Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient--2013 update: cosponsored by American Association of Clinical Endocrinologists, the Obesity Society, and American Society for Metabolic & Bariatric Surgery

Early postoperative weight loss predicts maximal weight loss after sleeve gastrectomy and Roux-en-Y gastric bypass

Background

Previous studies show that ‘poor responders’ to Roux-en-Y gastric bypass (RYGBP) may be identified on the basis of early postoperative weight loss. Early identification of poor responders could allow earlier provision of postoperative behavioural and/or intensive lifestyle interventions and enhance their maximal weight loss. Our aim was to investigate whether early postoperative weight loss predicts the maximal weight loss response after RYGBP and sleeve gastrectomy (SG).

Methods

We undertook a retrospective cross-sectional study of 1,456 adults who underwent either RYGBP (n = 918) or SG (n = 538) as a primary procedure in one of two European centres. Postoperative weight loss was expressed as weight loss velocity (WLV) and percentage weight loss. Linear regression analyses were performed to determine the association of early postoperative weight loss with maximal %WL, including adjustment for baseline variables.

Results

There was marked variability in maximal %WL following both RYGBP (mean 32.9 %, range 4.1–60.9 %) and SG (mean 26.2 %, range 1.1–58.3 %). WLV 3–6 months postoperatively was more strongly associated with maximal %WL (r² = 0.32 for RYGBP and r² = 0.26 for SG, P < 0.001 for both) than either WLV 0–6 weeks or 6 weeks to 3 months postoperatively (r² = 0.14 and 0.10 for RYGBP, respectively; r² = 0.18 and 0.21 for SG, respectively; P < 0.001 for all). Multiple linear regression analysis, including baseline variables of age, sex, preoperative BMI, type 2 diabetes, ethnicity, and bariatric centre, revealed that 3–6 month WLV was an independent predictor of maximal %WL in both SG and RYGBP groups (standardised β-coefficients 0.51 and 0.52, respectively; P < 0.001 for both).

Conclusions

There is a marked variability in weight loss response following RYGBP and SG. Early postoperative weight loss can be used to identify patients whose predicted weight loss trajectories are suboptimal. Early targeting of poor responders with more intensive postoperative lifestyle and behavioural support could potentially enhance their weight loss response.

Psychiatric aspects of bariatric surgery

PURPOSE OF REVIEW

Bariatric surgery has been consistently shown to be effective in long-term marked weight loss and in bringing significant improvement to medical comorbidities such as metabolic syndrome. Empirical data suggest a high prevalence of psychiatric disorders among bariatric surgery candidates. In this review, we focus on the studies published recently with a high impact on our understanding of the role of psychiatry in bariatric surgery.

RECENT FINDINGS

This article reviews the specific psychopathologies before surgery, changes in psychopathologies after surgery, suicide risk related to bariatric surgery, factors associated with weight loss, and recommendations for presurgical and postsurgical assessment and management. Research indicates a decrease in certain psychiatric symptoms after weight loss with bariatric surgery. However, the risk of suicide and unsuccessful weight loss in some bariatric surgery patients make monitoring following surgery as important as careful assessment and management before surgery. Specific considerations for youth and older populations and future potential research foci are discussed.

SUMMARY

Recent publications suggest new directions for psychiatric evaluation and interventions for bariatric surgery patients. Future research on outcomes of specific populations, effectiveness of psychopharmacotherapy, and underlying pathophysiology are warranted for the advancement of treating bariatric surgery patients.

Relationship between gut hormones and glucose homeostasis after bariatric surgery

Type 2 diabetes mellitus (T2D) is emerging as a worldwide public health problem, and is mainly associated with an increased incidence of obesity. Bariatric surgery is currently considered the most effective treatment for severely obese patients. After bariatric surgery, T2D patients have shown a significant improvement in glycemic control, even before substantial weight loss and often discontinuation of medication for diabetes control. A central role for enteroendocrine cells from the epithelium of the gastrointestinal tract has been speculated in this postoperative phenomenon. These cells produce and secrete polypeptides - gut hormones - that are associated with regulating energy intake and glucose homeostasis through modulation of peripheral target organs, including the endocrine pancreas. This article reviews and discusses the biological actions of the gut hormones ghrelin, cholecystokinin, incretins, enteroglucagon, and Peptide YY, all of which were recently identified as potential candidates for mediators of glycemic control after bariatric surgery. In conclusion, current data reinforce the hypothesis that T2D reversion after bariatric surgery may be related to glycemic homeostasis developed by the intestine.

Malnutrition in pregnancy following bariatric surgery: three clinical cases of fetal neural defects

Objective

Bariatric surgery results in decreased food intake and a variable degree of malabsorption. Without adequate supplementation, the most common complications of this surgery are nutritional disorders. Pregnancy following surgery for obesity is a particular condition requiring strict monitoring of nutrient intake necessary for fetal development and a favourable neonatal prognosis.

Patients

Malnutrition in pregnancy and congenital neural malformations are reported in three women who had previously undergone bariatric surgery (1, 5 and 18 years before pregnancy, respectively). Two patients underwent the Roux en Y bypass and one bilio-pancreatic diversion with gastroplasty. None of the three received pre-conceptional nutritional counselling. Patients 1 and 2 did not undergo postoperative nutritional surveillance; nutrient supplementation was started at 22 and 20 weeks gestation, respectively. In patient 3, supplementation was stopped at six weeks gestation.

Results

Newborns 1 and 2 presented with dorsal myelomeningocele and ventricular dilation. Both underwent surgery and a ventriculo-peritoneal shunt was inserted in the first month of life. Newborn 3 had microcephaly, bilateral microphthalmia and sensorineural deafness.

Conclusions

Diet and nutritional status, before and during pregnancy, play an important role in the early processes of fetal development and neonatal outcome. Women of childbearing age who have had bariatric surgery, should be encouraged to follow a well-balanced diet as part of a weight management strategy. They should be advised to take recommended maternal supplements.

Neuropsychological factors and bariatric surgery: a review

Obesity has become a global epidemic with associated physical, psychological, and cognitive deficits that tax the healthcare system and result in a significant economic burden. These costs have necessitated treatment measures to reduce the incidence of obesity as well as comorbidities associated with obesity. We review the current literature in order to describe the pre-surgical psychological and cognitive characteristics of individuals undergoing bariatric surgery and the possible changes in these functions following surgery. We discuss the importance of a pre-surgical evaluation that adequately evaluates cognitive and emotional functioning and what this evaluation should entail. Finally, we discuss recent trends in the types of bariatric surgeries being performed and how these changes may influence subsequent physical, cognitive, and emotional health.

Bariatric surgery versus intensive medical therapy for diabetes--3-year outcomes

BACKGROUND

In short-term randomized trials (duration, 1 to 2 years), bariatric surgery has been associated with improvement in type 2 diabetes mellitus.

METHODS

We assessed outcomes 3 years after the randomization of 150 obese patients with uncontrolled type 2 diabetes to receive either intensive medical therapy alone or intensive medical therapy plus Roux-en-Y gastric bypass or sleeve gastrectomy. The primary end point was a glycated hemoglobin level of 6.0% or less.

RESULTS

The mean (±SD) age of the patients at baseline was 48±8 years, 68% were women, the mean baseline glycated hemoglobin level was 9.3±1.5%, and the mean baseline body-mass index (the weight in kilograms divided by the square of the height in meters) was 36.0±3.5. A total of 91% of the patients completed 36 months of follow-up. At 3 years, the criterion for the primary end point was met by 5% of the patients in the medical-therapy group, as compared with 38% of those in the gastric-bypass group (P<0.001) and 24% of those in the sleeve-gastrectomy group (P=0.01). The use of glucose-lowering medications, including insulin, was lower in the surgical groups than in the medical-therapy group. Patients in the surgical groups had greater mean percentage reductions in weight from baseline, with reductions of 24.5±9.1% in the gastric-bypass group and 21.1±8.9% in the sleeve-gastrectomy group, as compared with a reduction of 4.2±8.3% in the medical-therapy group (P<0.001 for both comparisons). Quality-of-life measures were significantly better in the two surgical groups than in the medical-therapy group. There were no major late surgical complications.

CONCLUSIONS

Among obese patients with uncontrolled type 2 diabetes, 3 years of intensive medical therapy plus bariatric surgery resulted in glycemic control in significantly more patients than did medical therapy alone. Analyses of secondary end points, including body weight, use of glucose-lowering medications, and quality of life, also showed favorable results at 3 years in the surgical groups, as compared with the group receiving medical therapy alone. (Funded by Ethicon and others; STAMPEDE ClinicalTrials.gov number, NCT00432809.).

Bariatric endocrinology: principles of medical practice

Obesity, is a chronic, biological, preventable, and treatable disease. The accumulation of fat mass causes physical changes (adiposity), metabolic and hormonal changes due to adipose tissue dysfunction (adiposopathy), and psychological changes. Bariatric endocrinology was conceived from the need to address the neuro-endocrinological derangements that are associated with adiposopathy, and from the need to broaden the scope of the management of its complications. In addition to the well-established metabolic complications of overweight and obesity, adiposopathy leads to hyperinsulinemia, hyperleptinemia, hypoadiponectinemia, dysregulation of gut peptides including GLP-1 and ghrelin, the development of an inflammatory milieu, and the strong risk of vascular disease. Therapy for adiposopathy hinges on effectively lowering the ratio of orexigenic to anorexigenic signals reaching the the hypothalamus and other relevant brain regions, favoring a lower caloric intake. Adiposopathy, overweight and obesity should be treated indefinitely with the specific aims to reduce fat mass for the adiposity complications, and to normalize adipose tissue function for the adiposopathic complications. This paper defines the principles of medical practice in bariatric endocrinology-the treatment of overweight and obesity as means to treat adiposopathy and its accompanying metabolic and hormonal derangements.

Measurement of disordered eating in bariatric surgery candidates: a systematic review of the literature

Symptoms of disordered eating are common among patients seeking bariatric surgery, and assessment of eating pathology is typical in pre-surgical evaluations. A systematic review was conducted to evaluate the definitions, diagnostic criteria and measures used to assess disordered eating in adults seeking bariatric surgery. The review identified 147 articles featuring 34 questionnaires and 45 interviews used in pre-surgical assessments. The Questionnaire on Eating and Weight Patterns Revised and the Structured Clinical Interview for DSM were the most frequently used questionnaire and interview respectively. Variations to pre-surgical diagnostic criteria included changes to the frequency and duration criteria for binge eating, and inconsistent use of disordered eating definitions (e.g., grazing). Results demonstrate a paucity of measures designed specifically for an obese sample, and only 24% of questionnaires and 4% of interviews used had any reported psychometric evaluation in bariatric surgery candidates. The psychometric data available suggest that interview assessments are critical for accurately identifying binge episodes and other diagnostic information, while self-report questionnaires may be valuable for providing additional information of clinical utility (e.g., severity of eating, shape and weight-related concerns). Findings highlight the need for consensus on disordered eating diagnostic criteria and psychometric evaluation of measures to determine whether existing measures provide a valid assessment of disordered eating in this population. Consistent diagnosis and the use of validated measures will facilitate accurate identification of disordered eating in the pre-surgical population to enable assessment of suitability for surgery and appropriate targeting of treatment for disordered eating to optimise treatment success.

Bone loss after bariatric surgery: causes, consequences, and management

Bariatric surgery is an effective and increasingly common treatment for severe obesity and its many comorbidities. The side-effects of bariatric surgery can include detrimental effects on bone and mineral metabolism. Bone disease in patients who have had bariatric surgery is affected by preoperative abnormalities in bone and mineral metabolism related to severe obesity. Changes that arise after bariatric surgery are specific to procedure type: the most pronounced abnormalities in calciotropic hormones and bone loss are noted after procedures that result in the most malabsorption. The most consistent site for bone loss after all bariatric procedures is at the hip. There are limitations of dual-energy x-ray absorptiometry technology in this population, including artefact introduced by adipose tissue itself. Bone loss after bariatric surgery is probably multifactorial. Proposed mechanisms include skeletal unloading, abnormalities in calciotropic hormones, and changes in gut hormones. Few data for fracture risk in the bariatric population are available, and this is a crucial area for additional research. Treatment should be geared toward correction of nutritional deficiencies and study of bone mineral density in high-risk patients. We explore the skeletal response to bariatric surgery, potential mechanisms for changes, and strategies for management.

Frequency of laboratory testing among gastric bypass patients

BACKGROUND

Long-term laboratory monitoring is recommended after gastric bypass surgery to prevent the development of micronutrient deficiencies. The objective of this study was to characterize patterns of laboratory monitoring after surgery.

METHODS

We used a large insurance claims database to assess the frequency of laboratory testing after gastric bypass surgery. We assessed the tests recommended by an expert panel on bariatric surgery, including tests recommended routinely as well as second-line tests for specific clinical scenarios (e.g., tests for anemia when iron deficiency is not present).

RESULTS

With the exception of testing for diabetes, most gastric bypass patients did not undergo routine laboratory testing in the first year after their surgery, ranging from 54% (electrolytes) to 95% (zinc). However, for first-line tests, significantly more gastric bypass patients underwent testing in the first year,compared with gastric banding patients. Differences in testing frequency between gastric bypass and gastric banding patients were larger for tests of micronutrient deficiency than for common metabolic panels and complete blood counts. For second-line tests, much smaller percentages of both groups of patients underwent testing, either in the first year or after year 1.

CONCLUSION

Patients undergoing gastric bypass do not routinely undergo recommended laboratory tests, although they are undergoing more monitoring than gastric banding patients. Efforts must be made by patients, surgeons, and primary care providers to ensure that routine testing is done to lower the risk of adverse health outcomes.

Anemia, iron and vitamin B12 deficiencies after sleeve gastrectomy compared to Roux-en-Y gastric bypass: a meta-analysis

BACKGROUND

The effective treatment of postoperative anemia and nutritional deficiencies is critical for the successful management of bariatric patients. However, the evidence for nutritional risk or support of bariatric patients remains scarce. The aims of this study were to assess current evidence of the association between 2 methods of bariatric surgery, sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB), and postoperative anemia and nutritional deficiencies.

METHODS

MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were searched for English-language studies using a list of keywords. Reference lists from relevant review articles were also searched. In the authors' meta-analysis, they included studies with a duration of>12 months, those comparing SG with RYGB, and those with available outcome data for postoperative anemia and iron and vitamin B12 deficiencies. Of 36 potentially relevant studies, 9 met the inclusion criteria. Data were combined by means of a fixed-effects model or random-effects model.

RESULTS

Compared with the SG group, the odds ratio for postoperative vitamin B12 deficiency in the RYGB group was 3.55 (95% confidence interval, 1.26-10.01; P<.001). In the subgroup analysis, studies in which prophylactic iron or vitamin B12 was administered lost significance in the odds ratio for postoperative vitamin B12 deficiency.

CONCLUSION

The authors' findings suggest that SG is more beneficial than RYGB with regard to postoperative vitamin B12 deficiency risk, whereas the 2 methods are comparable with regard to the risk of postoperative anemia and iron deficiency. Postoperative prophylactic iron and B12 supplementation, in addition to general multivitamin and mineral supplementation, is recommended based on the comparable deficiency risk of the 2 methods as indicated by subgroup analysis.

Dosing of enoxaparin for venous thromboembolism prophylaxis in obese patients

OBJECTIVE

To evaluate the appropriate dosing of enoxaparin as a venous thromboembolism (VTE) prophylaxis in hospitalized obese patients.

DATA SOURCES

Literature articles were accessed through MEDLINE (1946 to August week 1, 2013) and EMBASE (1980 to 2013 week 33) searches using the terms enoxaparin, obesity, and thromboprophylaxis.

STUDY SELECTION AND DATA EXTRACTION

All articles that involved human subjects and were published in the English language, evaluating the appropriate dose of enoxaparin for VTE prophylaxis in hospitalized, obese patients were included.

DATA SYNTHESIS

Appropriate enoxaparin dosing for thromboprophylaxis in adult patients is 40 mg subcutaneously daily or 30 mg subcutaneously twice daily. Although obesity is considered one of the risk factors for thromboembolism, morbidly obese patients were excluded from most clinical trials; therefore, the appropriate enoxaparin preventive dose is not clear in this population. In recent years, the appropriate dose of enoxaparin for VTE prophylaxis in obese patients has been evaluated in 3 clinical studies. All studies enrolled patients with various risk factors for thromboembolism and evaluated different enoxaparin dosing regimens. End point analyses were all based on anti-Xa levels.

CONCLUSIONS

Due to a lack of well-designed prospective, randomized control studies, varying doses of enoxaparin are used for VTE prophylaxis in hospitalized, obese patients. All doses studied were monitored using anti-Xa levels. Patient follow-up was of short duration in all studies and did not show long-term effectiveness of enoxaparin. Prospective, randomized controlled studies are warranted to show efficacy and safety of one dosage regimen over another.

Smoking and alcohol use in gastric bypass patients

Bariatric surgery may increase the risk of substance use. The purpose of this study was to prospectively assess smoking and alcohol use before and after bariatric surgery, identify characteristics associated with alcohol use and smoking, and examine substance use and weight loss. Participants (N = 155, mean = 50.1 ± 11.3 y and 45.7 ± 7.0 kg/m(2)) were Roux-en-Y gastric bypass (RYGB) patients that completed surveys on substance use preoperatively and postoperatively. Alcohol use decreased significantly from the preoperative (72.3%) to the postoperative (63.2%) period. As preoperative alcohol quantity rose, the odds of consuming any alcohol postoperatively increased six-fold. Higher BMI increased the odds of high alcohol consumption. Older age decreased the odds of alcohol use and smoking. Smoking status did not differ pre- (19.4%) to post- (14.8%) surgery. Alcohol use and smoking were not associated with weight loss. After weight-loss surgery, alcohol use declined but smoking rates did not significantly change. Younger patients were more likely to use alcohol and smoke postoperatively. Patients with a higher BMI or a history of substance use may be more likely to use alcohol postoperatively.

Psychiatric aspects of bariatric surgery

While most conventional treatments for individuals with severe obesity have a modest and short lived impact bariatric surgery has been consistently shown to result in long-term marked weight loss and significant improvement in medical comorbidities. Empirical data suggest a high prevalence of mental disorders among bariatric surgery candidates. This article reviews specific areas of psychopathology, problems in using psychopharmacological medications post-surgery, body contouring, and recommendations for pre and post-surgery care. Available research indicates a decrease in psychiatric symptoms post-surgery. However, in some patients the improvement appears to erode over time. Therefore, bariatric surgery patients should be monitored not only before surgery but also following surgery and referred for mental health treatment if problems develop.