Detailed perioperative risk among patients with extreme obesity undergoing nonbariatric general surgery

Association of High BMI With Morbidity and Mortality in Common Emergency General Surgery Procedures

INTRODUCTION

Emergency general surgery (EGS) patients are at increased risk for postoperative morbidity and mortality. Obesity is a risk factor for poor outcomes in this population. Our study aimed to explore the association of body mass index (BMI) with postoperative outcomes in patients requiring common EGS procedures.

METHODS

A retrospective review of the 2018-2020 National Surgical Quality Improvement Program database identified patients undergoing four common EGS procedures: large bowel resection, small bowel resection, cholecystectomy, and appendectomy. Patients were classified by BMI: normal weight (18.5-24.9 kg/m2), obesity classes I (30-34.9 kg/m2), II (35-39.9 kg/m2), III (40-49.9 kg/m2), and IV (≥50 kg/m2). Main outcomes of interest were major adverse event (MAE) and mortality.

RESULTS

From 2018 to 2020, a total of 82,540 patients underwent one of four common EGS procedures. On unadjusted analysis, obesity class IV had higher mortality rates compared to classes I-III (6.2% vs 3.1%, P < 0.001). Patients in obesity classes I-III had lower odds of MAE and death relative to those of normal weight. Compared to other patients with obesity, those in obesity class IV were at increased risk of MAE (odds ratio 1.27; 95% confidence interval 1.13-1.44) and death (odds ratio 1.69; 95% confidence interval 1.34-2.13).

CONCLUSIONS

Patients with varying degrees of obesity have different risk profiles following common EGS procedures. While patients in lower obesity classes had reduced odds of adverse outcomes, those with BMI ≥50 kg/m2 were particularly at greater risk for postoperative morbidity and mortality. This vulnerable population warrants further investigation and increased vigilance to ensure high-quality care.

Subcutaneous fat thickness predicts postoperative seroma following laparoscopic total extra-peritoneal hernioplasty

PURPOSE

Seroma formation is the most common cause of morbidity associated with laparoscopic inguinal hernia repair. This study aimed to examine the relationship between the thickness of subcutaneous fat (TSF) and the risk of postoperative seroma.

METHODS

We reviewed data from a prospective cohort of 229 male patients who underwent laparoscopic total extra-peritoneal (TEP) hernioplasty for indirect inguinal hernia between August 2018 and July 2021. The TSF was assessed using preoperative ultrasound images. The risk factors for postoperative seroma were determined using univariate and multivariate logistic regression models.

RESULTS

Postoperative seromas occurred in 26 patients (11.4%). The factors associated with postoperative seroma included longer hernia duration, larger hernia defects, extension into the scrotum, and greater TSF (P < 0.05). In multivariate analysis, a greater TSF was independently associated with a greater risk of postoperative seroma (per 1 mm: odd ratio [OR] 1.105, 95% confidence interval [CI] 1.048-1.165, P < 0.001; TSF ≥ 26.0 mm: OR 7.033, 95% CI 2.485-19.901, P < 0.001). Similar results were obtained in the subgroup analysis. The area under the curve of TSF for predicting seroma formation was 0.703 (95% CI 0.601-0.806).

CONCLUSION

Ultrasound-derived TSF may be a promising prognostic factor for postoperative seroma in patients undergoing laparoscopic TEP repair. Further validation is required and then this parameter can be used to improve decision-making process.

Addressing uncertainty about the role of structured lifestyle modification for metabolic surgery patients

There is good evidence that structured lifestyle modification programmes improve health in patients with metabolic and cardiovascular disorders, but there is no specific evidence that they improve outcomes in patients undergoing metabolic or obesity surgery. Despite expert consensus guidelines stating this fact, some healthcare systems still compel patients to participate in a structured lifestyle modification programme prior to metabolic or obesity surgery. There is a well-established need for individualised multidisciplinary dietetic and physical activity care for metabolic and obesity surgery patients, and the benefits of intentional weight loss prior to surgery are well proven, but these are distinct from potentially harmful requirements for patients to undertake compulsory structured lifestyle programmes of fixed duration, frequency and intensity, which may delay surgery and reinforce obesity stigma. A critical step in rejuvenating metabolic surgery is to reframe patient participation in structured lifestyle modification programmes as an opportunity for education and empowerment, not as an indicator of motivation or suitability for metabolic surgery. Large, well-designed and adequately powered clinical trials are needed to address uncertainties in the evidence base for these programmes. Given genuine equipoise, they will need to determine whether "surgery plus lifestyle" is superior to "surgery plus placebo". Moreover, they will need to determine the cost-effectiveness of these programmes and identify some of the factors giving rise to the substantial heterogeneity in responses to structured lifestyle modification.

Associations between body mass index and all-cause mortality: A systematic review and meta-analysis

Fasting insulin and c-reactive protein confound the association between mortality and body mass index. An increase in fat mass may mediate the associations between hyperinsulinemia, hyperinflammation, and mortality. The objective of this study was to describe the "average" associations between body mass index and the risk of mortality and to explore how adjusting for fasting insulin and markers of inflammation might modify the association of BMI with mortality. MEDLINE and EMBASE were searched for studies published in 2020. Studies with adult participants where BMI and vital status was assessed were included. BMI was required to be categorized into groups or parametrized as non-first order polynomials or splines. All-cause mortality was regressed against mean BMI squared within seven broad clinical populations. Study was modeled as a random intercept. β coefficients and 95% confidence intervals are reported along with estimates of mortality risk by BMIs of 20, 30, and 40 kg/m2 . Bubble plots with regression lines are drawn, showing the associations between mortality and BMI. Splines results were summarized. There were 154 included studies with 6,685,979 participants. Only five (3.2%) studies adjusted for a marker of inflammation, and no studies adjusted for fasting insulin. There were significant associations between higher BMIs and lower mortality risk in cardiovascular (unadjusted β -0.829 [95% CI -1.313, -0.345] and adjusted β -0.746 [95% CI -1.471, -0.021]), Covid-19 (unadjusted β -0.333 [95% CI -0.650, -0.015]), critically ill (adjusted β -0.550 [95% CI -1.091, -0.010]), and surgical (unadjusted β -0.415 [95% CI -0.824, -0.006]) populations. The associations for general, cancer, and non-communicable disease populations were not significant. Heterogeneity was very large (I2  ≥ 97%). The role of obesity as a driver of excess mortality should be critically re-examined, in parallel with increased efforts to determine the harms of hyperinsulinemia and chronic inflammation.

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/).

An Assessment of the Relationship Between BMI and Children Undergoing Surgical Procedures: A Retrospective Study

Background: While multiple studies have documented that obesity increases the risk of operative complications among adults, little data exist on how obesity impacts surgical outcomes among children. We aimed to determine if children with obesity have different postoperative outcomes than their peers. Methods: A retrospective chart review was conducted of 875 patients aged between 2 and 18 years who underwent surgery during 2018. Patients were stratified, based on BMI percentile for age, as having less than healthy weight (<5th percentile), healthy weight (5th-84th percentile), excess weight (85th-94th percentile), or obesity (≥95th percentile). Demographic information and data on medical comorbidities and postoperative complications were collected. All analyses were conducted using chi-square or Kruskal-Wallis testing. Results: Eighty-two patients were excluded due to lack of BMI data and 56 were excluded as they had below healthy weight. Of the remaining 737 patients, 475 (64.4%) had healthy weight, 124 (16.8%) had excess weight, and 138 (18.70%) had obesity. Children with obesity had more tonsillectomy/adenoidectomy (p < 0.01) and vascular access (p = 0.04) procedures compared with peers. Additionally, patients with obesity were more likely to have a pre-existing history of liver disease (p < 0.01) and more frequently developed postoperative wound dehiscence (p < 0.01). No other complications occurred more frequently among children with obesity. Conclusions: Children with obesity required more tonsillectomy/adenoidectomy and vascular access procedures. Wound dehiscence was the only complication that was associated with obesity. This suggests that children with obesity are not inherently more prone to experience surgical complications and therefore elective procedures should likely not be deferred until preoperative weight loss is achieved.

Operative and long-term oncologic outcomes of laparoscopic versus open major liver resection in patients with a high body mass index (> 25 kg/m2): a propensity score matching analysis

BACKGROUND

With the recent rapid increase in the prevalence of obesity, the number of obese patients requiring liver resection, including laparoscopy, has increased. Accordingly, evaluating the outcome of laparoscopic liver resection in obese patients is increasingly important. This study aimed to compare the safety and feasibility of laparoscopic major liver resection (LMR) and open major liver resection (OMR) in patients with a high body mass index (BMI > 25.0 kg/m²).

METHODS

We reviewed 521 patients with high BMI (> 25.0 kg/m²) who underwent major liver resection for various indications between January 2009 and November 2018 at Asan Medical Center. We performed 1:1 propensity score matching of the LMR and OMR groups, with 120 patients subsequently included in each group.

RESULTS

LMR was associated with lower blood loss and shorter postoperative hospital stays (p < 0.001). Although there was no significant difference in overall complications (p = 0.080), non-liver-specific complications were observed less frequently after LMR (p = 0.025). American Society of Anesthesiologists class > II, BMI > 30 kg/m², and malignancy were independent predictors of morbidity. In a subgroup analysis of patients with hepatocellular carcinoma, there was no significant difference between the two groups in overall survival (hazard ratio 0.225; 95% confidence interval 0.049-1.047; p = 0.057) and recurrence-free survival (hazard ratio 0.761; 95% confidence interval 0.394-1.417; p = 0.417).

CONCLUSIONS

Obesity should not be considered a contraindication for major liver resection using a laparoscopic approach; however, when applying this approach for resecting malignancies in patients with a BMI > 30 kg/m² and comorbid diseases, special attention should be paid to the possibility of complications.

The impact of obesity on surgical outcomes in patients undergoing emergency laparotomy for high-risk abdominal emergencies

BACKGROUND

Obesity has been shown to increase the rates of morbidity and occasionally mortality in patients undergoing nonbariatric elective surgery. However, little is known about the impact of obesity on outcomes after surgery for high-risk abdominal emergencies.

METHODS

A single-center retrospective evaluation of outcomes in high-risk abdominal emergency patients categorized by body mass index (BMI) was conducted. Patient demographics, comorbidities, and operative details were analyzed. Patients with normal weight (BMI 18.5-24.9) served as comparators. Multivariable linear and logistic regression analyses were performed to assess the impact of obesity on surgical outcomes.

RESULTS

In total, 886 patients with BMI < 18.5 (underweight; n = 50), 18.5-24.9 (normal weight; n = 306), 25-29.9 (overweight; n = 336) and ≥ 30 (obese; n = 194) based on the World Health Organization (WHO) weight classification criteria met the inclusion criteria. Compared to normal-weight patients, patients with overweight and obesity were older and more likely to be male. The rates of comorbidity (100% vs 91.2%, p =  < 0.0001), morbidity (77.8% vs 65.6%, p = 0.003), and in-hospital mortality (44.8% vs 30.4%, p = 0.001) were all higher in patients with obesity than in normal-weight patients. Patients with obesity had an increased intensive care unit length of stay (ICU LOS) (13 days vs 9 days, p = 0.019) and hospital LOS (21.4 days vs 18.1 days, p = 0.081) and prolonged ventilation (39.1% vs 19.6%, p = 0.003). As BMI deviated from the normal range, the morbidity and mortality rates increased incrementally, with the highest morbidity (87.9%) and mortality (54.5%) rates observed in morbidly obese patients (BMI ≥ 40).

CONCLUSIONS

Patients with obesity were the most likely to have coexisting conditions, experience postoperative complications, and die during the first admission following EL for high-risk abdominal emergencies.

Perioperative Challenges in Patients Transplanted with Livers from Extreme Obese Donors

The combination of rising rates of obesity and the shortage of deceased donor livers have forced the consideration of marginal liver donors in terms of body mass index (BMI) for liver transplantation (LT). To date, there are still conflicting data on the impact of donor obesity on post-LT outcomes. We analyzed all patients undergoing LT alone in the United States (US) from October 2005 through December 2019 using the United Network of Organ Sharing (UNOS) data set. We categorized donor BMI >40 kg/m² as extremely obese (EO). Primary endpoints included 30-day perioperative mortality and early graft loss (EGL) within 7 days. A subgroup analysis was performed for the EO donor group to assess how macrovesicular steatosis (MaS) >30% affects 30-day mortality and EGL within 7 days. A total of 72,616 patients underwent LT during the study period. The 30-day perioperative mortality was significantly higher in the EO donor group (P = 0.02). On multivariate analysis, recipients undergoing LT with EO donors had a 38% higher 30-day mortality risk (odds ratio [OR], 1.38; 95% confidence interval [CI], 1.21-1.69) and 53% increased risk of EGL (OR, 1.53; 95% CI, 1.22-1.90). MaS >30% was independently associated with a 2-fold increased risk of 30-day mortality (P = 0.003) and 3.5-fold increased risk of EGL within 7 days (P < 0.001). The impact of MaS >30% in EGL was 2-fold for all patients transplanted during the study period compared with 3.5-fold in the EO donor group. There is an increased risk of EGL and 30-day perioperative mortality in recipients transplanted with EO donors. Future studies are warranted in morbid and super obese donors to assess the possible effect of obesity-related proinflammatory factors in EGL.

Smoking, Obesity, and the Elective Operation

Smoking and obesity are commonly encountered problems in the elective, perioperative setting. This article reviews the risks posed by smoking and diabetes and explores way to mitigate such risks. Other means of perioperative optimization are also discussed in an effort to describe perioperative strategies that can improve patient outcomes.

Hepatic Steatosis is Associated with an Increased Risk of Postoperative Infections and Perioperative Transfusion Requirements in Patients Undergoing Hepatectomy

BACKGROUND

To determine the impact of hepatic steatosis on perioperative outcomes of patients undergoing hepatectomy.

METHODS

We analyzed all hepatectomy patients with normal and fatty liver texture, between 2014 and 2018 using NSQIP. Main endpoints included perioperative transfusions (within 72 h) and infectious complications.

RESULTS

A total of 8,237 patients underwent hepatectomy during the study period. The overall rate of fatty liver texture (FLG) was 31% (2,557). Operative duration was significantly longer; inflow occlusion was more common (Pringle maneuver), and the need of transfusions was significantly higher in the FLG compared to the normal liver group (NLG) (p =  < 0.001). On multivariate analysis, patients in the FLG had increased risk of developing infectious complications (OR 1.22 [95%IC 1.05-1.41]) and transfusion requirements within 72 h after hepatectomy (OR 1.43 [95% CI 1.24-1.63]).

CONCLUSIONS

Hepatic steatosis is an independent risk factor for the development of infectious complications and increased perioperative transfusion requirements in patients undergoing hepatectomy. Those requiring transfusions within 72 h had also an increased risk of infections after hepatectomy.

Structured Lifestyle Modification Prior to Bariatric Surgery: How Much is Enough?

Many healthcare systems require patients to participate in a structured lifestyle modification programme prior to bariatric surgery, even though bariatric consensus guidelines do not recommend this. While there is good evidence that such programmes improve health in other conditions such as metabolic and cardiovascular diseases, there is no evidence that they improve outcomes after bariatric surgery. The distinction needs to be drawn between the well-established need for individualised multidisciplinary dietetic and physical activity care for bariatric surgical patients and the potential harms from mandating participation in compulsory structured lifestyle programmes of fixed duration, frequency and intensity, which may delay surgery, reinforce obesity stigma, or both. Large clinical trials might help to address some of the uncertainty and provide an evidence base for clinicians and policymakers.

Differential Perioperative Outcomes in Patients With Obstructive Sleep Apnea, Obesity, or a Combination of Both Undergoing Open Colectomy: A Population-Based Observational Study

BACKGROUND

An increasing body of evidence demonstrates an association between obstructive sleep apnea (OSA) and adverse perioperative outcomes. However, large-scale data on open colectomies are lacking. Moreover, the interaction of obesity with OSA is unknown. This study examines the impact of OSA, obesity, or a combination of both, on perioperative complications in patients undergoing open colectomy. We hypothesized that while both obesity and OSA individually increase the likelihood for perioperative complications, the overlap of the 2 conditions is associated with the highest risk.

METHODS

Patients undergoing open colectomies were identified using the national Premier Healthcare claims-based Database (2006-2016; n = 340,047). Multilevel multivariable models and relative excess risk due to interaction (RERI) analysis quantified the impact of OSA, obesity, or both on length and cost of hospitalization, respiratory and cardiac complications, intensive care unit (ICU) admission, mechanical ventilation, and inhospital mortality.

RESULTS

Nine thousand twenty-eight (2.7%) patients had both OSA and obesity diagnoses; 10,137 (3.0%) had OSA without obesity; and 33,692 (9.9%) had obesity without OSA. Although there were overlapping confidence intervals in the binary outcomes, the risk increase was found highest for OSA with obesity, intermediate for obesity without OSA, and lowest for OSA without obesity. The strongest effects were seen for respiratory complications: odds ratio (OR), 2.41 (2.28-2.56), OR, 1.40 (1.31-1.49), and OR, 1.50 (1.45-1.56), for OSA with obesity, OSA without obesity, and obesity without OSA, respectively (all P < .0001). RERI analysis revealed a supraadditive effect of 0.51 (95% confidence interval [CI], 0.34-0.68) for respiratory complications, 0.11 (-0.04 to 0.26) for cardiac complications, 0.30 (0.14-0.45) for ICU utilization, 0.34 (0.21-0.47) for mechanical ventilation utilization, and 0.26 (0.15-0.37) for mortality in patients with both OSA and obesity, compared to the sum of the conditions' individual risks. Inhospital mortality was significantly higher in patients with both OSA and obesity (OR [CI], 1.21 [1.07-1.38]) but not in the other groups.

CONCLUSIONS

Both OSA and obesity are individually associated with adverse perioperative outcomes, with a supraadditive effect if both OSA and obesity are present. Interventions, screening, and perioperative precautionary measures should be tailored to the respective risk profile. Moreover, both conditions appear to be underreported compared to the general population, highlighting the need for stringent perioperative screening, documentation, and reporting.