Edward H. Livingston

Meta-analysis: surgical treatment of obesity.

Context The effectiveness of surgical therapy in the treatment of obesity is unclear. Contribution Many published studies of obesity surgery have significant limitations, and case series make up much of the evidence. Evidence is complicated by the heterogeneity of procedures studied. However, surgery can result in substantial amounts of weight loss (20 to 30 kg) for markedly obese individuals. One cohort study documented weight loss for 8 years with associated improvements in comorbid conditions, such as diabetes. Complications of surgery appear to occur in about 20% of patients. Implications Those considering surgical treatment for obesity should understand that, although patients who have surgery can lose substantial amounts of weight, the evidence base for these treatments is limited. The Editors The prevalence of obesity in the United States is reaching epidemic proportions. An estimated 30% of individuals met the criteria for obesity in 19992002 (1, 2), and many industrialized countries have seen similar increases. The health consequences of obesity include heart disease, diabetes, hypertension, hyperlipidemia, osteoarthritis, and sleep apnea (3-7). Weight loss of 5% to 10% has been associated with marked reductions in the risk for these chronic diseases and with reducing the incidence of diabetes (8-14). The increasing numbers of obese individuals have led to intensified interest in surgical treatments to achieve weight loss, and a variety of surgical procedures have been used (Figure 1). Bariatric surgery was first performed in 1954 with the introduction of the jejunoileal bypass, which bypasses a large segment of small intestine by connecting proximal small intestine to distal small intestine. With this procedure, weight loss occurs secondary to malabsorption from reduction of upstream pancreatic and biliary contents. However, diarrhea and nutritional deficiencies were common, and this procedure was discontinued because of the complication of irreversible hepatic cirrhosis. With the development of surgical staplers came the introduction of gastroplasty procedures by Gomez in 1981 (15) and Mason in 1982 (16). In these early procedures, the upper portion of the stomach was stapled into a small gastric pouch with an outlet (that is, a stoma) to the remaining distal stomach, which limited the size of the meal and induced early satiety. These procedures were prone to staple-line breakdown or stoma enlargement and were modified in turn by the placement of a band around the stoma (vertical banded gastroplasty). Figure 1. Surgical procedures. The first gastric bypass was reported in 1967 by Mason and Ito (17). It combined the creation of a small gastric pouch with bypassing a portion of the upper small intestine. Additional modifications resulted in the Roux-en-Y gastric bypass (RYGB), a now common operation that involves stapling the upper stomach into a 30-mL pouch and creating an outlet to the downstream small intestine. The new food limb joins with the biliopancreatic intestine after a short distance. This procedure, performed laparoscopically or by using an open approach, generates weight loss by limiting gastric capacity, causing mild malabsorption, and inducing hormonal changes. A second common technique, particularly outside of the United States, is the laparoscopic adjustable gastric band. This device is positioned around the uppermost portion of the stomach and can be adjusted to allow tailoring of the stoma outlet, which controls the rate of emptying of the pouch and meal capacity. Another procedure, preferred by a number of surgeons, is the biliopancreatic bypass, which combines a limited gastrectomy with a long Roux limb intestinal bypass that creates a small common channel (that is, an intestine where food and biliopancreatic contents mix). This procedure can be combined with a duodenal switch, which maintains continuity of the proximal duodenum with the stomach and uses a long limb Roux-en-Y bypass to create a short common distal channel. These latter 2 procedures generate weight loss primarily through malabsorption. Recent worldwide survey data from 2002 and 2003 show that gastric bypass is the most commonly performed weight loss procedure (65.1%) (18). Slightly more than half of gastric bypasses are done laparoscopically. Overall, 24% of cases are laparoscopic adjustable band procedures; 5.4% are vertical banded gastroplasties; and 4.9% are biliopancreatic diversion, with or without the duodenal switch. In California, the number of bariatric cases increased 6-fold between 1996 and 2000 (19), from 1131 cases to 6304; an estimated 140000 procedures were performed in the United States in 2004. With this escalation in the number of procedures, there have been reports of high postoperative complication rates (20-24). Because of these reports and the increasing use of obesity surgery, we were asked to review the literature to estimate the effectiveness of bariatric surgery relative to nonsurgical therapy for weight loss and reduction in preoperative obesity-related comorbid conditions. We were also asked to compare outcomes of surgical techniques. This paper is part of a larger evidence report titled Pharmacological and Surgical Treatment of Obesity, which was prepared for the Agency for Healthcare Research and Quality and is available at www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=hstat1a.chapter.19289. Methods Literature Search and Selection We began with an electronic search of MEDLINE on 16 October 2002, followed by a search of EMBASE and subsequent periodic search updates (on 22 May, 2 June, 12 June, and 3 July 2003). We also assessed existing reviews of surgical therapy for obesity (10, 25, 26). Three reviewers independently reviewed the studies, abstracted data, and resolved disagreements by consensus (2 reviewers per study). The principal investigator settled any unresolved disagreements. We focused on studies that assessed surgery and used a concurrent comparison group. This category includes randomized, controlled trials (RCTs); controlled clinical trials; and cohort studies. A brief scan of the literature showed that these types of studies were rare. Therefore, we also elected to include case series with 10 or more patients, since these studies can be used to assess adverse events and could potentially augment the efficacy data from comparative studies. Publication bias is one potential limitation of analyzing the available literature because poor or negative results are not as likely to be reported as are successes or positive results. Extraction of Study-Level Variables We abstracted data from the articles, including number of patients and comorbid conditions, adverse events, types of outcome measures, and time from intervention until outcome. Detailed data were also collected on characteristics of the study samples, including median age, percentage of women, median baseline weight (in kilograms or body mass index [BMI]), percentage of patients with comorbid conditions at baseline (diabetes, hypertension, dyslipidemia, and sleep apnea), percentage of improvement or resolution of preexisting comorbid conditions, and median follow-up time. We also recorded whether the case series studies reported on consecutive patients. Choice of Outcomes The main outcomes of interest were weight loss, mortality, complication rates, and control of obesity-related comorbid conditions. We used the most commonly reported measurement of weight loss, that is, kilograms, which allowed us to include the greatest number of studies. Among 111 surgical studies reporting weight loss, 43 reported weight loss in kilograms or pounds, 17 reported excess weight loss or some variant, 46 reported both of these outcomes, and 5 reported neither. A total of 89 studies had sufficient data to be included in the weight loss analysis. Because weight loss achieves health benefits primarily by reducing the incidence or severity of weight-related comorbid conditions, we also compared the effects on these outcomes. Quality of life, an important outcome in assessing tradeoffs between benefits and risks, was reported infrequently. Statistical Analyses Because we included both comparative studies and case series, we conducted several types of analyses. The vast number of types of surgical procedures and technical variations required that we aggregate those that were clinically similar and identify the comparisons that were of most interest to the clinical audience. On the basis of discussions with bariatric surgeons, we categorized obesity surgery procedures by procedure type (for example, gastric bypass, vertical banded gastroplasty), laparoscopic or open approach, and specific surgical details such as length of Roux limb (see the larger evidence report for details). Analysis of the Efficacy of Surgical Weight Loss We extracted the mean weight loss and standard deviation at 12 postoperative months and at the maximum follow-up time (36 months). These times were chosen because they are clinically relevant and are most commonly reported. Of the 89 weight loss studies, 71 reported baseline BMI (average, 47.1 kg/m2), 16 reported baseline weight in kilograms or pounds (average, 123.3 kg), and 2 did not report either. The average age of patients was 38 years, and more than three quarters were women. For comparative studies that reported a within-study comparison of 2 procedures, a mean difference was calculated. Mean differences were pooled by using a random-effects model, and 95% CIs were estimated; the same method was used to determine a pooled mean weight loss for each group considering all studies combined. However, mean difference in weight loss was not calculated. Analysis of Surgery Mortality We recorded the number of deaths observed and the total number of patients in each procedure group. If the study self-identified the deaths as early or postoperative or as occurring within 30 days of the surgery, we termed these early deaths. If the

Male Gender is a Predictor of Morbidity and Age a Predictor of Mortality for Patients Undergoing Gastric Bypass Surgery

PurposeTo determine preoperative risk factors predictive of adverse outcomes after gastric bypass surgery. Summary Background DataGastric bypass results in sustained weight loss for seriously obese patients, but perioperative complications can be formidable. Preoperative risk assessment is important to establish the risk-benefit ratio for patients undergoing these operations. MethodsData for 10 risk factors predictive of adverse outcomes were collected on 1,067 consecutive patients undergoing gastric bypass surgery at the UCLA Medical Center from December 1993 until June 2000. Univariate analyses were performed for individual risk factors to determine their potential significance as predictors for complications. All 10 risk factors were entered into a logistic regression model to determine their significance as predictors for complications. Sensitivity analysis was performed. ResultsUnivariate analysis revealed that male gender and weight were predictive of severe life-threatening adverse outcomes. Multistep logistic regression yielded only male gender as a risk factor. Male patients were heavier than female patients on entry to the study, accounting for weight as a potential risk factor. Patients older than 55 years had a threefold higher mortality from surgery than younger patients, although the complication rate, 5.8%, was the same in both groups. Sensitivity analysis demonstrated that the risk for severe life-threatening adverse outcomes in women increased from 4% for a 200-lb female patient to 7.5% for a 600-lb patient. The risk increased from 7% for a 200-lb male patient to 13% for a 600-lb patient. ConclusionsLarge male patients are at greater risk for severe life-threatening complications than smaller and/or female patients. Risk factors thought to be predictive of adverse outcomes, such as a history of smoking or diabetes, proved not to be significant in this analysis. Older patients had the same complication rate but a threefold higher mortality, suggesting that they lack the reserve to recover from complications when they occur.

Pregnancy and fertility following bariatric surgery: a systematic review.

CONTEXT Use of bariatric surgery has increased dramatically during the past 10 years, particularly among women of reproductive age. OBJECTIVES To estimate bariatric surgery rates among women aged 18 to 45 years and to assess the published literature on pregnancy outcomes and fertility after surgery. EVIDENCE ACQUISITION Search of the Nationwide Inpatient Sample (1998-2005) and multiple electronic databases (Medline, EMBASE, Controlled Clinical Trials Register Database, and the Cochrane Database of Reviews of Effectiveness) to identify articles published between 1985 and February 2008 on bariatric surgery among women of reproductive age. Search terms included bariatric procedures, fertility, contraception, pregnancy, and nutritional deficiencies. Information was abstracted about study design, fertility, and nutritional, neonatal, and pregnancy outcomes after surgery. EVIDENCE SYNTHESIS Of 260 screened articles, 75 were included. Women aged 18 to 45 years accounted for 49% of all patients undergoing bariatric surgery (>50,000 cases annually for the 3 most recent years). Three matched cohort studies showed lower maternal complication rates after bariatric surgery than in obese women without bariatric surgery, or rates approaching those of nonobese controls. In 1 matched cohort study that compared maternal complication rates in women after laparoscopic adjustable gastric band surgery with obese women without surgery, rates of gestational diabetes (0% vs 22.1%, P < .05) and preeclampsia (0% vs 3.1%, P < .05) were lower in the bariatric surgery group. Findings were supported by 13 other bariatric cohort studies. Neonatal outcomes were similar or better after surgery compared with obese women without laparoscopic adjustable gastric band surgery (7.7% vs 7.1% for premature delivery; 7.7% vs 10.6% for low birth weight, P < .05; 7.7% vs 14.6% for macrosomia, P < .05). No differences in neonatal outcomes were found after gastric bypass compared with nonobese controls (26.3%-26.9% vs 22.4%-20.2% for premature delivery, P = not reported [1 study] and P = .43 [1 study]; 7.7% vs 9.0% for low birth weight, P = not reported [1 study]; and 0% vs 2.6%-4.3% for macrosomia, P = not reported [1 study] and P = .28 [1 study]). Findings were supported by 10 other studies. Studies regarding nutrition, fertility, cesarean delivery, and contraception were limited. CONCLUSION Rates of many adverse maternal and neonatal outcomes may be lower in women who become pregnant after having had bariatric surgery compared with rates in pregnant women who are obese; however, further data are needed from rigorously designed studies.

Endocrine and Nutritional Management of the Post-Bariatric Surgery Patient: An Endocrine Society Clinical Practice Guideline

OBJECTIVE We sought to provide guidelines for the nutritional and endocrine management of adults after bariatric surgery, including those with diabetes mellitus. The focus is on the immediate postoperative period and long-term management to prevent complications, weight regain, and progression of obesity-associated comorbidities. The treatment of specific disorders is only summarized. PARTICIPANTS The Task Force was composed of a chair, five additional experts, a methodologist, and a medical writer. It received no corporate funding or remuneration. CONCLUSIONS Bariatric surgery is not a guarantee of successful weight loss and maintenance. Increasingly, patients regain weight, especially those undergoing restrictive surgeries such as laparoscopic banding rather than malabsorptive surgeries such as Roux-en-Y bypass. Active nutritional patient education and clinical management to prevent and detect nutritional deficiencies are recommended for all patients undergoing bariatric surgery. Management of potential nutritional deficiencies is particularly important for patients undergoing malabsorptive procedures, and strategies should be employed to compensate for food intolerance in patients who have had a malabsorptive procedure to reduce the risk for clinically important nutritional deficiencies. To enhance the transition to life after bariatric surgery and to prevent weight regain and nutritional complications, all patients should receive care from a multidisciplinary team including an experienced primary care physician, endocrinologist, or gastroenterologist and consider enrolling postoperatively in a comprehensive program for nutrition and lifestyle management. Future research should address the effectiveness of intensive postoperative nutritional and endocrine care in reducing morbidity and mortality from obesity-associated chronic diseases.

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice for the Perioperative Nutritional, Metabolic, and Nonsurgical Support of the Bariatric Surgery Patient

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice are systematically developed statements to assist healthcare professionals in medical decision making for specific clinical conditions. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment was applied. These guidelines are a working document that reflects the state of the field at the time of publication. Because rapid changes in this area are expected, periodic revisions are inevitable. We encourage medical professionals to use this information in conjunction with their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances. The American Society for Parenteral & Enteral Nutrition fully endorses sections of these guidelines that address the metabolic and nutritional management of the bariatric surgical patient.

Long-term follow-up after bariatric surgery: a systematic review

IMPORTANCE Bariatric surgery is an accepted treatment for obesity. Despite extensive literature, few studies report long-term follow-up in cohorts with adequate retention rates. OBJECTIVE To assess the quality of evidence and treatment effectiveness 2 years after bariatric procedures for weight loss, type 2 diabetes, hypertension, and hyperlipidemia in severely obese adults. EVIDENCE REVIEW MEDLINE and Cochrane databases were searched from 1946 through May 15, 2014. Search terms included bariatric surgery, individual bariatric procedures, and obesity. Studies were included if they described outcomes for gastric bypass, gastric band, or sleeve gastrectomy performed on patients with a body mass index of 35 or greater, had more than 2 years of outcome information, and had follow-up measures for at least 80% of the initial cohort. Two investigators reviewed each study and a third resolved study inclusion disagreements. FINDINGS Of 7371 clinical studies reviewed, 29 studies (0.4%, 7971 patients) met inclusion criteria. All gastric bypass studies (6 prospective cohorts, 5 retrospective cohorts) and sleeve gastrectomy studies (2 retrospective cohorts) had 95% confidence intervals for the reported mean, median, or both exceeding 50% excess weight loss. This amount of excess weight loss occurred in 31% of gastric band studies (9 prospective cohorts, 5 retrospective cohorts). The mean sample-size-weighted percentage of excess weight loss for gastric bypass was 65.7% (n = 3544) vs 45.0% (n = 4109) for gastric band. Nine studies measured comorbidity improvement. For type 2 diabetes (glycated hemoglobin <6.5% without medication), sample-size-weighted remission rates were 66.7% for gastric bypass (n = 428) and 28.6% for gastric band (n = 96). For hypertension (blood pressure <140/90 mm Hg without medication), remission rates were 38.2% for gastric bypass ( n = 808) and 17.4% for gastric band (n = 247). For hyperlipidemia (cholesterol <200 mg/dL, high-density lipoprotein >40 mg/dL, low-density lipoprotein <160 mg/dL, and triglycerides <200 mg/dL), remission rates were 60.4% for gastric bypass (n = 477) and 22.7% for gastric band (n = 97). CONCLUSIONS AND RELEVANCE Very few bariatric surgery studies report long-term results with sufficient patient follow-up to minimize biased results. Gastric bypass has better outcomes than gastric band procedures for long-term weight loss, type 2 diabetes control and remission, hypertension, and hyperlipidemia. Insufficient evidence exists regarding long-term outcomes for gastric sleeve resections.

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery medical guidelines for clinical practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient.

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice are systematically developed statements to assist health‐care professionals in medical decision making for specific clinical conditions. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment was applied.

Disconnect Between Incidence of Nonperforated and Perforated Appendicitis: Implications for Pathophysiology and Management

Objective:Appendicitis has been declining in frequency for several decades. During the past 10 years, its preoperative diagnosis has been made more reliable by improved computed tomography (CT) imaging. Thresholds for surgical exploration have been lowered by the increased availability of laparoscopic exploration. These innovations should influence the number of appendectomies performed in the United States. We analyzed nationwide hospital discharge data to study the secular trends in appendicitis and appendectomy rates. Methods:All appendicitis and appendiceal operations reported to the National Hospital Discharge Survey (NHDS) 1970–2004 were classified as perforated, nonperforated, negative, and incidental appendectomies and analyzed over time and by various demographic measures. Secular trends in the population-based incidence rates of nonperforated and perforated appendicitis and negative and incidental appendectomy were examined. Results:Nonperforated appendicitis rates decreased between 1970 and 1995 but increased thereafter. The 25-year decreasing trend was accounted for almost entirely by a decreasing incidence in the 10–19 year age group. The rise after 1995 occurred in all age groups above 5 years and paralleled increasing rates of CT imaging and laparoscopic surgery on the appendix. Since 1995 the negative appendectomy rate has been falling, especially in women, and incidental appendectomies, frequent in prior decades, have been rarely performed. Despite these large changes, the rate of perforated appendicitis has increased steadily over the same period. Although perforated and nonperforated appendicitis rates were correlated in men, they were not significantly correlated in women nor were there significant negative correlations between perforated and negative appendectomy rates. Conclusion:The 25-year decline in nonperforated appendicitis and the recent increase in appendectomies coincident with more frequent use of CT imaging and laparoscopic appendectomies did not result in expected decreases in perforation rates. Similarly, time series analysis did not find a significant negative relationship between negative appendectomy and perforation rates. This disconnection of trends suggests that perforated and nonperforated appendicitis may have different pathophysiologies and that nonoperative management with antibiotic therapy may be appropriate for some initially nonperforated cases. Further efforts should be directed at identifying preoperative characteristics associated with nonperforating appendicitis that may eventually allow surgeons to defer operation for those cases of nonperforating appendicitis that have a low perforation risk.

Sensory neurons signal for an increase in rat gastric mucosal blood flow in the face of pending acid injury

Disruption of the gastric mucosal barrier is quickly followed by an increase in gastric mucosal blood flow, which is thought to be a defensive reaction to prevent further injury. This study examined how this increase in blood flow is brought about. When the stomach of urethane-anesthetized rats was perfused with 0.15N HCl, disruption of the gastric mucosal barrier with 15% ethanol increased the disappearance of acid from the gastric lumen and enhanced gastric mucosal blood flow. This increase in blood flow was blocked by local arterial infusion of tetrodotoxin (60 ng/min) to the stomach and by chemical ablation of capsaicin-sensitive sensory neurons. Inhibition of the blood flow increase was associated with exaggeration of gross and histological injury to the mucosa. IV injection of atropine (0.2 mg/kg) or pyrilamine (2 mg/kg) did not affect blood flow increase in response to barrier disruption, whereas morphine injection (2 mg/kg) inhibited it. The current findings show that the increase in gastric mucosal blood flow that follows disruption of the gastric mucosal barrier in the presence of acid is mediated by sensory neurons that seem to monitor acid back-diffusion and in turn signal for a protective increase in blood flow.

Afferent nerve-mediated protection against deep mucosal damage in the rat stomach☆

Intragastric capsaicin protects against ethanol-induced gross mucosal lesion formation by stimulation of afferent nerve endings in the rat stomach. The aims of the present study were to examine histologically the protective effect of capsaicin and to test whether this effect is related to changes in mucosal eicosanoid formation and mucosal blood flow. Intragastric capsaicin (160 microM) significantly reduced gross mucosal lesion formation induced by 25% ethanol. Light microscopy revealed that the depth of erosions was attenuated likewise. However, capsaicin did not prevent ethanol from causing superficial damage to the mucosa as observed by light and scanning electron microscopy. The protective action of capsaicin against ethanol remained unchanged by a dose of indomethacin that reduced the ex vivo formation of prostaglandin E2 and 6-oxo-prostaglandin F1 alpha in the gastric mucosa by about 90%. Capsaicin alone did not affect the ex vivo formation of these prostaglandins and of leukotriene C4. Intragastric capsaicin (160 microM) enhanced gastric mucosal blood flow by 89% as measured by the hydrogen gas clearance technique. This effect was also observed when capsaicin was administered together with 25% ethanol. These data indicate that afferent nerve stimulation by intragastric capsaicin protects against deep mucosal damage in response to ethanol, an effect that seems related to an increase in mucosal blood flow but not to eicosanoid formation.