Impact of obesity on postoperative and long-term outcomes in a general surgery population: a retrospective cohort study. World J Surg. 2013;37:2561-2568. [PMID: 23887596 DOI: 10.1007/s00268-013-2162-y]

The impact of body mass index on oncological and surgical outcomes of patients undergoing nephrectomy: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis to evaluate the impact of body mass index (BMI) on oncological (primary) and surgical (secondary) outcomes of patients who underwent nephrectomy, as obesity or high BMI is a known risk factor for renal cell carcinoma (RCC) and predictor of poorer outcomes.

METHODS

Studies were identified from four electronic databases from database inception to 2 June 2021, according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement. The review protocol was registered in the International Prospective Register of Systematic Reviews with the identification number: CRD42021275124.

RESULTS

A total of 18 studies containing 13 865 patients were identified for the final meta-analysis. Regarding oncological outcomes, higher BMI predicted higher overall survival (BMI >25 vs BMI <25 kg/m2 : hazard ratio [HR] 0.70, 95% confidence interval [CI] 0.58-0.85), cancer-specific survival (BMI >25 vs BMI <25 kg/m2 : HR 0.60, 95% CI 0.50-0.73; BMI 25-30 vs BMI <25 kg/m2 : HR 0.46, 95% CI 0.23-0.95; BMI >30 vs BMI <25 kg/m2 : HR 0.50, 95% CI 0.36-0.69), and recurrence-free survival rates (BMI >25 vs BMI <25 kg/m2 : HR 0.72, 95% CI 0.63-0.82; BMI 25-30 vs BMI <25 kg/m2 : HR 0.59, 95% CI 0.42-0.82). Those with a lower BMI fared better in surgical outcomes, such as operation time and warm ischaemic time, although the absolute difference was minimal and unlikely to be clinically significant. There was no difference between groups for length of hospital stay, intraoperative or postoperative complications, blood transfusion requirements, and conversion to open surgery.

CONCLUSION

Our study suggests that a higher BMI is associated with improved long-term oncological survival and similar perioperative outcomes as a lower BMI. More research into the underlying biological and physiological mechanisms will enable better understanding of the effect of BMI, beyond mere association, on post-nephrectomy outcomes.

Effect of obesity on perioperative outcomes following gastrointestinal surgery: meta-analysis

BACKGROUND

Obesity can pose perioperative challenges related to obesity-associated co-morbidities and technical factors. However, the true impact of obesity on postoperative outcomes is not well established and reports are conflicting. The aim was to perform a systematic review and meta-analysis to explore the effect of obesity on perioperative outcomes for general surgery procedures in distinct obesity subtypes.

METHODS

A systematic review was performed for studies reporting postoperative outcomes in relation to BMI in upper gastrointestinal, hepatobiliary and colorectal based on an electronic search using the Cochrane Library, Science Direct, PubMed and Embase up to January 2022. The primary outcome was the incidence of 30-day postoperative mortality among patients with obesity undergoing general surgical procedures in comparison to patients with normal range BMI.

RESULTS

Sixty-two studies, including 1 886 326 patients, were eligible for inclusion. Overall, patients with obesity (including class I/II/II) had lower 30-day mortality rates in comparison to patients with a normal BMI (odds ratio (OR) 0.75, 95 per cent c.i. 0.66 to 0.86, P < 0.0001, I2 = 71 per cent); this was also observed specifically in emergency general surgery (OR 0.83, 95 per cent c.i. 0.79 to 0.87, P < 0.0000001, I2 = 7 per cent). Compared with normal BMI, obesity was positively associated with an increased risk of 30-day postoperative morbidity (OR 1.11, 95 per cent c.i. 1.04 to 1.19, P = 0.002, I2 = 85 per cent). However, there was no significant difference in postoperative morbidity rates between the cohorts of patients with a normal BMI and class I/II obesity (OR 0.98, 95 per cent c.i. 0.92 to 1.04, P = 0.542, I2 = 92 per cent). Overall, the cohort with obesity had a higher rate of postoperative wound infections compared with the non-obese group (OR 1.40, 95 per cent c.i. 1.24 to 1.59, P < 0.0001, I2 = 82 per cent).

CONCLUSION

These data suggest a possible 'obesity paradox' and challenge the assumption that patients with obesity have higher postoperative mortality compared with patients with normal range BMI. Increased BMI alone is not associated with increased perioperative mortality in general surgery, highlighting the importance of more accurate body composition assessment, such as computed tomography anthropometrics, to support perioperative risk stratification and decision-making.

REGISTRATION NUMBER

CRD42022337442 (PROSPERO https://www.crd.york.ac.uk/prospero/).

Obesity Does Not Increase Perioperative Outcomes in Older Patients Undergoing Thoracoscopic Anatomic Lung Cancer Surgery

Objectives

To investigate the relationship between obesity status and perioperative outcomes in elderly patients undergoing thoracoscopic anatomic lung cancer surgery.

Methods

From January 2016 to December 2018, we performed a monocentric retrospective cohort study among 4164 consecutive patients aged 65 years or older who underwent thoracoscopic anatomic lung cancer surgery at Shanghai Chest Hospital. Two groups were stratified by body mass index (BMI): nonobese (BMI<28kg/m²) and obese status (BMI≥28kg/m²). Using a 1:1 propensity score matching (PSM) analysis to compare perioperative outcomes between two groups.

Results

4035 older patients were eventually enrolled, with a mean age of 69.8 years (range: 65-87), and 305 patients were eligible for obese status, with a mean BMI of 29.8 ± 1.7kg/m². Compared with nonobese patients, obese patients were more likely to have higher rates of intraoperative hypoxemia (1.2% vs 3.9%, P=0.001) and new-onset arrhythmia (2.3% vs 4.3%, P=0.034). The difference in intraoperative transfusion and conversion rates and postoperative outcomes regarding pulmonary complications, new-onset arrhythmia, transfusion, length of hospital stay, 30-day readmission and hospitalization costs between two groups were not significant (P>0.05). After a 1:1 PSM analysis, the difference in both intraoperative and postoperative complications among two groups were not significant (P>0.05). In subgroup analysis, patients with BMI≥30kg/m² had a similar incidence of perioperative complications compared to patients with BMI between 28 and 30 kg/m² (P>0.05).

Conclusions

Our research data support evidence for “obesity paradox” and also contribute the growing body of evidence that obesity in older patients should not exclude candidates for thoracoscopic anatomic lung cancer surgery.

Deep inferior epigastric perforator (DIEP) flap safety profile in slim versus non-slim BMI patients: A systematic review and meta-analysis

BACKGROUND/PURPOSE

The complications of breast reconstruction using deep inferior epigastric perforator (DIEP) flaps in non-slim patients are well recognized. However, the effects of this surgery performed on slim patients are yet to be consolidated. This study aims to compare the outcomes of performing DIEP flap breast reconstruction in slim and non-slim body mass index (BMI) patients.

METHODS

Meta-analysis was performed with a multi-database search (Cochrane, EMBASE, OVID Medline, PubMed, and Web of Sciences) according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines on 1 February 2021. Data from articles meeting inclusion criteria were extracted and analyzed with an inverse variance statistical model.

RESULTS

Seven studies were included, comprising 574 slim patients and 901 non-slim BMI patients who underwent autologous DIEP flap breast reconstruction. When comparing between the slim and non-slim groups, no statistically significant difference was found in terms of complete flap loss (OR=0.53, 95% CI: 0.11-2.68, p=0.44), partial flap loss (OR=0.92, 95% CI: 0.3-2.82, p=0.88), and fat necrosis (OR=0.91, 95% CI: 0.61-1.37, p=0.66). Similarly, in terms of general surgical complications, there was no statistically significant difference between groups in terms of all complications (OR=0.83, 95% CI: 0.45-1.51, p=0.54), abdominal wound healing complications (OR=1.01, 95% CI: 0.59-1.73, p=0.97), infections (OR=0.74, 95% CI: 0.41-1.37, p=0.34), and seroma (OR=0.89, 95% CI: 0.35-227, p=0.81).

CONCLUSION

There is no increased risk of postoperative complications in either group. DIEP flaps can be safely performed in slim patients, though higher quality research may be required to further confirm this.

The Association of Body Mass Index with Outcomes after Carotid Endarterectomy

BACKGROUND

Patients who are obese or underweight are traditionally at higher risk for perioperative morbidity and mortality. The effect of body mass index (BMI) on outcomes after carotid endarterectomy (CEA) is unclear. Our goal was to analyze the association of BMI with perioperative and long-term outcomes after elective CEA.

METHODS

The Vascular Quality Initiative (VQI) database was queried from 2003-2018 for patients undergoing elective CEAs. Patients were categorized into 5 BMI cohorts - underweight (UW, BMI < 18.5 kg/m²), normal weight (NW, BMI 18.5-24.9 kg/m²), overweight (OW, BMI 25-29.9 kg/m²), obese (OB, BMI 30-39.9 kg/m²), and morbidly obese (MO, BMI ≥ 40 kg/m²). Perioperative and long-term outcomes were assessed with univariable and multivariable analyses.

RESULTS

There were 89,079 patients included: 2% UW, 26% NW, 38.4% OW, 29.9% OB, and 3.6% MO. Overall, the mean age was 70.6 years, 60% were male, and 91.8% were of white race. There were significant differences among the BMI cohorts in regards to age, sex, smoking status, and comorbidities (all P < 0.05). For perioperative outcomes, the BMI cohorts differed significantly in reoperation for bleeding and 30-day mortality. On multivariable analysis, BMI was not associated with stroke or perioperative mortality. MO was associated with perioperative cardiac complications (Odds Ratios [OR] 1.26, 95% CI 1-1.57, P = 0.05). UW status was associated with increased return to the operating room (OR 1.89, 95% confidence interval [95% CI] 1.28-2.78, P = 0.001), 30-day mortality (OR 1.68, 95% CI 1-2.86, P =0.05), 1-year mortality (Hazard ratio [HR] 1.37, 95% CI 1.08-1.74, P = 0.01), and 5-year mortality (HR 1.22, 95% CI 1.06-1.41, P =0.005).

CONCLUSIONS

BMI status was not associated with perioperative stroke, cranial nerve injury, or surgical site infections. Patients with MO had higher perioperative cardiac complications. UW patients have lower short and long-term survival and should be a focus for long-term targeted risk factor stratification and modification.

Does morbid obesity influence perioperative outcomes after video-assisted thoracic surgery (VATS) lobectomy for non-small cell lung cancer? Analysis of the Italian VATS group registry

OBJECTIVES

Obesity in Europe, and worldwide, has been an increasing epidemic during the past decades. Moreover, obesity has important implications regarding technical issues and the risks associated with surgical interventions. Nevertheless, there is a lack of evidence assessing the influence of obesity on video-assisted thoracic surgery (VATS) lobectomy results. Our study aimed to assess the impact of morbid obesity on perioperative clinical and oncological outcomes after VATS lobectomy using a prospectively maintained nationwide registry.

METHODS

The Italian VATS lobectomy Registry was used to collect all consecutive cases from 55 Institutions. Explored outcome parameters were conversion to thoracotomy rates, complication rates, intra-operative blood loss, surgical time, hospital postoperative length of stay, chest tube duration, number of harvested lymph-node, and surgical margin positivity.

RESULTS

From 2016 to 2019, a total of 4412 patients were collected. 74 patients present morbid obesity (1.7%). Multivariable-adjusted analysis showed that morbid obesity was associated with a higher rate of complications (32.8% vs 20.3%), but it was not associated with a higher rate of conversion, and surgical margin positivity rates. Moreover, morbid obesity patients benefit from an equivalent surgical time, lymph-node retrieval, intraoperative blood loss, hospital postoperative length of stay, and chest tube duration than non-morbid obese patients. The most frequent postoperative complications in morbidly obese patients were pulmonary-related (35%).

CONCLUSION

Our results showed that VATS lobectomy could be safely and satisfactorily conducted even in morbidly obese patients, without an increase in conversion rate, blood loss, surgical time, hospital postoperative length of stay, and chest tube duration. Moreover, short-term oncological outcomes were preserved.

Isolated severe blunt traumatic brain injury: effect of obesity on outcomes

OBJECTIVE

Obesity has been widely reported to confer significant morbidity and mortality in both medical and surgical patients. However, contemporary data indicate that obesity may confer protection after both critical illness and certain types of major surgery. The authors hypothesized that this "obesity paradox" may apply to patients with isolated severe blunt traumatic brain injuries (TBIs).

METHODS

The Trauma Quality Improvement Program (TQIP) database was queried for patients with isolated severe blunt TBI (head Abbreviated Injury Scale [AIS] score 3-5, all other body areas AIS < 3). Patient data were divided based on WHO classification levels for BMI: underweight (< 18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), obesity class 1 (30.0-34.9 kg/m2), obesity class 2 (35.0-39.9 kg/m2), and obesity class 3 (≥ 40.0 kg/m2). The role of BMI in patient outcomes was assessed using regression models.

RESULTS

In total, 103,280 patients were identified with isolated severe blunt TBI. Data were excluded for patients aged < 20 or > 89 years or with BMI < 10 or > 55 kg/m2 and for patients who were transferred from another treatment center or who showed no signs of life upon presentation, leaving data from 38,446 patients for analysis. Obesity was not found to confer a survival advantage on univariate analysis. On multivariate analysis, underweight patients as well as obesity class 1 and 3 patients had a higher rate of mortality (OR 1.86, 95% CI 1.48-2.34; OR 1.18, 95% CI 1.01-1.37; and OR 1.41, 95% CI 1.03-1.93, respectively). Increased obesity class was associated with an increased risk of respiratory complications (obesity class 1: OR 1.19, 95% CI 1.03-1.37; obesity class 2: OR 1.30, 95% CI 1.05-1.62; obesity class 3: OR 1.55, 95% CI 1.18-2.05) and thromboembolic complications (overweight: OR 1.43, 95% CI 1.16-1.76; obesity class 1: OR 1.45, 95% CI 1.11-1.88; obesity class 2: OR 1.55, 95% CI 1.05-2.29) despite a decreased risk of overall complications (obesity class 2: OR 0.82, 95% CI 0.73-0.92; obesity class 3: OR 0.83, 95% CI 0.72-0.97). Underweight patients had a significantly increased risk of overall complications (OR 1.39, 95% CI 1.24-1.57).

CONCLUSIONS

Although there was an obesity-associated decrease in overall complications, the study data did not demonstrate a paradoxical protective effect of obesity on mortality after isolated severe blunt TBI. Obese patients with isolated severe blunt TBI are at increased risk of respiratory and venous thromboembolic complications. However, underweight patients appear to be at highest risk after severe blunt TBI, with significantly increased risks of morbidity and mortality.

Association of Obesity With Survival Outcomes in Patients With Cancer: A Systematic Review and Meta-analysis

Importance

Obesity, defined as a body mass index (BMI) greater than 30, is associated with a significant increase in the risk of many cancers and in overall mortality. However, various studies have suggested that patients with cancer and no obesity (ie, BMI 20-25) have worse outcomes than patients with obesity.

Objective

To assess the association between obesity and outcomes after a diagnosis of cancer.

Data Sources

PubMed, the Cochrane Library, and EMBASE were searched from inception to January 2020.

Study Selection

Studies reporting prognosis of patients with obesity using standard BMI categories and cancer were included. Studies that used nonstandard BMI categories, that were limited to children, or that were limited to patients with hematological malignant neoplasms were excluded. Screening was performed independently by multiple reviewers. Among 1892 retrieved studies, 203 (17%) met inclusion criteria for initial evaluation.

Data Extraction and Synthesis

The Meta-analysis of Observational Studies in Epidemiology (MOOSE) and Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines were reporting guideline was followed. Data were extracted by multiple independent reviewers. Risk of death, cancer-specific mortality, and recurrence were pooled to provide an adjusted hazard ratio (HR) with a 95% CI . A random-effects model was used for the retrospective nature of studies.

Main Outcomes and Measures

The primary outcome of the study was overall survival (OS) in patients with cancer, with and without obesity. Secondary end points were cancer-specific survival (CSS) and progression-free survival (PFS) or disease-free survival (DFS). The risk of events was reported as HRs with 95% CIs, with an HR greater than 1 associated with a worse outcome among patients with obesity vs those without.

Results

A total of 203 studies with 6 320 365 participants evaluated the association of OS, CSS, and/or PFS or DFS with obesity in patients with cancer. Overall, obesity was associated with a reduced OS (HR, 1.14; 95% CI, 1.09-1.19; P < .001) and CSS (HR, 1.17; 95% CI, 1.12-1.23; P < .001). Patients were also at increased risk of recurrence (HR, 1.13; 95% CI, 1.07-1.19; P < .001). Conversely, patients with obesity and lung cancer, renal cell carcinoma, or melanoma had better survival outcomes compared with patients without obesity and the same cancer (lung: HR, 0.86; 95% CI, 0.76-0.98; P = .02; renal cell: HR, 0.74; 95% CI, 0.53-0.89; P = .02; melanoma: HR, 0.74; 95% CI, 0.57-0.96; P < .001).

Conclusions and Relevance

In this study, obesity was associated with greater mortality overall in patients with cancer. However, patients with obesity and lung cancer, renal cell carcinoma, and melanoma had a lower risk of death than patients with the same cancers without obesity. Weight-reducing strategies may represent effective measures for reducing mortality in these patients.

The Association Between BMI and Mortality in Surgical Patients

BACKGROUND

While obesity is commonly associated with increased morbidity and mortality, in patients with chronic diseases, it has have been associated with a better prognosis, a phenomenon known as the 'obesity paradox'.

OBJECTIVE

We investigated the relationship between mortality, length of hospital stay (LOHS), and body mass index (BMI) in patients hospitalized to general surgical wards.

METHODS

We extracted data of patients admitted to the hospital between January 2011 and December 2017. BMI was classified according to the following categories: underweight (< 18.5), normal weight (18.5-24.9), overweight (25-29.9), obesity (30-34.9) and severe obesity (≥ 35). Main outcomes were mortality at 30-day mortality and at the end-of-follow-up mortality), as well as LOHS.

RESULTS

A total of 27,639 patients (mean age 55 ± 20 years; 48% males; 19% had diabetes) were included in the study. Median LOHS was longer in patients with diabetes vs. those without diabetes (4.0 vs 3.0 days, respectively), with longest LOHS among underweight patients. A 30-day mortality was 2% of those without (371/22,297) and 3% of those with diabetes (173/5,342). In patients with diabetes, 30-day mortality risk showed a step-wise decrease with increased BMI: 10% for underweight, 6% for normal weight, 3% for overweight, 2% for obese and only 1% for severely obese patients. In patients without diabetes, 30-day mortality was found to be 6% for underweight, 3% for normal weight and 1% across the overweight and obese categories. Mortality rate at the end-of-follow-up was 9% of patients without diabetes and 18% of those with diabetes (adjusted OR = 1.3, 95% CI, 1.2-1.5). In patients with diabetes, mortality risk showed an inverse association with respect to BMI: 52% for underweight, 29% for normal weight, 17% for overweight, 14% for obesity and 7% for severely obese patients, with similar trend in patients without diabetes.

CONCLUSIONS

The results support the 'obesity paradox' in the general surgical patients as those with and without diabetes admitted to surgical wards, BMI had an inverse association with short- and long-term mortality.

The effect of body mass index on outcomes following severe blunt chest trauma

INTRODUCTION

Obesity has been described as a significant risk factor for adverse outcomes in hospitalized patients. However, recent literature reports an "obesity paradox", suggesting that obesity may have a protective effect in a subset of surgical and critically ill patients. The present study assesses the effect of body mass index (BMI) on outcomes following severe isolated blunt chest trauma.

METHODS

This was a TQIP database study including patients with severe isolated blunt chest injury (chest AIS 3-5, extrathoracic AIS <3). Patients were excluded for age <20 or >89, death on arrival, facility transfer, or BMI <10 or >55. Patients were divided into five groups according to BMI: underweight (BMI <18.5), normal weight (18.5-24.9), overweight (25.0-29.9), obesity class 1 (30.0-34.9), obesity class 2 (35.0-39.9) and obesity class 3 (≥40.0). Logistic regression models were constructed to evaluate the effect of BMI on outcomes.

RESULTS

28,820 patients met criteria for inclusion in the analysis. After multivariable analysis, underweight patients as well as obesity class 2 and 3 patients had a significantly higher mortality (OR 1.86 [95% CI, 1.12-3.10], OR 1.48 [95% CI, 1.02-2.16], and OR 1.60 [95% CI, 1.03-2.50]), respectively. Underweight patients had significantly higher risk of overall complications as compared to normal weight patients (OR 1.58 [95% CI, 1.34-1.88]). Obesity class 2 and 3 were independently associated with increased respiratory complications (OR 1.60 [95% CI, 1.27-2.01] and OR 1.58 [95% CI, 1.20-2.09], respectively) and all classes of overweight and obese patients were associated with increased risk of VTE complications (OR 1.68 [95% CI, 1.23-2.27], OR 1.98 [95% CI, 1.42-2.77], OR 2.32 [95% CI, 1.55-3.48], OR 2.02 [95% CI, 1.23-3.33], respectively for overweight and obesity class 1, 2, 3).

CONCLUSIONS

The obesity paradox does not extend to severe blunt chest trauma. Underweight and obesity class 2 and 3 patients have worse mortality than normal weight patients. Obesity was independently associated with an increased risk of pulmonary and VTE complications.

Preoperative Evaluation Before Noncardiac Surgery

The medical complexity of surgical patients is increasing and medical specialties are frequently asked to assist with the perioperative management surgical patients. Effective pre-anesthetic medical evaluations are a valuable tool in providing high-value, patient-centered surgical care and should systematically address risk assessment and identify areas for risk modification. This review outlines a structured approach to the pre-anesthetic medical evaluation, focusing on the asymptomatic patient. It discusses the evidence supporting the use of perioperative risk calculation tools and focused preoperative testing. We also introduce important key topics that will be explored in greater detail in upcoming reviews in this series.

The BMI Paradox and Robotic Assisted Partial Nephrectomy

Introduction: Partial nephrectomy (PN), has become the gold standard for the surgical management of small renal masses, due to excellent oncologic control with concomitant preservation of nephron units. However, data regarding the association of obesity with perioperative outcomes following PN are mixed. Therefore, the association between obesity (using BMI) and post-operative complications (POC) rate following Robotic assisted laparoscopic PN (RPNx) was tested.

Methods: Two hundred and fifty-one adult patients who underwent RPNx from 1/2011 to 5/2017 at a single institution, with at least 90 days follow-up were identified and included. No patients were excluded. Electronic medical records were reviewed to record all POC within 90 days of surgery. A piecewise generalized linear model for binary outcomes (logistic) was used to model the proportion of subjects with POC by their BMI. The slope of the line is adjusted to a BMI of 30 Kg/m².

Results: BMI is significantly associated with POC rate. POC rate decreased with increasing BMI below the inflection point of 30 Kg/m² (0.848[0.756, 0.952]) (OR [95% CI], p = 0.005). POC rate was found to increase with increasing BMI above the BMI inflection of 30 Kg/m² (1.102 [1.027, 1.182], p = 0.0071).

Conclusions: In this cohort study, BMI showed an association with PC. It may be important to take BMI into account in surgical and clinical management considerations of RPNx, since higher rates of POC are associated with patients who are underweight, morbidly obese, and even with normal BMI. Further research is required on larger cohorts of RPNx patients to provide better description of this phenomenon and elucidate the role of BMI in development of POC.

Influence of the body mass index on postoperative outcome and long-term survival after pancreatic resections in patients with underlying malignancy

Background

While the long-term survival rate among patients with pancreatic and periampullary carcinomas remains low, it can be influenced by various factors. The purpose of this retrospective study was to investigate the effects of body mass index (BMI) on postoperative complications and patient survival after pancreatic resections for underlying malignancy over a 20-year observation period.

Methods

We analyzed 1,384 patients, 918 patients with pancreatic ductal adenocarcinoma (PDAC) (66.3%), 229 patients with distal cholangiocarcinoma (16.5%), 206 ampullary carcinoma patients (14.8%), and 31 duodenal carcinoma patients (2.2%). Patients were classified into four groups (group 1 <18.5; group 2, 18.5-25.0; group 3, 25.1-30.0; group 4 >30.0) according to their BMI (kg/m²). We analyzed differences in postoperative complications, postoperative length of hospital stays, reoperations, postoperative mortality and survival rate among the groups.

Results

Within a mean observation period of 687.7 [2-8,500] days, 735 (53.1%) patients died. There were important differences in postoperative complications (group 1, 16.2%; group 2, 20.3%; group 3, 27.2%, group 4, 41.6%) with the type of postoperative complications also varying between the groups. Overall 1-, 5-, 10- and 15-year survival rates were 66.4%, 25.5%, 17.9%, and 12.1%, respectively, with survival rates varying amongst the four groups.

Conclusions

Patients with a BMI between 18.5 and 30 show better postoperative outcomes, regarding complications, hospitalization duration, and reoperation rates than underweight or obese patients. Short-term survival depends strongly on postoperative complications while patients with a higher BMI show better long-term survival rates.

Reuniting overnutrition and undernutrition, macronutrients, and micronutrients

Over-nutrition and its late consequences are a dominant theme in medicine today. In addition to the health hazards brought on by over-nutrition, the medical community has recently accumulated a roster of health benefits with obesity, grouped under "obesity paradox." Throughout the world and throughout history until the 20^th century, under-nutrition was a dominant evolutionary force. Under-nutrition brings with it a mix of benefits and detriments that are opposite to and continuous with those of over-nutrition. This continuum yields J-shaped or U-shaped curves relating body mass index to mortality. The overweight have an elevated risk of dying in middle age of degenerative diseases while the underweight are at increased risk of premature death from infectious conditions. Micronutrient deficiencies, major concerns of nutritional science in the 20^th century, are being neglected. This "hidden hunger" is now surprisingly prevalent in all weight groups, even among the overweight. Because micronutrient replacement is safe, inexpensive, and predictably effective, it is now an exceptionally attractive target for therapy across the spectrum of weight and age. Nutrition-related conditions worthy of special attention from caregivers include excess vitamin A, excess vitamin D, and deficiency of magnesium.

A perioperative care map improves outcomes in patients with morbid obesity undergoing major surgery

BACKGROUND

The surgical management of patients with morbid obesity (body mass index ≥ 40) is notable for a relatively high risk of complications. To address this problem, a perioperative care map was developed using precautions and best practices commonly employed in bariatric surgery. It requires additional medical assessments, sleep apnea surveillance, more stringent guidelines for anesthetic management, and readily available bariatric operating room equipment, among other items. This care map was implemented in 2013 at 4 major urban teaching hospitals for use in patients undergoing all types of nonambulatory surgery with a body mass index greater than 40 kg/m². The impact on patient outcomes was evaluated.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was used to compare 30-day outcomes of morbidly obese patients before the year 2013 and after the years 2015 care-map implementation. In addition, trends in 30-day outcomes for morbidly obese patients were compared with those for non-obese patients.

RESULTS

Morbidly obese patients, between 2013 and 2015, saw an adjusted decrease in the rate of unplanned return to the operating room (OR = 0.49; P = .039), unplanned readmission (OR = 0.57; P = .006), total duration of stay (-0.87 days; P = .009), and postoperative duration of stay (-0.69 days; P = .007). Of these, total duration of stay (-0.86 days; P = .015), and postoperative duration of stay (-0.69 days; P = .012) improved significantly more for morbidly obese patients than for nonmorbidly obese patients.

CONCLUSION

Outcomes in morbidly obese patients improved from 2013 to 2015. Implementation of a perioperative care map may have contributed to these improvements. The care map should be further investigated and considered for more widespread use.

Impact of Obesity on Complications and 30-Day Readmission Rates After Cranial Surgery: A Single-Institutional Study of 224 Consecutive Craniotomy/Craniectomy Procedures

BACKGROUND

The prevalence of obesity is increasing at a disparaging rate in the United States. Although previous studies have associated obesity with increased surgical complications and readmission rates, the impact of obesity on surgical outcomes after cranial surgery remains understudied. The aim of this study is to assess the effect of obesity on complication and 30-day readmission rates after cranial surgery.

METHODS

The medical records of 224 consecutive patients (nonobese, n = 164; obese, n = 60) undergoing either craniotomy or craniectomy at a major academic institution in 2011 were reviewed. Preoperative body mass index equal to or greater than 30 kg/m² was classified as obese. The primary outcome investigated in this study was the rate of intraoperative and postoperative complications and 30-day readmissions after craniectomy/craniotomy.

RESULTS

Baseline patient characteristics and comorbidities were similar between the cohorts. The mean body mass indexes for both cohorts were significantly different (nonobese, 22.8 ± 4.2 kg/m² vs. obese, 45.1 ± 15.9 kg/m²; P < 0.0001). Most patients underwent tumor excision in both cohorts (nonobese, 64.0% vs. obese, 66.7%; P = 0.75). Compared with the nonobese cohort, the obese cohort had significantly higher estimated blood loss (nonobese, 209.9 ± 201.3 mL vs. obese, 284.9 ± 250.0 mL; P = 0.04), but similar length of operation (nonobese, 187.3 ± 89.4 minutes vs. obese, 209.6 ± 100.5; P = 0.14). Length of hospital stay and rate of postoperative complications were similar between both cohorts. Obese patients had increased rate of 30-day readmission, but this was not statistically significant (nonobese, 3.1% vs. obese, 6.7%; P = 0.25).

CONCLUSIONS

Our study suggests that obesity may not have a significant impact on surgical outcomes after cranial surgery.

Swedish surgical outcomes study (SweSOS): An observational study on 30-day and 1-year mortality after surgery

BACKGROUND

The European Surgical Outcomes Study (EuSOS) revealed large variations in outcomes among countries. In-hospital mortality and ICU admission rates in Sweden were low, going against the assumption that access to ICU improves outcome. Long-term mortality was not reported in EuSOS and is generally poorly described in the current literature.

OBJECTIVE

To describe the characteristics of the Swedish subset of EuSOS and identify predictors of short and long-term mortality after surgery.

DESIGN

An observational cohort study.

SETTING

Six universities and two regional hospitals in Sweden.

PATIENTS

A cohort of 1314 adult patients scheduled for surgery between 4 April and 11 April 2011.

MAIN OUTCOME MEASURES

30-day and 1-year mortality.

RESULTS

A total of 303 patients were lost to follow-up, leaving 1011 for analysis; 69% of patients were classified as American Society of Anesthesiologists' physical status 1 or 2, and 68% of surgical procedures were elective. The median length of stay in postanaesthesia care units (PACUs) was 175 min (interquartile range 110-270); 6.6% of patients had PACU length of stay of more than 12 h and 3.6% of patients were admitted to the ICU postoperatively. Thirty-day mortality rate was 1.8% [95% confidence interval (CI) 1.0-2.6] and 8.5% (CI 6.8-10.2) at 1 year (n = 18 and 86). The risk of death was higher than in an age and sex-matched population after 30 days (standardised mortality ratio 10.0, CI 5.9-15.8), and remained high after 1 year (standardised mortality ratio 3.9, CI 3.1-4.8). Factors predictive of 30-day mortality were age, American Society of Anesthesiologists' physical status, number of comorbidities, urgency of surgery and ICU admission. For 1-year mortality, age, number of comorbidities and urgency of surgery were independently predictive. ICU admission and long stay in PACU were not significant predictors of long-term mortality.

CONCLUSION

Mortality rate increased almost five-fold at 1 year compared with 30-day mortality after surgery, demonstrating a significantly sustained long-term risk of death in this surgical population. In Sweden, factors associated with long-term postoperative mortality were age, number of comorbidities and surgical urgency.

Obesity paradox, obesity orthodox, and the metabolic syndrome: An approach to unity

Obesity and the accompanying metabolic syndrome are strongly associated with heightened morbidity and mortality in older adults. In our review of more than 20 epidemiologic studies of major infectious diseases, including leaders such as tuberculosis, community-acquired pneumonia, and sepsis, obesity was associated with better outcomes. A cause-and-effect relationship between over-nutrition and survival with infection is suggested by results of two preliminary studies of infections in mice, where high fat feeding for 8-10 weeks provided much better outcomes. The better outcomes of infections with obesity are reminiscent of many recent studies of "sterile" non-infectious medical and surgical conditions where outcomes for obese patients are better than for their thinner counterparts --- and given the tag "obesity paradox". Turning to the history of medicine and biological evolution, we hypothesize that the metabolic syndrome has very ancient origins and is part of a lifelong metabolic program. While part of that program (the metabolic syndrome) promotes morbidity and mortality with aging, it helps infants and children as well as adults in their fight against infections and recovery from injuries, key roles in the hundreds of centuries before the public health advances of the 20th century. We conclude with speculation on how understanding the biological elements that protect obese patients with infections or injuries might be applied advantageously to thin patients with the same medical challenges.

Impact of body mass index on outcomes of 48281 patients undergoing first time cadaveric liver transplantation

AIM: To investigate possible disparities in perioperative morbidity and mortality among different body mass index (BMI) groups and to simulate the impact that these differences might have had on the cohort of patients undergoing cadaveric liver transplantation (LT).

METHODS: All adult recipients undergoing first time LT for benign conditions and receiving a whole graft from brain-dead donors were selected from the united network of organ sharing registry. From January 1994 to June 2013, 48281 patients satisfied the inclusion criteria and were stratified by their BMI. The hypothesis that abnormal BMIs were independent predictors of inferior outcomes was tested with univariate and multivariate regression analyses.

RESULTS: In comparison to normal weight recipients, underweight and morbidly obese recipients had increased 90-d mortality (adjusted OR = 1.737; 95%CI: 1.185-2.548, P = 0.005) (adjusted OR = 1.956; 95%CI: 1.473-2.597, P = 0.000) respectively and inferior patients’ survivals (adjusted HR = 1.265; 95%CI: 1.096-1.461, P = 0.000) (adjusted HR = 1.157; 95%CI: 1.031-1.299, P = 0.013) respectively. Overall, patients’ 5-year survival were 73.9% for normal-weight, 71.1% for underweight, 74.0% for overweight, 74.4% for class I obese, 75.0% for class II obese and 71.5% for class III obese recipients. Analysis of hypothetical exclusion of underweight and morbidly obese patients from the pool of potential LT candidates would have improved the overall survival of the entire cohort by 2.7% (95%CI: 2.5%-3.6%).

CONCLUSION: Selected morbidly obese patients undergoing LT for benign conditions had 5-year survival rates clinically comparable to normal weight recipients. Impact analysis showed that exclusion of high-risk recipients (underweight and morbid obese patients) would not significantly improve the overall survival of the entire cohort of patients requiring LT.

Obesity Is Not Associated with Antimicrobial Treatment Failure for Intra-Abdominal Infection

BACKGROUND

Obesity and commonly associated comorbidities are known risk factors for the development of infections. However, the intensity and duration of antimicrobial treatment are rarely conditioned on body mass index (BMI). In particular, the influence of obesity on failure of antimicrobial treatment for intra-abdominal infection (IAI) remains unknown. We hypothesized that obesity is associated with recurrent infectious complications in patients treated for IAI.

METHODS

Five hundred eighteen patients randomized to treatment in the Surgical Infection Society Study to Optimize Peritoneal Infection Therapy (STOP-IT) trial were evaluated. Patients were stratified by obese (BMI ≥30) versus non-obese (BMI≥30) status. Descriptive comparisons were performed using Chi-square test, Fisher exact test, or Wilcoxon rank-sum tests as appropriate. Multivariable logistic regression using a priori selected variables was performed to assess the independent association between obesity and treatment failure in patients with IAI.

RESULTS

Overall, 198 (38.3%) of patients were obese (BMI ≥30) versus 319 (61.7%) who were non-obese. Mean antibiotic d and total hospital d were similar between both groups. Unadjusted outcomes of surgical site infection (9.1% vs. 6.9%, p = 0.36), recurrent intra-abdominal infection (16.2% vs. 13.8, p = 0.46), death (1.0% vs. 0.9%, p = 1.0), and a composite of all complications (25.3% vs. 19.8%, p = 0.14) were also similar between both groups. After controlling for appropriate demographics, comorbidities, severity of illness, treatment group, and duration of antimicrobial therapy, obesity was not independently associated with treatment failure (c-statistic: 0.64).

CONCLUSIONS

Obesity is not associated with antimicrobial treatment failure among patients with IAI. These results suggest that obesity may not independently influence the need for longer duration of antimicrobial therapy in treatment of IAI versus non-obese patients.

Association between high visceral fat area and postoperative complications in patients with Crohn's disease following primary surgery

AIM

The aim of this study was to determine the association between visceral fat area (VFA) on CT and postoperative complications after primary surgery in patients with Crohn's disease (CD).

METHOD

Inclusion criteria were patients with a confirmed diagnosis of CD who had preoperative abdominal CT scan. The areas of total fat, subcutaneous fat and visceral fat were measured using an established image-analysis method at the lumbar 3 (L3) level on CT cross-sectional images. Visceral obesity was defined as a visceral fat area (VFA) of ≥ 130 cm(2) . Clinical variables, intra-operative outcomes and postoperative courses within 30 days were analysed.

RESULTS

A total of 164 patients met the inclusion criteria. Sixty-three (38.4%) patients had postoperative complications. The mean age of the patients with complications (the study group) was 40.4 ± 15.4 years and of those without complications (the control group) was 35.8 ± 12.9 years (P = 0.049). There were no differences in disease location and behaviour between patients with or without complications (P > 0.05). In multivariable analysis, VFA [odds ratio (OR) = 2.69; 95% confidence interval (CI): 1.09-6.62; P = 0.032] and corticosteroid use (OR = 2.86; 95% CI: 1.32-6.21; P = 0.008) were found to be associated with postoperative complications. Patients with visceral obesity had a significantly longer operative time (P = 0.012), more blood loss (P = 0.019), longer bowel resection length (P = 0.003), postoperative ileus (P = 0.039) and a greater number of complications overall (P < 0.001).

CONCLUSION

High VFA was found to be associated with an increased risk for 30-day postoperative complications in patients with CD undergoing primary surgery.

Nitrous Oxide and Serious Long-term Morbidity and Mortality in the Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA)-II Trial

Background

The Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA)-II trial randomly assigned 7,112 noncardiac surgery patients at risk of perioperative cardiovascular events to 70% N2O or 70% N2 groups. The aim of this follow-up study was to determine the effect of nitrous oxide on a composite primary outcome of death and major cardiovascular events at 1 yr after surgery.

Methods

One-year follow-up was conducted via a medical record review and telephone interview. Disability was defined as a Katz index of independence in activities of daily living score less than 8. Adjusted odds ratios and hazard ratios were calculated as appropriate for primary and secondary outcomes.

Results

Among 5,844 patients evaluated at 1 yr, 435 (7.4%) had died, 206 (3.5%) had disability, 514 (8.8%) had a fatal or nonfatal myocardial infarction, and 111 (1.9%) had a fatal or nonfatal stroke during the 1-yr follow-up period. Exposure to nitrous oxide did not increase the risk of the primary outcome (odds ratio, 1.08; 95% CI, 0.94 to 1.25; P = 0.27), disability or death (odds ratio, 1.07; 95% CI, 0.90 to 1.27; P = 0.44), death (hazard ratio, 1.17; 95% CI, 0.97 to 1.43; P = 0.10), myocardial infarction (odds ratio, 0.97; 95% CI, 0.81 to 1.17; P = 0.78), or stroke (odds ratio, 1.08; 95% CI, 0.74 to 1.58; P = 0.70).

Conclusion

These results support the long-term safety of nitrous oxide administration in noncardiac surgical patients with known or suspected cardiovascular disease.

The impact of hyperglycemia and obesity on hospitalization costs and clinical outcome in general surgery patients

BACKGROUND

The impact of obesity on clinical outcomes and hospitalization costs in general surgery patients with and without diabetes (DM) is unknown.

MATERIALS AND METHODS

We reviewed medical records of 2451 patients who underwent gastrointestinal surgery at two university hospitals. Hyperglycemia was defined as BG ≥140 mg/dl. Overweight was defined by body mass index (BMI) between 25-29.9 kg/m(2) and obesity as a BMI ≥30 kg/m(2). Hospital cost was calculated using cost-charge ratios from Centers for Medicare and Medicaid Services. Hospital complications included a composite of major cardiovascular events, pneumonia, bacteremia, acute kidney injury (AKI), respiratory failure, and death.

RESULTS

Hyperglycemia was present in 1575 patients (74.8%). Compared to patients with normoglycemia, those with DM and non-DM with hyperglycemia had higher number of complications (8.9% vs. 35.8% vs. 30.0%, p<0.0001), longer hospital stay (5 days vs. 9 days vs. 9 days, p<0.0001), more readmissions within 30 days (9.3% vs. 18.8% vs. 17.2%, p<0.0001), and higher hospitalization costs ($20,273 vs. $79,545 vs. $72,675, p<0.0001). In contrast, compared to normal-weight subjects, overweight and obesity were not associated with increased hospitalization costs ($58,313 vs. $58,173 vs. $66,633, p=0.74) or risk of complications, except for AKI (11.9% vs. 14.8% vs. 20.5%, p<0.0001). Multivariate analysis revealed that DM (OR=4.4, 95% CI=2.8,7.0) or perioperative hyperglycemia (OR=4.1, 95% CI=2.7-6.2) were independently associated with increased risk of complications.

CONCLUSION

Hyperglycemia but not increasing BMI, in patients with and without diabetes undergoing gastrointestinal surgery was associated with a higher number of complications and hospitalization costs.

Obesity--a risk factor for postoperative complications in general surgery?

Background

Obesity is generally believed to be a risk factor for the development of postoperative complications. Although being obese is associated with medical hazards, recent literature shows no convincing data to support this assumption. Moreover a paradox between body mass index and survival is described. This study was designed to determine influence of body mass index on postoperative complications and long-term survival after surgery.

Methods

A single-centre prospective analysis of postoperative complications in 4293 patients undergoing general surgery was conducted, with a median follow-up time of 6.3 years. We analyzed the impact of bodyweight on postoperative morbidity and mortality, using univariate and multivariate regression models.

Results

The obese had more concomitant diseases, increased risk of wound infection, greater intraoperative blood loss and a longer operation time. Being underweight was associated with a higher risk of complications, although not significant in adjusted analysis. Multivariate regression analysis demonstrated that underweight patients had worse outcome (HR 2.1; 95 % CI 1.4-3.0), whereas being overweight (HR 0.6; 95 % CI 0.5–0.8) or obese (HR 0.7; 95 % CI 0.6–0.9) was associated with improved survival.

Conclusion

Obesity alone is a significant risk factor for wound infection, more surgical blood loss and a longer operation time. Being obese is associated with improved long-term survival, validating the obesity paradox. We also found that complication and mortality rates are significantly worse for underweight patients. Our findings suggest that a tendency to regard obesity as a major risk factor in general surgery is not justified. It is the underweight patient who is most at risk of major postoperative complications, including long-term mortality.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-015-0096-7) contains supplementary material, which is available to authorized users.

Obesity-related immune responses and their impact on surgical outcomes

The obesity epidemic represents a critical disease burden with broad clinical consequences. At the same time, obesity has been linked to inferior surgical outcomes and considered a contraindication for some elective surgical procedures. A growing body of mechanistic evidence has accumulated linking obesity to changes of metabolism and immune responses. This concept provides an integrated inflammatory network based on the perception of obesity as a state of chronic low-grade inflammation. With a more detailed understanding of this dynamic network and mechanistic insights, novel treatment and management strategies may be developed with the goal to optimize surgical outcomes in obese patients.

[Obesity and lung cancer: incidence and repercussions on epidemiology, pathology and treatments]

INTRODUCTION

Obesity and lung cancer are major public health problems. The purpose of this work is to review the data concerning this association.

METHOD

We report clinical and epidemiological data on obesity and discuss the impact on the incidence of lung cancer, as well as the safety and efficiency of anti-tumor treatments.

RESULTS

Obesity does not contribute to the occurrence of lung cancer, unlike other malignancies. Patients may be more likely to undergo treatment at lower risk. Regarding surgery, obesity makes anaesthesia more difficult, increases the operative duration but does not increase postoperative morbidity and mortality. Chemotherapy and radiotherapy seem to be administered according to the same criteria as patients with normal weight. Paradoxically, survival rates of lung cancer are better in obese patients as well after surgery than after non-surgical treatment.

CONCLUSION

Obesity is related to many neoplasms but not to lung cancer. Regarding long-term survival all treatments combined, it has a favorable effect: this is the "obesity paradox".

Association of body mass index and outcomes after major lung resection

OBJECTIVES

Obesity has been thought to predispose patients to excess morbidity after lung resection because of decreased diaphragm excursion, reduced lung volumes and relative immobility. We assessed the relationship of body mass index (BMI) to acute outcomes after major lung resection.

METHODS

Information from our database of lung resections was evaluated for the period 1980-2011. Univariate analysis for adverse events (pulmonary, cardiovascular, other and overall) was used to select variables for inclusion in multivariate logistic regression analyses. Missing values were imputed. BMI was categorized as underweight (<18.5), normal (18.5-24.9), overweight (25-29.9), obese (30-34.9) and very obese (≥ 35).

RESULTS

Among 1369 patients, there were 703 males (51%) and the mean age was 62 ± 11 years. Complications included the following: pulmonary 12%, cardiovascular 15%, other 16%, mortality 5% and any 29%. The incidence of complications decreased during each decade of study (40, 30, 26, 20%; P < 0.0001) and the incidence of obese/very obese increased during the same intervals (11, 22, 30, 25%; P = 0.0007). Adjusting for age, performance status, coronary artery disease, smoking status, diffusing capacity of the lung for carbon monoxide, forced expiratory volume in 1 s and operation year, being overweight/obese/very obese did not increase the risk of postoperative complications in any category. In fact, patients in this group showed a lower rate of cardiovascular complications than those with BMI ≤ 25 (odds ratio (OR): 0.72; 95% confidence interval (CI): 0.51-1.00; P = 0.048). However, being underweight was importantly associated with an increased risk of pulmonary complications (OR: 2.5; 95% CI: 1.3-4.9; P = 0.0087) and of operative mortality (OR: 2.96; 95% CI: 1.28-6.86; P = 0.011).

CONCLUSION

Being overweight or obese does not increase the risk of complications after major lung resection. In contrast, patients who are underweight are at significantly increased risk of pulmonary complications and mortality. Knowledge of the relationship of BMI to perioperative risk for major lung resection is essential in proper risk stratification.