Increased inflammatory low-density neutrophils in severe obesity and effect of bariatric surgery: Results from case-control and prospective cohort studies.

BACKGROUND: Low-density neutrophils (LDN) are increased in several inflammatory diseases and may also play a role in the low-grade chronic inflammation associated with obesity. Here we explored their role in obesity, determined their gene signatures, and assessed the effect of bariatric surgery. METHODS: We compared the number, function, and gene expression profiles of circulating LDN in morbidly obese patients (MOP, n=27; body mass index (BMI) > 40 Kg/m2) and normal-weight controls (NWC, n=20; BMI < 25 Kg/m2) in a case-control study. Additionally, in a prospective longitudinal study, we measured changes in the frequency of LDN after bariatric surgery (n=36) and tested for associations with metabolic and inflammatory parameters. FINDINGS: LDN and inflammatory markers were significantly increased in MOP compared to NWC. Transcriptome analysis showed increased neutrophil-related gene expression signatures associated with inflammation, neutrophil activation, and immunosuppressive function. However, LDN did not suppress T cells proliferation and produced low levels of reactive oxygen species (ROS). Circulating LDN in MOP significantly decreased after bariatric surgery in parallel with BMI, metabolic syndrome, and inflammatory markers. INTERPRETATION: Obesity increases LDN displaying an inflammatory gene signature. Our results suggest that LDN may represent a neutrophil subset associated with chronic inflammation, a feature of obesity that has been previously associated with the appearance and progression of co-morbidities. Furthermore, bariatric surgery, as an efficient therapy for severe obesity, reduces LDN in circulation and improves several components of the metabolic syndrome supporting its recognized anti-inflammatory and beneficial metabolic effects. FUNDING: This work was supported in part by grants from the National Institutes of Health (NIH; 5P30GM114732-02, P20CA233374 - A. Ochoa and L. Miele), Pennington Biomedical NORC (P30DK072476 - E. Ravussin & LSU-NO Stanley S. Scott Cancer Center and Louisiana Clinical and Translational Science Center (LACaTS; U54-GM104940 - J. Kirwan).

Duration of Nil Per Os is causal in hospital length of stay following laparoscopic bariatric surgery.

INTRODUCTION: A recent bariatric surgical study demonstrated an inverse relationship of intraoperative hydration with the incidence of extended hospital length of stay (ehLOS: >1 postoperative hospital day). In that study, a post hoc analysis of the preoperative duration of Nil Per Os (NPO) past midnight revealed a significant dose-response association on the incidence of ehLOS, with the lowest incidence (10-12 %) predicted within the 2-5-h NPO interval. As NPO is associated with a state of compensatory dehydration, the objectives of this study were to prospectively examine the role of decreasing preoperative NPO intervals on the incidence of ehLOS in a similar bariatric surgical population and to establish causality of this association. METHODS: Following IRB approval, 168 bariatric surgeries were analyzed following institution of a revised oral water ad libitum policy until 2 h prior to surgery on the incidence of ehLOS. The role of duration of NPO on the incidence of ehLOS was assessed by logistic fit graphs and misclassification rates on the two groups. A statistical process control chart monitored the efficacy of the revised NPO guidelines. RESULTS: There were statistically significant, but not clinical, differences in the incidences of histories of anemia, gastroesophageal reflux disease, previous percutaneous cardiac intervention/percutaneous transluminal coronary artery angioplasty, or preoperative albumin levels between the two groups. There were no perioperative pulmonary aspirations of gastric contents in either group. Following reduction of the oral hydration interval to ≥2 h, a 13-15 % incidence of ehLOS was observed within the 2-5-h NPO interval with similar misclassification rates observed between the two groups. CONCLUSIONS: Allowing bariatric patients access to ad libitum water for up to 2 h prior to surgery decreased the incidence of ehLOS. Comparison of the dose-response curves within the 2-5-h NPO intervals before and after introduction of the revised NPO guidelines was similar and confirms causality.

Role of intraoperative fluids on hospital length of stay in laparoscopic bariatric surgery: a retrospective study in 224 consecutive patients.

BACKGROUND: Studies are unclear regarding optimal intraoperative fluid management during laparoscopic bariatric surgery. The purpose of this 1-year study was to investigate the role of intraoperative fluid administration on hospital length of stay (hLOS) and postoperative complications in laparoscopic bariatric surgery. METHODS: Patient data analyzed included previously reported demographics, comorbidities, and intraoperative fluid administration on the duration of hLOS and incidence of postoperative complications. RESULTS: Logistic regression analysis of demographic and comorbidity variables revealed that BMI (P = 0.0099) and history of anemia (P = 0.0084) were significantly associated with hLOS (C index statistic, 0.7). Lower rates of intraoperative fluid administration were significantly associated with longer hLOS (P = 0.0005). Recursive partitioning observed that patients who received <1,750 ml of intraoperative fluids resulted in longer hLOS when compared to patients who received ≥ 1,750 ml (LogWorth = 0.5). When intraoperative fluid administration rates were defined by current hydration guidelines for major abdominal surgery, restricted rates (<5 ml/kg/h) were associated with the highest incidence of extended hLOS (>1 postoperative day) at 54.1 % when compared to 22.9 % with standard rates (5-7 ml/kg/h) and were lowest at 14.5 % in patients receiving liberal rates (>7 ml/kg/h) (P < 0.0001). Finally, lower rates of intraoperative fluid administration were significantly associated with delayed wound healing (P = 0.03). CONCLUSIONS: The amount of intravenous fluids administered during laparoscopic bariatric surgery plays a significant role on hLOS and on the incidence of delayed wound healing.

Association of obesity with risk of coronary heart disease: findings from the National Health and Nutrition Examination Survey, 1999-2006.

BACKGROUND: Obesity is a well-known risk factor for the development of coronary heart disease (CHD). The aim of the present study was to examine the differences in the 10-year CHD risk with increasing severity of obesity in men and women participating in the latest National Health and Nutrition Examination Survey. METHODS: Data from a representative sample of 12,500 U.S. participants in the National Health and Nutrition Examination Survey from 1999 to 2006 were reviewed. The Framingham risk score was calculated for men and women according to a body mass index (BMI) of <25.0, 25.0-29.9, 30.0-34.9, and ≥ 35.0 kg/m(2). RESULTS: The prevalence of those with hypertension increased with an increasing BMI, from 24% for a BMI <25.0 kg/m(2) to 54% for a BMI of ≥ 35.0 kg/m(2). The prevalence of an abnormal total cholesterol level (>200 mg/dL) increased from 40% for a BMI <25.0 kg/m(2) to 48% for a BMI of ≥ 35.0 kg/m(2). The 10-year CHD risk for men increased from 3.1% for a BMI <25.0 kg/m(2) to a peak of 5.6% for a BMI of 30.0-34.9 kg/m(2). The 10-year CHD risk for women increased from .8% for a BMI <25.0 kg/m(2) to a peak of 1.5% for a BMI of ≥ 35.0 kg/m(2). Both diabetes and hypertension were independent risk factors for an increasing CHD risk. CONCLUSIONS: The 10-year CHD risk, calculated using the Framingham risk score, substantially increased with an increasing BMI. An important implication from our findings is the need to implement surgical and medical approaches to weight reduction to reduce the effect of morbidity and mortality from CHD on the U.S. healthcare system.

Hospital volume is not a predictor of outcomes after gastrectomy for neoplasm.

Studies have shown conflicting data with regard to the volume and outcome relationship for gastrectomy. Using the University HealthSystem Consortium national database, we examined the influence of the hospital's volume of gastrectomy on outcomes at academic centers between 2004 and 2008. Outcome measures, including length of stay, 30-day readmission, morbidity, and in-hospital mortality, were compared among high- (13 or greater), medium- (6 to 12), and low-volume (five or less) hospitals. There were 10 high- (n = 593 cases), 36 medium- (n = 1076 cases), and 75 low-volume (n = 500 cases) hospitals. There were no significant differences between high- and low-volume hospitals with regard to length of stay, overall complications, 30-day readmission rate, and in-hospital mortality (2.4 vs 4.4%, respectively, P = 0.06). Despite the small number of gastrectomies performed at the low-volume hospitals, these same hospitals performed a large number of other types of gastric surgery such as gastric bypass for the treatment of morbid obesity (102 cases/year). Within the context of academic medical centers, lower annual volume of gastrectomy for neoplasm is not a predictor of poor outcomes which may be explained by the gastric operative experience derived from other types of gastric surgery.