Gastric bypass surgery in the United States, 1998-2002

Cross-Regional View of Functional and Taxonomic Microbiota Composition in Obesity and Post-obesity Treatment Shows Country Specific Microbial Contribution

Gut microbiota has been shown to have an important influence on host health. The microbial composition of the human gut microbiota is modulated by diet and other lifestyle habits and it has been reported that microbial diversity is altered in obese people. Obesity is a worldwide health problem that negatively impacts the quality of life. Currently, the widespread treatment for obesity is bariatric surgery. Interestingly, gut microbiota has been shown to be a relevant factor in effective weight loss after bariatric surgery. Since that the human gut microbiota of normal subjects differs between geographic regions, it is possible that rearrangements of the gut microbiota in dysbiosis context are also region-specific. To better understand how gut microbiota contribute to obesity, this study compared the composition of the human gut microbiota of obese and lean people from six different regions and showed that the microbiota compositions in the context of obesity were specific to each studied geographic location. Furthermore, we analyzed the functional patterns using shotgun DNA metagenomic sequencing and compared the results with other obesity-related metagenomic studies, we observed that microbial contribution to functional pathways were country-specific. Nevertheless, our study showed that although microbial composition of obese patients was country-specific, the overall metabolic functions appeared to be the same between countries, indicating that different microbiota components contribute to similar metabolic outcomes to yield functional redundancy. Furthermore, we studied the microbiota functional changes of obese patients after bariatric surgery, by shotgun metagenomics sequencing and observed that changes in functional pathways were specific to the type of obesity treatment. In all, our study provides new insights into the differences and similarities of obese gut microbiota in relation to geographic location and obesity treatments.

Long-Term (over 10 Years) Retrospective Follow-up of Laparoscopic Adjustable Gastric Banding

BACKGROUND

Laparoscopic adjustable gastric banding (LAGB) placements have progressively decreased in recent years. This is related to poor long-term weight loss outcomes and necessity for revision or removal of these bands. Long-term outcome results following LAGB are limited. The aim of our study was to determine the long-term outcome after LAGB at our institution.

OBJECTIVES

The aim of our study was to determine the long-term outcome after LAGB at our institution.

SETTING

The setting of this is Academic Center, Israel.

METHODS

Patients who underwent LAGB between 1999 and 2004 were reviewed. Patient comorbidities and weight loss parameters were collected preoperatively and at defined postoperative periods. Improvement in weight loss was defined as percent excess weight lost, and improvement in comorbidities was defined based on standardized reporting definitions.

RESULTS

In total, 74 (80%) patients who underwent LAGB met inclusion criteria. The mean age at LAGB placement was 50.5 ± 9.6 years, and the mean body mass index (BMI) was 45.5 ± 4.8 kg/m². Preoperative comorbidities were diabetes mellitus (13.5%), hypertension (32%), hyperlipidemia (12.1%), obstructive sleep apnea (5.4%), joints disease (10.8%), mood disorders (5.4%), and gastro-esophageal reflux disease (GERD) symptoms (8.1%). The mean follow-up was 162.96 ± 13.9 months; 44 patients (59.4%) had their band removed, and 22 (30%) had another bariatric surgery. The follow-up BMI was 35.7 ± 6.9 (p < 0.001), and the % total weight loss was 21.0 ± 0.13. There was no improvement in any of the comorbidities. GERD symptoms worsened at long-term follow-up (p < 0.001). Undergoing another bariatric procedure was associated with a higher weight loss (OR 12.8; CI 95% 1.62-23.9; p = 0.02).

CONCLUSION

LAGB required removal in the majority of our patients and showed poor resolution of comorbidities with worsening of GERD-related symptoms. Patients who go on to have another bariatric procedure have more durable weight loss outcomes.

Life Expectancy Benefits of Gastric Bypass Surgery

Bariatric surgery is the most effective treatment for achieving sustained weight loss in morbidly obese patients. Although the use of gastric bypass is growing rapidly, the potential life expectancy benefits of the procedure are unknown. We created a Markov decision analysis model to examine the effect of gastric bypass surgery on life expectancy in morbidly obese patients (body mass index [BMI] = 40 kg/m2). Input assumptions for the model were obtained from published life tables (baseline mortality risks), epidemiologic studies (obesity-related excess mortality), and large case series (surgical outcomes). In our baseline analysis, a 40-year-old woman (BMI = 40 kg/m2) would gain 2.6 years of life expectancy by undergoing gastric bypass (38.7 years versus 36.2 years without surgery). In sensitivity analysis, life-years gained with surgery remained substantial when assumptions were varied across reasonable ranges for surgical mortality risk (1.0-3.0 years) and effectiveness (0.9-4.4 years). Life-years gained with gastric bypass surgery did not vary considerably by age and sex subgroups. Relative to other major surgical procedures, gastric bypass for morbid obesity is associated with substantial gains in life expectancy. Long- term data from prospective studies are needed to confirm this finding.

Surgery for type 2 diabetes: the case for Roux-en-Y gastric bypass

The Roux-en-Y gastric bypass (RYGB) has traditionally been the most common bariatric procedure. Long-term data on the efficacy of RYGB demonstrate a long-lasting benefit in weight loss and control of the metabolic syndrome. Although observations of type 2 diabetes (T2D) resolution after RYGB have been reported for 3 decades, it was not until recently that multiple randomized trials comparing RYGB to medical therapy verified the same thing: RYGB leads to significantly greater diabetes control and remission. Even though T2D can relapse, there remains a significant overall benefit of bariatric surgery regarding the downstream effects of T2D: cardiovascular risk and micro- and macrovascular complications. Limited data are available on the comparative effectiveness of RYGB and sleeve gastrectomy in improving glucose homeostasis, but studies including both surgical procedures suggest that the benefit of RYGB in T2D may be more profound. Although further research is needed to examine closely any differences between these 2 procedures, multiple studies underscore the unprecedented value of bariatric surgery for the control and remission of T2D.

Improved rodent maternal metabolism but reduced intrauterine growth after vertical sleeve gastrectomy

Obesity has profound negative consequences on female reproduction as well as on the metabolic health of offspring. Bariatric surgery is the most effective method for sustained weight loss. A critical question is whether bariatric surgery can reverse the deleterious effects of obesity on both female reproduction and subsequent offspring. Vertical sleeve gastrectomy (VSG) is a bariatric procedure rapidly growing in popularity because it provides weight loss and other metabolic benefits that are comparable to those offered by the more complicated Roux-en-Y gastric bypass (RYGB). Female rats rendered obese on a high-fat diet (HFD) underwent either VSG or sham surgery. Like their male counterparts, females had significant metabolic improvements including reduced adiposity and improved glucose tolerance. After VSG, female rats showed a more normal reproductive cycle. Despite these maternal benefits, the offspring of dams receiving VSG were born smaller and lighter than offspring of control dams that underwent sham surgery. When maintained on an HFD after puberty, these adult offspring had a greater propensity to develop glucose intolerance and increased adiposity than the offspring of lean mothers or obese mothers who underwent sham surgery. These data suggest that weight loss alone by obese mothers is not sufficient to reverse the deleterious effects of an HFD and obesity on their offspring.

Bariatric surgery and bone disease: from clinical perspective to molecular insights

The use of bariatric surgery for the treatment of morbid obesity has increased annually for the last decade. Although many studies have demonstrated the efficacy and durability of bariatric surgery for weight loss, there are limited data regarding long-term side effects of these procedures. Recently, there has been an increased focus on the impact of bariatric surgery on bone metabolism. Bariatric surgery utilizes one or more of three mechanisms of action resulting in sustained weight loss. These include restriction (gastric banding, vertical banded gastroplasty and sleeve gastrectomy), malabsorption surgery with or without associated restriction (Roux en Y gastric bypass, duodenal switch, biliopancreatic diversion and jejunoileal bypass) and changes in gut-derived hormones that control energy metabolism also referred to as neuro-hormonal control of energy metabolism (Roux en Y gastric bypass, duodenal switch, biliopancreatic diversion, jejunoileal bypass, surgical procedures as above and gastric sleeve). Weight reduction has been associated with increased bone resorption but the mechanisms behind this have not yet been fully elucidated. Each of the mechanisms of action of bariatric surgery (restriction, malabsorption, neuro-hormonal control of energy metabolism) may uniquely affect bone resorption. In this paper we will review the current state of knowledge regarding the relationship between bariatric surgery and bone metabolism with emphasis on possible mechanisms of action such as malnutrition, hormonal interactions and mechanical unloading of the skeleton. Further, we suggest a future research agenda.

Gastric bypass surgeries in New Hampshire, 1996-2007

Introduction

Obesity is a national epidemic. Gastric bypass surgery may be the only option that provides significant long-term weight loss for people who are morbidly obese (body mass index [BMI] ≥40 kg/m²) or for people who have a BMI of 35 or higher and have an obesity-related comorbidity. The objective of this study was to assess trends in gastric bypass surgery in New Hampshire.

Methods

Data from 1996 to 2007 from the New Hampshire Inpatient Hospital Discharge data set were analyzed. Records for patients with a gastric bypass surgery code were identified, and data on patients and hospitalizations were collected. A joinpoint regression model was used to analyze trends in surgery rates. Differences between patients and payer types were analyzed by using the Cochran–Mantel–Haenszel χ² test.

Results

The annual rate of gastric bypass surgery increased significantly from 3.3 to 22.4 per 100,000 adults between 1996 and 2007. The in-hospital death rate decreased significantly from 11% in 1996 to 1% in 2007. A greater proportion of women (78.1% during the study period) than men had this surgery. The average charge of a surgery decreased significantly from $44,484 in 1996 to $43,907 in 2007; by 2007, total annual charges were $13.9 million. Since 1996, private or "other" payers have been charged for nearly 80% of the total discharges.

Conclusion

The number of gastric bypass surgeries has increased in New Hampshire, and so have their cost. These increases may reflect a shortage in effective primary care and preventive measures to address the obesity epidemic.

The emergence of eating pathology after bariatric surgery: a rare outcome with important clinical implications

OBJECTIVE

The present review examines the extant literature regarding the post-operative development of eating disorders (e.g., EDNOS) in bariatric surgery patients.

METHOD

Internet, PsycINFO, Pubmed, and reference lists were examined to aggregate and compare literature from January 1985 to May 2010.

RESULTS

Several case studies and case series have investigated the emergence of eating disorders after bariatric surgery. Clinical considerations are outlined.

DISCUSSION

The development of classical eating disorders after bariatric surgery appears to be a rare occurrence; however, eating problems are far more common. Unfortunately no typology exists to classify such eating problems. Future research should examine the incidence, risk factors, symptomatology, course, and outcome of such eating disorders and eating problems. It is highly likely that such problems are underreported.

Future directions in bariatric surgery

Bariatric surgery is a field in rapid evolution, and the speed of this evolution has been accelerating over the last several decades. A thorough understanding of past developments is crucial to anticipating the future intelligently. The trends that have driven evolution historically often persist, and continue to be influential in the future. With this in mind, this article briefly outlines the historical and current trends in bariatric surgery, and follows the trajectory of these trends into the future to anticipate the technologies and techniques that will be most important to the field in the coming years.

What are obese patients able to eat after Roux-en-Y gastric bypass?

BACKGROUND/AIMS

The goal of this study was to analyze the likelihood of patients undergoing Roux-en-Y gastric bypass (RYGB) to recover a normal daily food intake, and the possible influence of dietary and exercise habits on long-term weight loss.

METHODS

The sample included 107 morbidly obese postoperative patients with at least 1 year of follow-up. The data collected included anthropometry, dietary and exercise habits, and information on ingested food. The unpaired Student's t test and the multivariate step-by-step regression were used in the analysis.

RESULTS

The mean preoperative BMI was 50.7 ± 11.8 kg/m(2), which had decreased at the moment of survey to 31.7 ± 5.4 kg/m(2). The mean % Excess of BMI Lost (%EBMIL) was 77.4 ± 23.7%. The nutritional components of diet were similar to those for the nonobese population. There were no significant differences in %EBMIL regarding number of meals, social habits, components of diet, or amount of exercise. The daily mean caloric intake (1,364 ± 293 kcal) was the only parameter significantly related to the %EBMIL outcome. More than 30% of the patients had intolerance to certain foods.

CONCLUSION

Obese patients undergoing RYGB can establish a postoperative lifestyle and diet similar to the ideal. Only the daily amount of ingested calories demonstrated a statistically significant influence on weight loss over time.

Outcome of laparoscopic adjustable gastric banding and prevalence of band revision and explantation at academic centers: 2007-2009

BACKGROUND

Laparoscopic adjustable gastric banding is gaining in popularity in the United States. Our objective was to examine the outcomes of laparoscopic adjustable gastric banding and the prevalence of band revision and explantation at academic medical centers.

METHODS

Using the "International Classification of Diseases, 9th revision," diagnosis and procedure codes, data were obtained from the University Health System Consortium Clinical Database for all laparoscopic adjustable gastric banding procedures performed from 2006 to 2009. The outcome measures included demographics, length of hospital stay, perioperative morbidity, mortality, and the prevalence of band revision and explantation.

RESULTS

A total of 10,151 laparoscopic gastric banding procedures were performed from January 2007 to December 2009. The mean length of stay was 1.2 days. The perioperative morbidity rate was 3.0%, and the in-hospital mortality rate was .03%. The prevalence of band revision was .76% and of band explantation was .87%. Compared with the outcome of primary gastric banding, gastric band revision or explantation was associated with a longer length of hospital stay, greater perioperative morbidity, and greater cost.

CONCLUSION

Within the context of the 3-year period of analysis, laparoscopic gastric banding was associated with low perioperative morbidity and mortality and a low prevalence of band revision and explantation.

'A beautiful show of strength': weight loss and the fat activist self

This article explores the disciplinary and productive effects of late 20th-century/early 21st-century discourse around the obesity epidemic. For my purposes, both the Fat Activist and Weight Loss Surgery patient may be seen as outcomes of this discursive proliferation. Based on a content analysis of two online accounts of weight loss by prominent fat activists, I examine the ways in which such public declarations can be seen as contemporary examples of Foucault's notion of the confession. Through debates in the 'fatosophere', such activists and their peers simultaneously take up and reject both biomedical and fat activists tenets in ways that are highly ambivalent. In the process, fat activism unsettles and resituates its borders and boundaries and the issue of weight loss becomes a discursive technique of knowledge/power for the understanding of and relating to the fat activist self.

Long-term weight loss maintenance in the United States

CONTEXT

Although the rise in overweight and obesity in the United States is well documented, long-term weight loss maintenance (LTWLM) has been minimally explored.

OBJECTIVE

The aim of this study is to estimate the prevalence and correlates of LTWLM among US adults.

DESIGN, SETTING AND PARTICIPANTS

We examined weight data from 14 306 participants (age 20-84 years) in the 1999-2006 National Health and Nutrition Examination Survey (NHANES). We defined LTWLM as weight loss maintained for at least 1 year. We excluded individuals who were not overweight or obese at their maximum weight.

RESULTS

Among US adults who had ever been overweight or obese, 36.6, 17.3, 8.5 and 4.4% reported LTWLM of at least 5, 10, 15 and 20%, respectively. Among the 17.3% of individuals who reported an LTWLM of at least 10%, the average and median weight loss maintained was 19.1 kg (42.1 pounds) and 15.5 kg (34.1 pounds), respectively. LTWLM of at least 10% was higher among adults of ages 75-84 years (vs ages 20-34, adjusted odds ratio (OR): 1.5; 95% confidence interval (CI): 1.2, 1.8), among those who were non-Hispanic white (vs Hispanic, adjusted OR: 1.6; 95% CI: 1.3, 2.0) and among those who were female (vs male, adjusted OR: 1.2; 95% CI: 1.1, 1.3).

CONCLUSIONS

More than one out of every six US adults who has ever been overweight or obese has accomplished LTWLM of at least 10%. This rate is significantly higher than those reported in clinical trials and many other observational studies, suggesting that US adults may be more successful at sustaining weight loss than previously thought.

Congruence between clinical and research-based psychiatric assessment in bariatric surgical candidates

BACKGROUND

Mental health professionals have become increasingly involved in working with bariatric surgical candidates, particularly in performing preoperative psychological evaluations to clear candidates for surgery. The objective of the present study was to examine the concordance of the psychiatric diagnoses obtained during routine clinical evaluation before bariatric surgery and the diagnoses obtained separately at a research facility using the Structured Clinical Interview for DSM (Diagnostic and Statistical Manual of Mental Disorders)-IV axis I disorders.

METHODS

The study included 68 consecutively enrolled bariatric surgical candidates who had participated in the Longitudinal Assessment of Bariatric Surgery-3 study. The Structured Clinical Interview for DSM disorders data obtained from the research assessments were compared with the diagnostic data from the routine preoperative psychiatric evaluations. The congruence of the current and lifetime diagnoses was assessed using Cohen's coefficient kappa.

RESULTS

Considerable variability was found among the major diagnostic categories, with generally poor agreement found for the current diagnoses. The kappa coefficients tended to be larger for the lifetime diagnoses. The agreement was moderate for any lifetime mood disorder, with a kappa value of 0.45. Regarding any lifetime anxiety, substance use, and eating disorder, the clinical diagnoses rarely concurred with the results from the Structured Clinical Interview for DSM disorders, with a kappa statistic of 0.30, 0.36, and 0.32, respectively.

CONCLUSION

The congruence between the diagnoses assigned during the routine clinical psychiatric evaluations and research assessment using the Structured Clinical Interview for DSM disorders was surprisingly low. These conclusions should be considered tentative, given the interval and the possibility of treatment having occurred between the 2 evaluations. Overall, these data raise interesting questions concerning the use of unstructured psychiatric evaluations before bariatric surgery.

Exercise, fluid, and nutrition recommendations for the postgastric bypass exerciser

To review the literature for nutritional, fluid, and exercise recommendations in patients who have undergone bariatric surgery.

DATA SOURCES

PubMed (1980 - October 2008). The bibliographies of selected literature were reviewed for additional sources. A systematic review of the literature is presented. There is little high-quality evidence to support any recommendations currently. Most recommendations are expert opinion. Nutritional deficiencies are common. Routine screening and nutrient replacement is adequate for most deficiencies. Increased physical activity before surgery is associated with improved quality of life. Walking is adequate as a primary activity after surgery. Pedometers may serve as a useful tool to help guide exercise recommendations. There is need for further research upon specific exercise recommendations.

The impact of socioeconomic factors on patient preparation for bariatric surgery

BACKGROUND

Socioeconomic factors (SEF) influence bariatric surgery access and outcomes perhaps because of variations in patient knowledge and behaviors. This study examines the associations between income, formal education, race, health insurance, employment status, and patient self-educational and behavioral activities prior to bariatric surgery.

METHODS

From March 2005 through January 2006, we surveyed 127 individuals who contacted our office seeking bariatric surgery. Study participants were asked to report their income, formal education, health insurance, employment status, height, weight, and standard demographic data. The type and number of self-educational resources utilized were elicited; a description of current eating and exercise behaviors was obtained; and an objective assessment (OA) of knowledge of the risks of both obesity and bariatric procedures was completed.

RESULTS

The most valuable self-educational resource cited by respondents was the internet (41.2%) and was unaffected by SEF. Individuals who were employed, privately insured, white, and earning>or=$20,000/year reported using a greater number of self-educational resources than their peers, while subjects who were privately insured, had higher formal educational levels, and earned>or=$20,000/year demonstrated greater proficiency on the OA instrument. Engagement in healthy eating and exercise behaviors was unaffected by any SEF. On multivariate analysis, higher income was the sole significant factor directly related to the number of educational resources utilized and proficiency on OA.

CONCLUSION

Obese patients from lower-income households may benefit from additional preoperative education. All individuals, regardless of socioeconomic factors, must be encouraged to implement healthy eating and exercise behaviors preoperatively.

Expert panel on weight loss surgery: executive report update

Rapid shifts in the demographics and techniques of weight loss surgery (WLS) have led to new issues, new data, new concerns, and new challenges. In 2004, this journal published comprehensive evidence-based guidelines on WLS. In this issue, we've updated those guidelines to assure patient safety in this fast-changing field. WLS involves a uniquely vulnerable population in need of specialized resources and ongoing multidisciplinary care. Timely best-practice updates are required to identify new risks, develop strategies to address them, and optimize treatment. Findings in these reports are based on a comprehensive review of the most current literature on WLS; they directly link patient safety to methods for setting evidence-based guidelines developed from peer-reviewed scientific publications. Among other outcomes, these reports show that WLS reduces chronic disease risk factors, improves health, and confers a survival benefit on those who undergo it. The literature also shows that laparoscopy has displaced open surgery as the predominant approach; that government agencies and insurers only reimburse procedures performed at accredited WLS centers; that best practice care requires close collaboration between members of a multidisciplinary team; and that new and existing facilities require wide-ranging changes to accommodate growing numbers of severely obese patients. More than 100 specialists from across the state of Massachusetts and across the many disciplines involved in WLS came together to develop these new standards. We expect them to have far-reaching effects of the development of health care policy and the practice of WLS.

Best practice updates for surgical care in weight loss surgery

To update evidence-based best practice guidelines for surgical care in weight loss surgery (WLS). Systematic search of English-language literature on WLS in MEDLINE, EMBASE, and the Cochrane Library between April 2004 and May 2007. Use of key words to narrow the search for a selective review of abstracts, retrieval of full articles, and grading of evidence according to systems used in established evidence-based models. Evidence-based best practice recommendations from the most recent literature on surgical methods and technologies, risks and benefits, outcomes, and surgeon qualifications and credentialing. We identified >135 articles; the 65 most relevant were reviewed in detail. Regular updates of evidence-based recommendations for best practices in WLS are required to address rapid changes in surgical techniques and patient demographics. Key factors in patient safety include surgical risk factors, type of procedure, surgeon training, and facility certification.

Alcohol abuse and dependence before and after bariatric surgery: a review of the literature and report of a new data set

BACKGROUND

To review the published data on alcohol abuse and alcohol dependence after bariatric surgery and to assess the prevalence of alcohol abuse and alcohol dependence in a sample of bariatric surgery patients, both before and after surgery. All participant data were collected from patients who had undergone gastric bypass at a Midwestern hospital.

METHODS

The participants were contacted by mail 6-10 years after surgery and asked to complete the Post-Bariatric Surgery Appearance Questionnaire.

RESULTS

The results of the analysis indicated that a small percentage of the sample appeared to spontaneously develop alcohol abuse or dependence after bariatric surgery.

CONCLUSION

The results of the present study will be useful in understanding the likelihood of bariatric surgery patients developing alcohol abuse and dependence after surgery. However, additional research is needed to fully understand the risk of this outcome.

Bariatric Operations in Veterans Affairs and Selected University Medical Centers: Results of the Patient Safety in Surgery Study

BACKGROUND

The objectives of this study were to evaluate outcomes and predictors of morbidity in patients undergoing Roux-en-Y gastric bypass (RYGB) during the Patient Safety in Surgery (PSS) Study.

STUDY DESIGN

National Surgical Quality Improvement Program data on PSS patients undergoing RYGB were analyzed for unadjusted and adjusted outcomes. Gender groups acted differently and were analyzed separately. Multivariable regression modeling was used to analyze hospital type as a predictor of risk. Stepwise logistic regression was performed to determine patient factors predictive of postoperative morbidity.

RESULTS

A total of 2,438 patients (2,064 private sector [PS], 374 Veterans Affairs [VA]) were identified for analysis. Adjusted odds ratio for postoperative morbidity for VA versus PS female patients was 1.14 (95% CI, 0.63-2.05), and for male patients 2.29 (95% CI, 1.28-4.10). Stepwise logistic regression showed that independent risk factors predictive of morbidity were open procedure, higher American Society of Anesthesiologists class, higher body mass index, diabetes, alcohol consumption, leukocytosis, SGOT > 40 U/L, smoking history, and older age. Importantly, male gender was not significant (p = 0.13) in the regression analysis. Subsequent and unrelated to this study, the VA has restructured its bariatric surgical program, including regionalization of centers, with a substantial lowering of associated mortality and morbidity.

CONCLUSIONS

The VA male subset showed higher risk-adjusted postoperative morbidity compared with the PS male subset. The VA and PS female subsets had equivalent risk-adjusted postoperative morbidity. A systematic approach to quality-improvement processes resulted in improved bariatric surgical outcomes in the VA. Male gender might not be an independent risk factor in RYGB patients.

Nursing Challenges in the Administration of Oral Antidepressant Medications in Gastric Bypass Patients

More than half of gastric bypass patients take antidepressants preoperatively, presenting some unique considerations with this patient population. The challenges associated with antidepressant medications are experienced both preoperatively and postoperatively. As the gastric bypass option becomes more readily used in the treatment of obesity, the requirement for understanding the effect of this procedure on any alteration of medications will become more clinically important. The purpose of this paper is to present an overview of the potential challenges in providing optimal patient care for the gastric bypass patient who is taking antidepressant medications.

Acute kidney injury after gastric bypass surgery

Gastric bypass surgery is a common treatment for morbid obesity. The presence of comorbid conditions and drugs that are used to treat them can adversely influence kidney function. Risk factors and outcomes of acute kidney injury (AKI) after gastric bypass surgery are not well understood, however. A total of 504 patients underwent gastric bypass between January 2003 and 2005. Primary outcome was AKI, defined as a > or =50% increase in serum creatinine relative to baseline or requirement of dialysis. Secondary outcomes were duration of hospitalization, all-cause hospital mortality, and readmissions within 30 d after surgery. Demographic, comorbid, and laboratory variables and preoperative medication use were examined as potential risk factors for AKI. A total of 42 (8.5%) patients developed postoperative AKI. Hyperlipidemia, preoperative use of angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin receptor blockers (ARB), intraoperative hypotension, and higher body mass index were associated with increased frequency of AKI. By multivariable analyses, the independent risk factors for AKI were body mass index (odds ratio [OR] 1.03; 95% confidence interval [CI] 1.00 to 1.06), hyperlipidemia (OR 2.53; 95% CI 1.21 to 5.28), and preoperative use of ACE-I or ARB (OR 2.06; 95% CI 1.05 to 4.04). The postoperative mortality was 0.45% (n = 2), both of whom had AKI. Duration of hospitalization was greater in patients with AKI versus no AKI (4.0 versus 2.7 d; P = 0.0003). Postoperative AKI is not infrequent after gastric bypass surgery. Certain comorbid conditions and their commonly prescribed treatments, ACE-I or ARB, are independently associated with increased risk for postoperative AKI.