The relationship between body mass index and 30-day mortality risk, by principal surgical procedure

Weighing the outcomes: the role of BMI in complex robotic esophageal and hepatobiliary operations

BACKGROUND

The correlation between body mass index (BMI) and surgical outcomes has emerged as a critical consideration in complex abdominal operations. While elevated BMI is often associated with increased perioperative risk, its specific effects on the outcomes of robotic surgeries remain inadequately explored. This study assesses the impact of BMI on perioperative variables of complex esophageal and hepatopancreaticobiliary (HPB) robotic operations.

METHODS

Following IRB approval, we prospectively followed 607 patients undergoing pancreaticoduodenectomy, trans-hiatal esophagectomy (THE), major liver resection or distal pancreatectomy with splenectomy, all performed robotically. Perioperative data retrieved included operative duration, estimated blood loss (EBL), intraoperative and postoperative complications, conversions to an 'open' operation and length of stay (LOS). Z scores were assigned to each variable to standardize operations, and the variables were then regressed against BMI. For illustrative purposes, data are presented as median(mean ± standard deviation).

RESULTS

Between 2012 and 2020, surgeries included 71 THE, 122 distal pancreatectomies with splenectomies, 129 major hepatectomies and 285 pancreaticoduodenectomies. Median age was 67(65 ± 12.5) years old, and BMI was 27(28 ± 5.5) kg/m2. Operative duration for all operations was 349(355 ± 124.5) min and had a positive correlation with increasing BMI (p = 0.004), specifically for robotic THE and robotic pancreaticoduodenectomy, with both operative durations having positive correlation with increasing BMI (p = 0.02 and p = 0.05). No significant correlation with BMI was found for EBL, intraoperative or postoperative complications, conversion to 'open' surgery, or LOS.

CONCLUSION

Elevated BMI is associated with longer operative durations in select robotic surgeries, such as trans-hiatal esophagectomy and pancreaticoduodenectomy, and highlights the need for strategic planning in these patients.

A 5-year propensity-matched analysis of perioperative outcomes in patients with chronic kidney disease undergoing bariatric surgery

BACKGROUND

Bariatric surgery can improve renal function in patients with comorbid chronic kidney disease (CKD) and obesity. Additionally, bariatric surgery can enhance outcomes following renal transplantation. The safety of bariatric surgery in patients with CKD has been debated in the literature. This study evaluates the frequency of perioperative complications associated with CKD.

METHODS

The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database was queried from 2015-2019. Patients were included if they had a vertical sleeve gastrectomy (VSG) or Roux-en-Y gastric bypass (RYGB) and were stratified based on CKD status. An unmatched and propensity-matched analysis was performed comparing 30-day perioperative outcomes between the groups.

RESULTS

A total of 717,809 patients included in this study, 5817(0.8%) had CKD, of whom 2266(0.3%) were on dialysis. 74.3% of patients with CKD underwent VSG with 25.7% underwent RYGB. Comparing RYGB to VSG, patients who underwent RYGB had a higher rate of deep organ space infection (0.7%vs.0.1%,p = 0.021) and re-intervention (5.0% vs. 2.2%,p < 0.001). Within the VSG cohort, a matched analysis was performed for those with CKD and without CKD. The CKD cohort had higher risk of complications such as bleeding (2.1%vs. 0.9%,p < 0.001), readmission (9.3%vs.4.9%,p < 0.001), reoperation (2.7%vs.1.3%,p < 0.001), and need for reintervention (2.2%vs.1.3%,p < 0.001). Notably, patients with CKD also had a higher mortality (0.6%vs.0.2%,p = 0.003). No difference was seen between patients with renal insufficiency and patients on dialysis.

CONCLUSION

VSG has been the operation of choice in patients with CKD. Our results showed it is the safer option for patients with CKD compared to RYGB. Although this patient population does have an increased risk of adverse perioperative events, dialysis didn't affect the outcome. Bariatric surgeons who operate on patients with CKD should be well informed and remain vigilant given the increased perioperative risk. The risk is still considerably low, and the potential benefit on renal function and improvement in candidacy for renal transplant outweigh the risk. They should be considered as surgical candidates.

The Implications of Surgeon Case Volume and Hospital Volume on Outcomes of Aortobifemoral Bypasses in Obese Patients

BACKGROUND

Aortobifemoral (ABF) bypass is the gold standard for treating symptomatic aortoiliac occlusive disease. In the era of heightened interest in the length of stay (LOS) for surgical patients, this study aims to investigate the association of obesity with postoperative outcomes at the patient, hospital, and at surgeon levels.

METHODS

This study utilized the Society of Vascular Surgery (SVS) Vascular Quality Initiative (VQI) suprainguinal bypass database from 2003-2021. The selected study cohort was divided into obese patients (BMI ≥30) (Group I) and non-obese patients (BMI <30) (Group II). Primary outcomes of the study included mortality, operative time, and postoperative LOS. Univariate and multivariate logistic regression analyses were performed to study the outcomes of ABF bypass in Group I. Operative time, and postoperative LOS were transformed into binary values by median split for regression analysis. A p-value of ≤ 0.05 was deemed statistically significant in all the analyses of this study.

RESULTS

The study cohort consisted of 5,392 patients. In this population, 1,093 were obese (Group I), and 4,299 were non-obese (Group II). Group I was found to have more females with higher rates of comorbid conditions, including hypertension, diabetes mellitus, and congestive heart failure. Patients in Group I had increased odds of prolonged operative time (≥ 250 mins) and an increased LOS (≥6 days). Patients in this Group also had a higher chance of intraoperative blood loss, prolonged intubation, and required vasopressors postoperatively. There was also an increased odds of postoperative decline in renal function in the obese population. Patients with prior history of CAD, hypertension, diabetes mellitus, and urgent or emergent procedures were found to be risk factors for LOS>6 days in obese patients. An increase in the surgeons' case volume was associated with lesser odds of operative time ≥ 250 mins; however, no significant impact was found on postoperative LOS. Hospitals where ≥ 25% ABF bypasses were performed on obese patients were also more likely to have LOS <6 days after ABF operations, compared to hospitals where <25% of ABF bypasses were performed on obese patients. Patients undergoing ABF for CLTI or acute limb ischemia had longer LOS and increased operative time.

CONCLUSION

ABF bypass in obese patients is associated with prolonged operative times and longer LOS than in non-obese patients. Obese patients operated by surgeons with more cases of ABF bypasses have shorter operative times. An increasing hospital's obese patient proportion was related to decreased LOS. These findings support the known volume-outcome relationship that with a higher surgeon case volume and increased proportion of obese patients in a hospital, there is an improvement in outcomes of obese patients undergoing ABF bypass.

Inverse relation of body weight with short-term and long-term mortality following hip fracture surgery: a meta-analysis

Background

The obesity paradox, which suggests that high body weight is positively associated with survival in some diseases, has not been proven in patients with hip fracture. In this study, meta-analysis of previous studies on the impacts of body weight on postoperative mortality following hip fracture surgery in older adults was conducted.

Methods

PubMed, Embase, and Cochrane library were searched for studies investigating the correlation between mortality after hip fracture surgery and body weight. The search main items included: (“Body mass index” OR “BMI” or “body weight”) and (“hip fracture” or “hip fractures”). Studies contained data on short-term (≤ 30-day) and long-term (≥ 1 year) mortality after hip fracture and its association with distinct body weight or BMI groups were reported as full-text articles were included in this meta-analysis.

Results

Eleven separate studies were included. The definitions of underweight and obesity differed among the included studies, but the majority of the enrolled studies used the average body weight definition of a BMI of 18.5 to 24.9 kg/m²; underweight referred to a BMI of < 18.5 kg/m²; and obesity pertained to a BMI of > 30 kg/m². Based on the generalized definitions of body-weight groups from the enrolled studies, the group with obesity had lower long-term (odds ratio [OR]: 0.63, 95% CI: 0.50–0.79, P < 0.00001) and short-term (OR: 0.63, 95% CI: 0.58–0.68, P ≤ 0.00001) mortality rates after hip fracture surgery when compared with patients with average-weight group. However, compared with the average-weight group, the underweight group had higher long-term (OR: 1.51, 95% CI: 1.15-1.98, P=0.003) and short-term (OR: 1.49, 95% CI: 1.29-1.72, P<0.00001) mortality rates after hip fracture surgery.

Conclusions

Current evidence demonstrates an inverse relation of body weight with long-term and short-term mortality after hip fracture surgery in older adults.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03131-3.

Outcomes following Revision Total Knee Arthroplasty Septic versus Aseptic Failure: A National Propensity-Score-Matched Comparison

Although periprosthetic joint infection (PJI) has been hypothesized to increase the risk of complications following revision total knee arthroplasty (TKA), strong evidence linking the two is lacking. The aim of this study was to determine whether PJI is an independent risk factor for inpatient perioperative complications, and increased resource use in patients undergoing revision TKA. We relied on the US Nationwide Inpatient Sample (NIS) to identify patients with PJI or non-PJI treated with revision TKA between 2002 and 2014. Overall, 5,316 (16.4%) and 27,033 (83.6%) patients were categorized as PJI and non-PJI, respectively. To adjust for potential baseline differences between the two groups, propensity-score-based matching was performed. This resulted in 5,187 (50%) PJI patients matched to 5,187 (50%) non-PJI patients. The rates of postoperative complications, blood transfusions, prolonged length of stay (pLOS), in-hospital cost, and in-hospital mortality were assessed for both groups. Multivariable logistic regression analyses were performed within the cohort after propensity-score matching. For PJI versus non-PJI, respectively, the following rates were recorded: blood transfusions, 28.3 versus 18.4% (p < 0.0001); postoperative complications, 27.5 versus 19.8% (p < 0.0001); pLOS (>4 d), 61.9 versus 26.9% (p < 0.0001); in-hospital cost (>$39,929), 55.8 versus 44.2% (p < 0.0001); in-hospital mortality, 0.6 versus 0.3% (p = 0.016). In multivariable logistic regression analyses, PJI patients were more likely to receive a blood transfusion (odds ratio [OR]: 1.78; p < 0.0001), to experience postoperative complications (OR: 1.56; p < 0.0001), to have a higher in-hospital cost (OR: 1.65; p < 0.0001), to have a pLOS following surgery following surgery (OR: 4.69; p < 0.0001), and to have a higher in-hospital mortality (OR: 2.14; p = 0.019). After adjustment for potential selection biases, PJI is associated with more adverse perioperative outcomes and resource use than non-PJI patients. This is a Level II (level of evidence), prognostic study.

Complications and 30-Day Mortality Rate After Hip Fracture Surgery in Superobese Patients

OBJECTIVE

Paradoxically, overweight and obesity are associated with lower odds of complications and death after hip fracture surgery. Our objective was to determine whether this "obesity paradox" extends to patients with "superobesity." In this study, we compared rates of complications and death among superobese patients with those of patients in other body mass index (BMI) categories.

METHODS

Using the National Surgical Quality Improvement Program database, we identified >100,000 hip fracture surgeries performed from 2012 to 2018. Patients were categorized as underweight (BMI <18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25-29.9), obese (BMI 30-39.9), morbidly obese (BMI 40-49.9), or superobese (BMI ≥50). We analyzed patient characteristics, surgical characteristics, and 30-day outcomes. Using multivariate regression with normal-weight patients as the referent, we determined odds of major complications, minor complications, and death within 30 days by BMI category.

RESULTS

Of 440 superobese patients, 20% had major complications, 33% had minor complications, and 5.2% died within 30 days after surgery. When comparing patients in other BMI categories with normal-weight patients, superobese patients had the highest odds of major complications [odds ratio (OR): 1.6, 95% confidence interval (CI), 1.2-2.0] but did not have significantly different odds of death (OR: 0.91, 95% CI, 0.59-1.4) or minor complications (OR: 1.2, 95% CI, 0.94-1.4).

CONCLUSION

Superobese patients had significantly higher odds of major complications within 30 days after hip fracture surgery compared with all other patients. This "obesity paradox" did not apply to superobese patients.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a Complete Description of Levels of Evidence.

Mortality After Elective Surgery: The Potential Role for Preoperative Palliative Care

BACKGROUND

Preoperative optimization is increasingly emphasized for high-risk surgical patients. One critical component of this includes preoperative advanced care planning to promote goal-concordant care. We aimed to define a subset of patients that might benefit from preoperative palliative care consult for advanced care planning.

MATERIALS AND METHODS

We examined adult patients admitted from January 2016 to December 2018 to a university health system for elective surgery. Multivariate logistic regression was used to identify variables associated with death within 1 y, and presence of palliative care consults preoperatively. Chi-square analysis evaluated the impact of a palliative care consult on advanced care planning variables.

RESULTS

Of the 29,132 inpatient elective procedures performed, there was a 2.0% mortality rate at 6 mo and 3.5% at 1 y. Those who died were more likely to be older, male, underweight (BMI <18), or have undergone an otolaryngology, neurosurgery or thoracic procedure type (all P-values < 0.05). At the time of admission, 29% had an advance directive, 90% had a documented code status, and 0.3% had a preoperative palliative care consult. Patients were more likely to have an advanced directive, a power of attorney, a documented code status, and have a do not resuscitate order if they had a palliative care consult (all P-values <0.05). The mortality rates and preoperative palliative care rates per procedure type did not follow similar trends.

CONCLUSIONS

Preoperative palliative care consultation before elective admissions for surgery had a significant impact on advanced care planning.

Perioperative Heart-Brain Axis Protection in Obese Surgical Patients: The Nutrigenomic Approach

The number of obese patients undergoing cardiac and noncardiac surgery is rapidly increasing because they are more prone to concomitant diseases, such as diabetes, thrombosis, sleep-disordered breathing, cardiovascular and cerebrovascular disorders. Even if guidelines are already available to manage anesthesia and surgery of obese patients, the assessment of the perioperative morbidity and mortality from heart and brain disorders in morbidly obese surgical patients will be challenging in the next years. The present review will recapitulate the new mechanisms underlying the Heart-brain Axis (HBA) vulnerability during the perioperative period in healthy and morbidly obese patients. Finally, we will describe the nutrigenomics approach, an emerging noninvasive dietary tool, to maintain a healthy body weight and to minimize the HBA propensity to injury in obese individuals undergoing all types of surgery by personalized intake of plant compounds that may regulate the switch from health to disease in an epigenetic manner. Our review provides current insights into the mechanisms underlying HBA response in obese surgical patients and how they are modulated by epigenetically active food constituents.

Surgical site infection in overweight and obese Total Knee Arthroplasty patients

Purpose

This aim of this study was to evaluate the rate of surgical site infection (SSI) in patients undergoing Total Knee Arthroplasty (TKA), to improve our understanding of the associations between infection rate and obesity.

Methods

Data was reviewed for 839 primary TKA procedures performed at a National Arthroplasty Centre over one year (April 2007-March 2008). SSI data was collected at 30 days and one year post-operatively. Patients were grouped guided by the WHO classifications of obesity; normal (BMI < 25.0), overweight (BMI 25.00-29.99), obese class I (BMI 30.00-34.99), obese class II (BMI 35.00-39.99), obese class III (BMI ≥ 40.00). Statistical significance was assessed by Fisher's Exact Test.

Results

When grouped by BMI, 30.9% of patients were obese class I, 19.0% obese class II and 8.7% obese class III. Of the total cohort, 22 patients (2.6%) had superficial SSI and 13 (1.5%) had deep SSI. When comparing the obese class III cohort to all other cohorts (non-obese class III), the odds ratios for superficial SSI was 4.20 (95% CI [1.59, 11.09]; p = 0.009) and deep SSI was 6.97 (95% CI [2.22, 21.89]; p = 0.003). In the obese class III cohort, superficial SSI rate was higher in females (8.9%) than males (5.9%), yet deep SSI demonstrated the opposite, with a higher occurrence in males (11.8%) compared to females (5.4%).

Conclusion

This study suggests that obese class III TKA patients are at increased odds of superficial and deep SSI compared to other BMI cohorts. Interestingly, male obese class III patients demonstrated a higher rate of deep infection compared to their female counterparts. However, it must be noted that study findings are limited as confounders were unable to be accounted for in this retrospective study design.

Obese Patients Undergoing Ileal Pouch-Anal Anastomosis: Short-and Long-term Surgical Outcomes

BACKGROUND

Ileal pouch-anal anastomosis (IPAA) is the preferred surgical treatment for patients with chronic ulcerative colitis. Little is known about the impact of obesity on operative characteristics, short-term postoperative complications and long-term functional outcomes after IPAA.

METHODS

A retrospective review of all patients undergoing IPAA for chronic ulcerative colitis at a single tertiary referral center between January 2002 and August 2013 was performed. Thirty-day postoperative complications and long-term functional outcomes were analyzed according to body mass index.

RESULTS

Nine hundred nine IPAAs (154 obese [body mass index ≥ 30] and 755 not obese [body mass index < 30]) were performed during the study period. For 2-stage IPAA, obese patients were less likely to undergo laparoscopic IPAA (P < 0.0001), had greater estimated blood loss (P = 0.005), and longer operative times (P = 0.02). For 3-stage IPAA, obese patients were less likely to undergo a laparoscopic procedure (P = 0.03), had greater estimated blood loss (P < 0.0001), and longer operative times (P = 0.0002). Postoperatively, obese patients had a longer length of stay after a 2-stage procedure (P = 0.009), an increased rate of superficial surgical site infections (P = 0.003), and an increased rate of urinary tract infections (P = 0.03). Of the 61% (n = 546) of patients with IPAA with long-term (median 5.0 years) follow-up, there were no significant differences in functional outcomes including incontinence, frequency of bowel movements, pad usage, and pouchitis between the groups.

CONCLUSIONS

Obesity impacts intraoperative complexity and 30-day postoperative outcomes. Long-term functional outcomes are not affected. These findings underscore the need to counsel patients on preoperative weight loss before undergoing elective IPAA.

Obesity Does Not Impact Perioperative or Postoperative Outcomes in Patients with Inflammatory Bowel Disease

BACKGROUND

While the prevalence of obesity in IBD patients is rapidly increasing, it is unclear if obesity impacts surgical outcomes in this population. We aim to investigate the effects of BMI on perioperative and postoperative outcomes in IBD patients by stratifying patients into BMI groups and comparing outcomes between these groups.

METHODS

This is a retrospective cohort study where IBD patients who underwent intestinal surgeries between the years of 2000 to 2014 were identified. The patients were divided into groups based on BMI: underweight (BMI <18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25-29.9), and obese (BMI ≥30). Preoperative patient demographics, operative variables, and postoperative complications were collected and compared between BMI groups.

RESULTS

A total of 391 surgeries were reviewed (34 underweight, 187 normal weight, 105 overweight, and 65 obese) from 325 patients. No differences were observed in preoperative patient demographics, type of IBD, preoperative steroid or biologic mediator use, or mean laboratory values. No differences were observed in percent operative procedures with anastomosis, surgeries converted to open, estimated blood loss, intraoperative complications, and median operative time. Thirty-day postoperative complication rates including total complications, wound infection, or anastomotic leak were similar between groups. There was a statistically significant increased postoperative bleeding risk (p = 0.029) in underweight patients. The relative percent for increased postoperative bleeding risk between BMI groups was as follows: 2.9% in underweight, zero in normal weight, 2.9% in overweight, and zero in obese.

CONCLUSION

Obesity does not appear to impact intraoperative variables nor does obesity appear to worsen postoperative complication rates in IBD patients.

Development and validation of the Surgical Outcome Risk Tool (SORT)

Background

Existing risk stratification tools have limitations and clinical experience suggests they are not used routinely. The aim of this study was to develop and validate a preoperative risk stratification tool to predict 30-day mortality after non-cardiac surgery in adults by analysis of data from the observational National Confidential Enquiry into Patient Outcome and Death (NCEPOD) Knowing the Risk study.

Methods

The data set was split into derivation and validation cohorts. Logistic regression was used to construct a model in the derivation cohort to create the Surgical Outcome Risk Tool (SORT), which was tested in the validation cohort.

Results

Prospective data for 19 097 cases in 326 hospitals were obtained from the NCEPOD study. Following exclusion of 2309, details of 16 788 patients were analysed (derivation cohort 11 219, validation cohort 5569). A model of 45 risk factors was refined on repeated regression analyses to develop a model comprising six variables: American Society of Anesthesiologists Physical Status (ASA-PS) grade, urgency of surgery (expedited, urgent, immediate), high-risk surgical specialty (gastrointestinal, thoracic, vascular), surgical severity (from minor to complex major), cancer and age 65 years or over. In the validation cohort, the SORT was well calibrated and demonstrated better discrimination than the ASA-PS and Surgical Risk Scale; areas under the receiver operating characteristic (ROC) curve were 0·91 (95 per cent c.i. 0·88 to 0·94), 0·87 (0·84 to 0·91) and 0·88 (0·84 to 0·92) respectively (P < 0·001).

Conclusion

The SORT allows rapid and simple data entry of six preoperative variables, and provides a percentage mortality risk for individuals undergoing surgery.

Early Detection of Coagulation Abnormalities in Patients at Nutritional Risk: The Novel Role of Thromboelastography

It is believed that malnutrition is common among hospitalized patients and associated with increased risk of morbidity and mortality. It is unclear if it is more likely to cause coagulation disorders in patients with malnutrition. We, therefore, investigate the feasibility of using thromboelastography (TEG) in early detection of coagulation abnormalities in patients at nutritional risk. Fifty successive adult patients with gastrointestinal disease were prospectively divided into one of two groups according to nutritional risk score (less than 3 and 3 or greater). Blood samples were collected at admission for analysis of standard biochemical parameters, routine coagulation tests, and TEG parameters. A total of 62 per cent of patients (n = 31) were at nutritional risk. Serum concentrations of prealbumin, transferrin, total protein, low-density lipoprotein, high-density lipoprotein, and cholesterol were much lower in the nutritional risk group than in the no-risk group ( P ≤ 0.05). There was no significant difference in routine coagulation tests, whereas most of the TEG parameters showed significant differences between the two groups. The overall coagulation function was worse in patients at nutritional risk than in patients with good nutritional status ( P ≤ 0.01). TEG appears to be more sensitive for the detection of coagulation abnormalities compared with routine coagulation tests in patients at nutritional risk. The phenomenon described in this article should be useful in further studies of patients with malnutrition.

Computed tomography attenuation and patient characteristics as predictors of complications after pancreaticoduodenectomy

OBJECTIVES

Morbidity after pancreaticoduodenectomy (PD) remains high. Computed tomography (CT) of intra-abdominal tissue has not been thoroughly evaluated to establish associations with the occurrence of complications after PD. The current study sought to determine whether differences in non-enhanced visceral attenuation predicted complications after PD.

METHODS

Outcomes in patients undergoing PD were analysed according to the Clavien system for classifying complications and the International Study Group on Pancreatic Fistula system for classifying postoperative pancreatic fistula (POPF). Preoperative non-enhanced CT scans were evaluated by a blinded investigator for attenuation of abdominal viscera and fat thickness. Data on pancreatic firmness and pancreatic duct size were collected. Univariate and multivariate analyses were performed.

RESULTS

A total of 134 patients underwent PD for malignant and benign disease. Rates of morbidity, mortality and POPF at 90 days were 61%, 4% and 23%, respectively. Patients with a body mass index of > 25 kg/m(2) had higher rates of POPF (P = 0.05) and complications (P < 0.01). In multivariate analysis, patients were more likely to develop any complication as CT attenuation decreased for paraspinus muscle (P < 0.01), spleen (P < 0.03) and liver (P = 0.01) parenchyma.

CONCLUSIONS

Postoperative complications after PD remain prevalent. Decreased CT attenuation of abdominal viscera is an independent predictor of morbidity after PD and suggests a high-risk patient physiology for pancreatic resection.