Variation and outcomes of liver-reducing dietary regimens before bariatric surgery: a national retrospective cohort study.

BACKGROUND: Liver-reducing diets (LRDs) are mandated prior to bariatric surgery, but there are no guidelines on their implementation. OBJECTIVE: To establish the variation and effectiveness of LRDs utilized in clinical practice. SETTING: A nationwide, multicenter, retrospective cohort study. METHODS: A total of 1699 adult patients across 14 bariatric centers in the United Kingdom were included. Multilevel logistic regression models were developed to examine factors predictive of 5% weight loss. RESULTS: Most centers (n = 9) prescribed an 800- to 1000-kcal diet, but the duration and formulation of diet was variable. Overall, 30.6% (n = 510) of patients achieved 5% weight loss during the LRD. After adjustment for preoperative weight, women had reduced odds (odds ratio [OR], .65; 95% confidence interval [CI], .48-.88; P = .005), while increasing age (OR, 1.01; 95% CI, 1.00-1.02; P = .043) and having type 2 diabetes (OR, 1.49; 95% CI, 1.16-1.92; P = .002) increased odds of 5% weight loss. A normal consistency food LRD (OR, .64; 95% CI, .42-.98; P = .041) and energy prescription of >1200 kcals/d (OR, .33; 95% CI, .13-.83; P = .019) reduced odds, while an LRD with a duration of 3 weeks (OR, 2.28; 95% CI, 1.02-5.09; P = .044) or greater increased odds of 5% weight loss. CONCLUSIONS: There is wide variation in how LRDs are delivered in clinical practice, highlighting the need for an evidence-based consensus. Our findings suggest the optimal LRD before bariatric surgery contains 800 to 1200 kcals/d over a duration of 3 to 4 weeks. Further research is required to determine the optimal formulation of LRD and whether women may require a lower-energy LRD than men.

Reduced phenytoin levels in an epileptic patient following Roux-En-Y gastric bypass for obesity.

Despite widespread uptake of bariatric procedures for severe obesity, changes in pharmacodynamics after surgery are poorly understood. We report an epileptic patient who had a seizure following gastric bypass, although he had been asymptomatic for 30 years and without any change in his treatment. Phenytoin levels were undetectable despite a high dose. Drugs with a narrow therapeutic range such as phenytoin should be prescribed with caution after bariatric surgery.

Remission of type 2 diabetes after gastric bypass and banding: mechanisms and 2 year outcomes.

OBJECTIVE: To investigate the rate of type 2 diabetes remission after gastric bypass and banding and establish the mechanism leading to remission of type 2 diabetes after bariatric surgery. SUMMARY BACKGROUND DATA: Glycemic control in type 2 diabetic patients is improved after bariatric surgery. METHODS: In study 1, 34 obese type 2 diabetic patients undergoing either gastric bypass or gastric banding were followed up for 36 months. Remission of diabetes was defined as patients not requiring hypoglycemic medication, fasting glucose below 7 mmol/L, 2 hour glucose after oral glucose tolerance test below 11.1 mmol/L, and glycated haemoglobin (HbA1c) <6%. In study 2, 41 obese type 2 diabetic patients undergoing either bypass, banding, or very low calorie diet were followed up for 42 days. Insulin resistance (HOMA-IR), insulin production, and glucagon-like peptide 1 (GLP-1) responses after a standard meal were measured. RESULTS: In study 1, HbA1c as a marker of glycemic control improved by 2.9% after gastric bypass and 1.9% after gastric banding at latest follow-up (P < 0.001 for both groups). Despite similar weight loss, 72% (16/22) of bypass and 17% (2/12) of banding patients (P = 0.001) fulfilled the definition of remission at latest follow-up. In study 2, within days, only bypass patients had improved insulin resistance, insulin production, and GLP-1 responses (all P < 0.05). CONCLUSIONS: With gastric bypass, type 2 diabetes can be improved and even rapidly put into a state of remission irrespective of weight loss. Improved insulin resistance within the first week after surgery remains unexplained, but increased insulin production in the first week after surgery may be explained by the enhanced postprandial GLP-1 responses.

Ghrelin and metabolic surgery.

Metabolic surgery is the most effective treatment for morbid obesity. Ghrelin has been implicated to play a role in the success of these procedures. Furthermore, these operations have been used to study the gut-brain axis. This article explores this interaction, reviewing the available data on changes in ghrelin levels after different surgical procedures.

The gut hormone response following Roux-en-Y gastric bypass: cross-sectional and prospective study.

BACKGROUND: Bariatric surgery is the most effective treatment option for obesity, and gut hormones are implicated in the reduction of appetite and weight after Roux-en-Y gastric bypass. Although there is increasing interest in the gut hormone changes after gastric bypass, the long-term changes have not been fully elucidated. METHODS: Thirty-four participants were studied cross-sectionally at four different time points, pre-operatively (n = 17) and 12 (n = 6), 18 (n = 5) and 24 months (n = 6) after laparoscopic Roux-en-Y gastric bypass. Another group of patients (n = 6) were studied prospectively (18-24 months). All participants were given a standard 400 kcal meal after a 12-h fast, and plasma levels of peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) were correlated with changes in appetite over 3 h using visual analogue scores. RESULTS: The post-operative groups at 12, 18 and 24 months had a higher post-prandial PYY response compared to pre-operative (p < 0.05). This finding was confirmed in the prospective study at 18 and 24 months. There was a trend for increasing GLP-1 response at 18 and 24 months, but this did not reach statistical significance (p = 0.189) in the prospective study. Satiety was significantly reduced in the post-operative groups at 12, 18 and 24 months compared to pre-operative levels (p < 0.05). CONCLUSIONS: Roux-en-Y gastric bypass causes an enhanced gut hormone response and increased satiety following a meal. This response is sustained over a 24-month period and may partly explain why weight loss is maintained.

Three hundred laparoscopic Roux-en-Y gastric bypasses: managing the learning curve in higher risk patients.

BACKGROUND: Bariatric surgery is expanding and the increasing workload needs to be undertaken safely in new surgical centres with no previous bariatric experience. The laparoscopic Roux-en-Y gastric bypass (LRYGB) has a steep learning curve with documented high risk. We present the results for the first 300 cases of LRYGB in a new centre. METHODS: Three hundred consecutive patients underwent LRYGB performed by a single surgeon. Four external surgeons mentored eight cases in the first 50. Demographic characteristics, body mass index (BMI) and operative time were collected prospectively and the Obesity Surgery Mortality Risk Score was used for risk stratification. RESULTS: The mean BMI of the patients increased during the series from 49.0 for the first group to 50.2 for the second group and to 51.0 for the third group (p < 0.05). The number of high-risk patients measured with the OS-MRS was 19/300 (6.3%) in the whole series. The mean operative time decreased from 163 min for the first 100 patients to 119 min for the second 100 and 94 for the third (p < 0.0001). In the first group, there were nine reoperations and two conversions to open surgery, compared to two reoperations and one conversion in the second group (p < 0.05). In the whole series, there were 12 early complications requiring re-operation, four conversions to open surgery and one mortality (patient 110, heart failure within 24 h). CONCLUSIONS: A mentoring process ensures that LRYGB can be done safely in a newly established bariatric centre. The operative time reduces markedly after the learning curve.

Obesity, gut hormones, and bariatric surgery.

Obesity is becoming the healthcare epidemic of this century. Bariatric surgery is the only effective treatment for morbid obesity. Gut hormones are key players in the metabolic mechanisms causing obesity. In this review we explore the role of these hormones as facilitators of appetite control and weight loss after bariatric surgery, and we describe the now established gut-brain axis.

After bariatric surgery, what vitamins should be measured and what supplements should be given?

Bariatric surgery is the most effective treatment for morbid obesity. Although calorie malabsorption does not occur in most bariatric procedures, micronutrient deficiencies are possible. Multivitamin supplementation is essential following bariatric surgery. The recommendation would be to screen for multivitamin deficiencies prior to surgery and to monitor vitamin levels postoperatively at regular intervals. In this paper, we review the data for screening and supplementation after bariatric procedures for different vitamins.