bypass surgery

BACKGROUND

Roux-en-Y gastric bypass (RYGB) is a highly effective treatment for obesity and results in long-term weight loss and resolution of co-morbidities. However, weight regain may occur as soon as 1-2 years after surgery.

OBJECTIVES

This retrospective study aimed to investigate the prevalence of weight regain and possible preoperative predictors of this phenomenon after RYGB.

SETTING

An academic medical center in the United States.

METHODS

A total of 1426 obese patients (15.8% male) who underwent RYGB during January 2000 to 2012 and had at least a 2-year follow-up were reviewed. We included only patients who were initially successful, having achieved at least 50% excess weight loss at 1 year postoperatively. Patients were then categorized into either the weight regain group (WR) or sustained weight loss (SWL) group based upon whether they gained≥15% of their 1-year postoperative weight.

RESULTS

Weight regain was observed in 244 patients (17.1%). Preoperative body mass index was similar between groups. Body mass index was significantly higher and percent excess weight loss was significantly lower in the WR group (P<.001). Average weight regain was 19.5±9.3 kg and-.8±8.5 in the WR and SWL groups, respectively (P<.001). Time elapsed since RYGB was significantly longer in the WR group (WR 6.0±2.4 years versus SWL 3.3±1.8 years; P<.001; range 2-12 yr). Patients in the WR group were significantly younger (WR 42.3±9.8 yr versus SWL 45.7±10.8 years; P<.001), had fewer co-morbidities, and were less likely to have type 2 diabetes with insulin dependence preoperatively. Univariate analysis found that older age, male gender, having hypertension, dyslipidemia, and insulin-treated type 2 diabetes were all factors associated with sustained weight loss. Moreover, a longer duration after RYGB was associated with weight regain. Multivariate analysis revealed that younger age was a significant predictor of weight regain even after adjusting for time since RYGB.

CONCLUSION

The present study confirmed that a longer interval after RYGB was associated with weight regain. Younger age was a significant predictor of weight regain even after adjusting for time since RYGB. The findings of this study underscore the complexity of the mechanisms underlying weight loss and regain after RYGB. Future prospective studies are needed to further explore the prevalence, predictors, and mechanisms of weight regain after RYGB.

Optimization of Vitamin D Status After Roux-en-Y Gastric Bypass Surgery in Obese Patients Living in Northern Climate

BACKGROUND

Patients who undergo bariatric surgery are at risk for micronutrient deficiencies. The aims of this study were to determine the prevalence and predictors of vitamin D deficiency in obese patients residing in the northern climate, and to evaluate the effectiveness of a daily maintenance dose of vitamin D 2000 IU in preventing hypovitaminosis D within 1 year after bariatric surgery.

METHODS

A cohort study involving adult patients undergoing RYGB was conducted. Longitudinal changes in serum vitamin D concentrations and clinical parameters were measured and collected.

RESULTS

Data from 134 recipients of RYGB were analyzed. Hypovitaminosis D was identified in 86 patients (64 %), and was significantly affected by seasonal change and the number of comorbidities. Follow-up data were available in 60 patients. Vitamin D sufficiency was achieved in 62.5 % of those patients with baseline vitamin D insufficiency. A dose-response relationship of vitamin D intake was observed, with the most significant increase in 25(OH)D associated with daily vitamin D intakes ≥ 2000 IU.

CONCLUSIONS

The prevalence of hypovitaminosis D before RYGB was comparable to patients living in the non-northern climate. Daily vitamin D intake meeting at least 2000 IU is associated with greater improvement in serum vitamin D concentration.

The Role of FTO and Vitamin D for the Weight Loss Effect of Roux-en-Y Gastric Bypass Surgery in Obese Patients

BACKGROUND

A recent study in children demonstrated that the rs9939609 single-nucleotide polymorphism in the fat mass and obesity (FTO) gene influences prospective weight gain, however, only in those who were vitamin D-deficient. If this might also be the case for Roux-en-Y gastric bypass (RYGB), surgery-induced weight loss is however unknown. The objective of this study is to examine if the magnitude of RYGB surgery-induced weight loss after 2 years depends on patients' FTO rs9939609 genotype (i.e., TT, AT, and AA) and presurgery vitamin D status (<50 nmol/L equals deficiency).

METHODS

Before and at 24 months after RYGB surgery, BMI was measured in 210 obese patients (mean BMI 45 kg/m(2), 72 % females). Serum 25-hydroxyvitamin D3 levels were also repeatedly measured. Following surgery, vitamin D was supplemented. Possible weight loss differences between genotypes were tested with multiple linear regressions.

RESULTS

The per-allele effect of each FTO A-allele on excessive BMI loss (EBMIL) was 3 % (P = 0.02). When split by baseline status, the EBMIL of vitamin D-deficient patients carrying AA exceeded that of vitamin D-deficient patients carrying TT by ~14 % (P = 0.03). No such genotypic differences were found in patients without presurgery vitamin D deficiency. Post-surgery serum levels of vitamin D did not differ between groups.

CONCLUSIONS

Our data suggest that presurgery vitamin D levels influence the size of genotype effects of FTO rs9939609 on RYGB surgery-induced weight loss in obese patients.

Risk of post-gastric bypass surgery hypoglycemia in nondiabetic individuals: A single center experience

OBJECTIVE

The epidemiology of post-gastric bypass surgery hypoglycemia (PGBH) is incompletely understood. This study aimed to evaluate the risk of PGBH among nondiabetic patients and associated factors.

METHODS

A cohort study of nondiabetic patients who underwent Roux-en-Y gastric bypass (RYGB) was conducted. PGBH was defined by any postoperative record of glucose < 60 mg/dL, diagnosis of hypoglycemia, or any medication use for treatment of PGBH. Kaplan-Meier analysis was used to describe PGBH occurrence, log-rank tests, and Cox regression to examine associated factors.

RESULTS

Of the 1,206 eligible patients, 86% were female with mean age of 43.7 years, mean preoperative BMI of 48.7 kg/m(2) , and a mean follow-up of 4.8 years. The cumulative incidence of hypoglycemia at 1 and 5 years post-RYGB was 2.7% and 13.3%, respectively. Incidence of PGBH was identified in 158 patients and was associated with lower preoperative BMI (P = 0.048), lower preoperative HbA1c (P = 0.012), and higher 6-month percent of excess body weight loss (%EWL) (P = 0.001). A lower preoperative HbA1c (HR = 1.73, P = 0.0034) and higher 6-month %EWL (HR = 1.96, P = 0.0074) remained independently correlated with increased risk for PGBH in multi-regression analysis.

CONCLUSIONS

The 5-year incidence of PGBH among nondiabetic individuals was 13.3% and was associated with a lower preoperative HbA1c and greater weight loss at 6 months following surgery.

Losing weight for a better health: Role for the gut microbiota

In recent years, there have been several reviews on gut microbiota, obesity and cardiometabolism summarizing interventions that may impact the gut microbiota and have beneficial effects on the host (some examples include [1–3]). In this review we discuss how the gut microbiota changes with weight loss (WL) interventions in relation to clinical and dietary parameters. We also evaluate available evidence on the heterogeneity of response to these interventions. Two important questions were generated in this regard: 1) Can response to an intervention be predicted? 2) Could pre-intervention modifications to the gut microbiota optimize WL and metabolic improvement? Finally, we have delineated some recommendations for future research, such as the importance of assessment of diet and other environmental exposures in WL intervention studies, and the need to shift to more integrative approaches of data analysis.

Predictors of Lowest Weight and Long-Term Weight Regain Among Roux-en-Y Gastric Bypass Patients

BACKGROUND

Weight loss surgery (WLS) outcomes are poorly understood. This study aimed to evaluate the relationship of well-documented (e.g., health, diet, physical activity) and theoretically relevant variables (e.g., substance use and "food addiction") with both weight nadir and weight regain (WR) following WLS.

METHODS

A sample of 97 Roux-en-Y gastric bypass patients (M time since surgery = 8.86 years) were surveyed about pre- and post-WLS weight, health, self-management behaviors, alcohol problems, and clinical symptoms.

RESULTS

Patients lost a mean of 42 % (SD = 10.71 %) of total weight at weight nadir, but 26 % (SD = 19.66 %) of the lost weight was regained by the time of the survey. Correlates of lower weight nadir and WR differed considerably, with minor overlap. Weight nadir was associated with pre-WLS drug use and post-WLS medical comorbidities. WR, on the other hand, was associated with post-WLS adherence to dietary and physical activity modification. Post-WLS nocturnal eating, depression, and problematic alcohol use were also associated with WR. With all associated variables in regression models, number of post-WLS medical comorbidities (β = -.313, p < 0.01) and post-WLS depression (β = 0.325, p < 0.01) accounted for the most variance and remained as significant predictors of weight nadir and WR, respectively.

CONCLUSIONS

While weight nadir was associated with relatively few and largely nonmodifiable variables, WR was significantly associated with adherence-related behaviors, mood symptoms, and pathological patterns of food and alcohol use, all of which are potentially modifiable. These findings underscore the importance of long-term behavioral and psychosocial monitoring after surgery.

Red cell distribution width is a novel biomarker that predicts excess body-mass index loss 1 year after laparoscopic Roux-en-Y gastric bypass

INTRODUCTION

Bariatric surgery is the most effective method for producing sustained weight loss, improving obesity-associated comorbidities and reducing inflammation in the morbidly obese population. The red cell distribution width (RDW) is a novel marker of inflammation that is usually reported as part of a complete blood count. In this study, we tested our hypothesis that red cell distribution width might represent a novel biomarker predictive of excess body-mass index loss (EBMIL) following laparoscopic Roux-en-Y gastric bypass (LRYGB).

METHODS

Five hundred and forty-seven LRYGB patients included from a single institution were individually reviewed, noting both preoperative RDW and percent excess BMI loss at 6 months and 1 year post-LRYGB (%EBMIL180 and %EBMIL365, respectively). Bivariate and multivariate linear regression analysis was conducted between age, gender, initial body-mass index (BMI0) and RDW and each of the two endpoints, to assess the independence of RDW as a predictor of postoperative success.

RESULTS

The median RDW was 13.9 (13.3-14.6) %, and median EBMIL180 and EBMIL365 were 55.4 (45.2-66.7) % and 71.3 (58.9-87.8) %, respectively. After controlling for age, gender and BMI0, RDW was associated with %EBMIL365 (B = -1.4 [-2.8 to -0.002] %, P = .05), but not %EBMIL180 (B = -0.6 [-1.6 to 0.5] %, P = .30. Upon Kruskal-Wallis analysis, patients with a preoperative RDW > 15.0 % had significantly lower %EBMIL than those in the <13.0 % (P < .001) and 13.0-15.0 % (P < .01) strata.

CONCLUSIONS

RDW is predictive of EBMIL at 1 year following LRYGB. This represents a novel preoperative biomarker that may provide clinically useful prognostic information.

Prediction of excess weight loss after laparoscopic Roux-en-Y gastric bypass: data from an artificial neural network

INTRODUCTION

Laparoscopic Roux-en-Y gastric bypass (LRYGB) has become the gold standard for surgical weight loss. The success of LRYGB may be measured by excess body mass index loss (%EBMIL) over 25 kg/m(2), which is partially determined by multiple patient factors. In this study, artificial neural network (ANN) modeling was used to derive a reasonable estimate of expected postoperative weight loss using only known preoperative patient variables. Additionally, ANN modeling allowed for the discriminant prediction of achievement of benchmark 50% EBMIL at 1 year postoperatively.

METHODS

Six hundred and forty-seven LRYGB included patients were retrospectively reviewed for preoperative factors independently associated with EBMIL at 180 and 365 days postoperatively (EBMIL180 and EBMIL365, respectively). Previously validated factors were selectively analyzed, including age; race; gender; preoperative BMI (BMI0); hemoglobin; and diagnoses of hypertension (HTN), diabetes mellitus (DM), and depression or anxiety disorder. Variables significant upon multivariate analysis (P < .05) were modeled by "traditional" multiple linear regression and an ANN, to predict %EBMIL180 and %EBMIL365.

RESULTS

The mean EBMIL180 and EBMIL365 were 56.4 ± 16.5 % and 73.5 ± 21.5%, corresponding to total body weight losses of 25.7 ± 5.9% and 33.6 ± 8.0%, respectively. Upon multivariate analysis, independent factors associated with EBMIL180 included black race (B = -6.3%, P < .001), BMI0 (B = -1.1%/unit BMI, P < .001), and DM (B = -3.2%, P < .004). For EBMIL365, independently associated factors were female gender (B = 6.4%, P < .001), black race (B = -6.7%, P < .001), BMI0 (B = -1.2%/unit BMI, P < .001), HTN (B = -3.7%, P = .03), and DM (B = -6.0%, P < .001). Pearson r(2) values for the multiple linear regression and ANN models were 0.38 (EBMIL180) and 0.35 (EBMIL365), and 0.42 (EBMIL180) and 0.38 (EBMIL365), respectively. ANN prediction of benchmark 50% EBMIL at 365 days generated an area under the curve of 0.78 ± 0.03 in the training set (n = 518) and 0.83 ± 0.04 (n = 129) in the validation set.

CONCLUSIONS

Available at https://redcap.vanderbilt.edu/surveys/?s=3HCR43AKXR, this or other ANN models may be used to provide an optimized estimate of postoperative EBMIL following LRYGB.

Impaired weight loss in laparoscopic adjustable gastric banding patients over 50 years of age: diabetes mellitus as an independent risk factor

INTRODUCTION

Laparoscopic adjustable gastric banding (LAGB) represents a safe and effective bariatric procedure, particularly for patients over 50. Preoperative risk factors for impaired post-LAGB excess weight loss are not well characterized for this population. This study aimed to identify demographics, characteristics or comorbidities associated with excess weight loss at 6 and 12 months postoperatively (EWL180 and EWL365, respectively) for these patients.

METHODS

One hundred and seventeen LAGB patients >50 years of age from 2005 to 2014 were retrospectively reviewed for factors potentially associated with EWL180 and EWL365. Rationally selected variables chosen for analysis included age, race, gender, initial body mass index and preoperative weight loss; comorbidities assessed included hypertension, psychiatric disorders and diabetes mellitus (DM). Variables correlated with EWL180 or EWL365 on bivariate linear regression analysis (P ≤ .05) were input into multivariate linear regression analysis to confirm independent association.

RESULTS

Preoperative DM (B = -9.1% EWL; 95% CI -13.6, -4.5%; P < .001) and African-American race (B = -8.8% EWL; 95% CI -17.3, -0.3%; P = .05) were independent risk factors for impaired EWL180. Only DM was a risk factor for impaired EWL365 (B = -9.7% EWL; 95% CI -17.7, -1.8%; P = .02).

CONCLUSIONS

LAGB is a successful operation in patients >50 years of age. Preoperative DM is an independent risk factor for impaired EWL in this cohort.

Vitamin D status and supplementation before and after bariatric surgery: a comprehensive literature review

BACKGROUND

Bariatric surgery is the most effective long-term weight loss method. The most common procedures are Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG). Bariatric patients are at high risk of vitamin D deficiency (VDD) and insufficiency (VDI), which are associated with skeletal and nonskeletal ailments. There is no consensus regarding the optimal treatment for VDD/VDI in bariatric patients.

OBJECTIVES

To critically examine the literature on vitamin D status (serum 25[OH]D concentrations) pre- and postbariatric surgery as well as supplementation regimens currently used.

METHODS

We searched PubMed, Embase, and Cochrane from inception to May 2015 for articles relating to vitamin D, RYGB, and VSG. Of 208 citations retrieved, 30 were included.

RESULTS

Preoperative VDD (<20 ng/mL) ranged from 13% to 90%, while VDI (<30 ng/mL) was found in up to 98%. Prevalence remained similar postoperatively and was highest after RYGB. Most studies found dosages<800 IU daily insufficient postbariatric surgery. Other studies examined the effectiveness of dosages between 1000 and 5000 IU daily, reaching similar conclusions. Several studies suggested using 50,000 IU weekly plus a daily dose. No studies reported optimization.

CONCLUSIONS

It is widely accepted that serum 25(OH)D concentrations above 30 ng/mL are optimal; however, current postbariatric vitamin D supplementation fails to raise 25(OH)D above that level universally. This review highlights both the great need and the lack of consensus on the optimal supplementation regimen (dosage and frequency) for pre- and postbariatric patients. Future studies should investigate multiple regimens and attempt to identify methods for personalizing these regimens if found necessary.

RYGB progressively increases avidity for a low-energy, artificially sweetened diet in female rats

Weight re-gain within 2 y after Roux-en-Y gastric bypass (RYGB) is significantly associated with increased intake of and cravings for sweet foods. Here we describe a novel model of this late increase in sweet appetite. Ovariectomized RYGB and Sham-operated rats, with or without estradiol treatment, were maintained on Ensure liquid diet and offered a low-energy, artificially sweetened diet (ASD) 2 h/d. First, we tested rats more than six months after RYGB. ASD meals were larger in RYGB than Sham rats, whereas Ensure meals were smaller. General physical activity increased during ASD meals in RYGB rats, but not during Ensure meals. Second, new rats were adapted to ASD before surgery, and were then offered ASD again during 4-10 wk following surgery. Estradiol-treated RYGB rats lost the most weight and progressively increased ASD intake to >20 g/2 h in wk 9-10 vs. ∼3 g/2 h in Sham rats. Finally, the same rats were then treated with leptin or saline for 8 d. Leptin did not affect body weight, Ensure intake, or activity during meals, but slightly reduced ASD intake in estradiol-treated RYGB rats. Food-anticipatory activity was increased in estradiol-treated RYGB rats during the saline-injection tests. Because increased meal-related physical activity together with larger meals is evidence of hunger in rats, these data suggest that (1) RYGB can increase hunger for a low-energy sweet food in rats and (2) low leptin levels contribute to this hunger, but are not its only cause. This provides a unique rat model for the increased avidity for sweets that is significantly associated with weight recidivism late after RYGB.

Bariatric Surgery in the United Kingdom: A Cohort Study of Weight Loss and Clinical Outcomes in Routine Clinical Care

BACKGROUND

Bariatric surgery is becoming a more widespread treatment for obesity. Comprehensive evidence of the long-term effects of contemporary surgery on a broad range of clinical outcomes in large populations treated in routine clinical practice is lacking. The objective of this study was to measure the association between bariatric surgery, weight, body mass index, and obesity-related co-morbidities.

METHODS AND FINDINGS

This was an observational retrospective cohort study using data from the United Kingdom Clinical Practice Research Datalink. All 3,882 patients registered in the database and with bariatric surgery on or before 31 December 2014 were included and matched by propensity score to 3,882 obese patients without surgery. The main outcome measures were change in weight and body mass index over 4 y; incident diagnoses of type 2 diabetes mellitus (T2DM), hypertension, angina, myocardial infarction (MI), stroke, fractures, obstructive sleep apnoea, and cancer; mortality; and resolution of hypertension and T2DM. Weight measures were available for 3,847 patients between 1 and 4 mo, 2,884 patients between 5 and 12 mo, and 2,258 patients between 13 and 48 mo post-procedure. Bariatric surgery patients exhibited rapid weight loss for the first four postoperative months, at a rate of 4.98 kg/mo (95% CI 4.88-5.08). Slower weight loss was sustained to the end of 4 y. Gastric bypass (6.56 kg/mo) and sleeve gastrectomy (6.29 kg/mo) were associated with greater initial weight reduction than gastric banding (2.77 kg/mo). Protective hazard ratios (HRs) were detected for bariatric surgery for incident T2DM, 0.68 (95% CI 0.55-0.83); hypertension, 0.35 (95% CI 0.27-0.45); angina, 0.59 (95% CI 0.40-0.87);MI, 0.28 (95% CI 0.10-0.74); and obstructive sleep apnoea, 0.55 (95% CI 0.40-0.87). Strong associations were found between bariatric surgery and the resolution of T2DM, with a HR of 9.29 (95% CI 6.84-12.62), and between bariatric surgery and the resolution of hypertension, with a HR of 5.64 (95% CI 2.65-11.99). No association was detected between bariatric surgery and fractures, cancer, or stroke. Effect estimates for mortality found no protective association with bariatric surgery overall, with a HR of 0.97 (95% CI 0.66-1.43). The data used were recorded for the management of patients in primary care and may be subject to inaccuracy, which would tend to lead to underestimates of true relative effect sizes.

CONCLUSIONS

Bariatric surgery as delivered in the UK healthcare system is associated with dramatic weight loss, sustained at least 4 y after surgery. This weight loss is accompanied by substantial improvements in pre-existing T2DM and hypertension, as well as a reduced risk of incident T2DM, hypertension, angina, MI, and obstructive sleep apnoea. Widening the availability of bariatric surgery could lead to substantial health benefits for many people who are morbidly obese.

The effect of insurance status on pre- and post-operative bariatric surgery outcomes

BACKGROUND

This study compared pre- and post-surgical data and outcomes among gastric bypass patients based on the type of insurance (Medicaid, Medicare, or private).

METHODS

Data were examined from 2553 consecutive RYGB patients at a rural ASMBS Center of Excellence.

RESULTS

Participants were primarily female (80.5 %), Caucasian (97.1 %), and middle-aged (45.9 years). Medicaid patients' BMI at consultation was significantly higher than the other two groups (p < 0.001). Time to surgery was significantly longer for Medicaid (13.2 %) and Medicare (7.1 %) patients compared with privately insured patients (p < 0.001). Pre-surgical weight loss and post-surgical percent of excess weight loss nadir did not differ among the groups. Type 2 diabetes remission rates were comparable across insurance groups.

CONCLUSIONS

Medicaid patients, although demographically different from their privately insured and Medicare counterparts, will benefit from surgery with comparable weight loss results and overall diabetes remission rates.

Factors Associated With Long-Term Weight Loss Following Bariatric Surgery Using 2 Methods for Repeated Measures Analysis

We used electronic health record data from 162 patients enrolled in the NUgene Project (2002-2013) to determine demographic factors associated with long-term (from 1 to up to 9.5 (mean = 5.6) years) weight loss following Roux-en-Y gastric bypass surgery. Ninety-nine (61.1%) patients self-reported white, and 63 (38.9%) self-reported black, mixed, or missing race. The average percent weight loss was -33.4% (standard deviation, 9.3) at 1 year after surgery and -30.7% (standard deviation, 12.5) at the last follow-up point. We used linear mixed and semiparametric trajectory models to test the association of surgical and demographic factors (height, surgery age, surgery weight, surgery body mass index, marital status, sex, educational level, site, International Classification of Diseases code, Current Procedural Terminology code, Hispanic ethnicity, and self-reported race) with long-term percent weight loss and pattern of weight loss. We found that black, mixed, and missing races (combined) in comparison with white race were associated with a decreased percent weight loss of -4.31% (95% confidence interval: -7.30, -1.32) and were less likely to have higher and sustained percent weight loss (P = 0.04). We also found that less obese patients were less likely to have higher and sustained percent weight loss (P = 0.01). These findings may be helpful to patients in setting expectations after weight loss surgery.