The Obesity Paradox in the Trauma Patient: Normal May not Be Better

An evaluation of the "Obesity Paradox" in isolated blunt abdominal trauma in the United States

BACKGROUND

The obesity paradox theorizes a survival benefit in trauma patients secondary to the cushioning effect of adiposity. We aim to evaluate the impact of body mass index (BMI) on abdominal injury severity, morbidity, and mortality in adults with isolated, blunt abdominal trauma in the United States.

METHODS

We reviewed the National Trauma Data Bank (2013-2021) for adults sustaining isolated, blunt abdominal trauma stratified by BMI. We performed a doubly robust, augmented inverse-propensity weighted multivariable logistic regression to estimate the average treatment effect (ATE) of BMI on mortality and the presence of abdominal organ injury.

RESULTS

36,350 patients met the inclusion criteria. In our study, 41.4 % of patients were normal-weight (BMI 18.5-24.9), 20.6 % were obese (BMI 30-39.9), and 4.7 % were severely obese (BMI≥40). In these cohorts, the abdominal abbreviated injury scale (AIS) was 2 (2 -3). Obese and severely obese patients had significantly reduced presence of pancreas, spleen, liver, kidney, and small bowel injuries. The predicted probability of abdominal AIS severity decreased significantly with increasing BMI. Crude mortality was significantly higher in obese (1.3 %) and severely obese patients (1.3 %) compared to normal-weight patients (0.7 %). Obese and severely obese patients demonstrated non-statistically significant changes in the mortality of +26.4 % (ATE 0.264, 95 %CI -0.108-0.637, p = 0.164) and +55.5 % (ATE 0.555, 95 %CI -0.284-1.394, p = 0.195) respectively, compared to normal weight patients.

CONCLUSION

BMI may protect against abdominal injury in adults with isolated, blunt abdominal trauma. Mortality did not decrease in association with increasing BMI, as this may be offset by the increase in co-morbidities in this population.

The association between body mass index and physical function in adult burn survivors: A Burn Model System National Database study

INTRODUCTION

An area of rehabilitation research in burns is the impact of co-morbidities on disease trajectory. Obesity is a comorbidity of increasing public health concern, but its role remains controversial regarding burn injury and physical recovery. Our aim was to evaluate the association between body mass index (BMI) categories as a measure of obesity at discharge and self-reported physical function (PF) during recovery of adult burn survivors.

METHODS

This is a retrospective study on data collected by four major US burn centers, which contribute to the Burn Model System National Database. The data included BMI obtained at hospital discharge and self-reported PF-mobility, using the PROMIS measures assessed at 6, 12, and 24 months after burn. Subjects were classified into weight status categories based on BMI: underweight (BMI <18.5), normal weight (18.5 ≤ BMI <25), overweight (25 ≤ BMI <30), obesity class 1 (30 ≤ BMI <35), obesity class 2 (35 ≤ BMI <40), and obesity class 3 (BMI ≥40). Mixed-effects linear regression models were used to assess the association between BMI categories and PF scores over time, adjusted for patient and injury characteristics.

RESULTS

A total of 496 adult burn patients aged 47 ± 16 years were included, with mean total body surface area (TBSA) burned of 18 ± 19 % and mean BMI at discharge of 28 ± 7 kg/m2. PROMIS PF scores significantly improved over time in the recovery phase after burn (time effect, p < 0.001). Compared to overweight burn patients, normal-underweights exhibited lower PF score by an average of 4.06 units (p = 0.001) but scores increased linearly by an estimated 0.17 units per month (p = 0.01) over the 24 months after discharge. Similarly, compared to overweight burn patients, class 1 obese reported lower PF score by a mean 2.67 units (p = 0.07) but PF increased linearly by 0.15 units per month (p = 0.07) over the 24 months after discharge. These findings were independent of the effects of age at discharge, sex, TBSA burned, and hand and leg burn.

CONCLUSION

Being overweight was associated with improved and faster recovery of PF scores compared to normal, underweight, and obese burn patients during long-term recovery. Hence, our data suggests that long-term recovery and restoration of PF in adult burn survivors is not compromised by a small excess in body weight.

Obesity and Penetrating Trauma: Outcomes from a Level 1 Trauma Center in New York City

Background

Obesity is associated with increased morbidity and mortality in trauma scenarios; however, there has been conflicting evidence on outcomes of obesity and penetrating injuries, specifically gunshot wounds and stab wounds. We hypothesized that obesity may be protective due to a "cushioning effect" attributed to increased adiposity.

Methods

This was a retrospective cohort study of patients presenting to a Level 1 Trauma Center with a penetrating trauma (gunshot/stab) injury during 2008-2021. Patients with a BMI ≥ 30 were compared to those with a BMI < 30. The primary outcome was Injury Severity Score (ISS). Secondary outcomes included intensive care unit (ICU) length of stay, days on ventilation, length of hospital stay, service of admission (trauma surgery, general surgery, discharged home, general medical floor), the body region of injury(s), Abbreviated Injury Scale (AIS), OR requirement, type of surgery, and discharge status. Statistical analysis was performed using χ2-test or Fisher's exact tests for categorical data, and Student's t-test or Mann-Whitney U-test for continuous variables with p < 0.05 as statistically significant. Subgroup analysis was performed based on the mechanism of injury.

Results

There were 721 patients that met inclusion criteria, of which 540 were classified in the non-obese group and 181 (25.1%) in the obese group. The primary outcome, mean ISS score, in obese patients (9.0, SD = 13.0) and non-obese patients (9.4, SD = 13.8) was similar between groups respectively. Secondary outcomes, which included rates of severe abdominal injury (AIS ≥ 3), rates of intra-abdominal organ injury, and rates of gastro-intestinal resection, were also similar between non-obese and obese patients.

Conclusion

This study did not demonstrate the existence of a "cushioning effect" in the setting of penetrating traumatic injury. Patients with increased BMI had similar a ISS score and patterns of injury as their non-obese counterparts.

The Obesity Paradox in the Pediatric Trauma Patient

BACKGROUND

Obesity is a chronic disease that adversely impacts patient outcomes and increasingly affecting the pediatric population. According to the CDC, in 2020 the prevalence of obesity among children and adolescents was estimated to be as high as 19.7%. The obesity paradox is the increased survival for overweight and obese adult trauma patients when compared to patients with healthy weights. The aim of this study was to analyze the impact of BMI and outcomes in the pediatric trauma population.

METHODS

Trauma patients in the 2-18 years age group and reported to the 2017-2019 National Trauma Data Bank were identified. CDC growth charts and z-scores were calculated to categorize patients into four subgroups: underweight (<5th percentile), healthy weight (5th-85th percentile), overweight (85th-95th percentile), and obesity (>95th percentile). Primary outcome studied was the mortality rate. Secondary outcomes included injury severity score (ISS), hospital length of stay (LOS), ICU LOS, and number of days on a ventilator. Continuous and categorical data were analyzed using ANOVA and Chi-squared test, respectively, using the healthy BMI category as reference group. P < 0.05 was considered significant.

RESULTS

A total of 161,458 patients [Underweight: 9148 (6%), Healthy weight: 88,009 (55%), Overweight: 26,740 (17%), and Obese: 37,561 (23%)] were included. The mean age was 11 years (SD:5.1). Total mortality for the patient set was 1825 (1.13%). The lowest mortality rate was in the obese group. The ISS was lowest in the obese group, while ICU LOS and days on ventilator were no different than control patients. Hospital LOS and transfer to rehabilitation rates were higher in the obese population.

CONCLUSION

Obesity appears to have a protective effect on mortality and significantly better secondary outcomes in the pediatric trauma population. Further study is necessary to evaluate the interplay between body weight and outcomes in pediatric trauma and disease states.

LEVEL OF EVIDENCE

III.

Adverse Events Associated With Disparity Between Patients' BMI and Operating Table Size-A Need for Improved Surgical Innovations

BACKGROUND

The lack of proper equipment to accommodate patients with high BMI can jeopardize the safety of the patients and medical staff. In this review, we aim to discuss the availability of obesity accommodations in the operating room, along with its impact, implications, and future recommendations.

METHODS

Four databases were searched for articles pertaining to surgical table dimensions and the implications for safety, with a special focus on patients with larger BMIs. Articles were separated into 4 categories: Existing OR Table Options, Safety Implications for Patients, Reported Adverse Events Associated with Operating Table Inadequacy, and Safety Implications for Medical Staff.

RESULTS

A total of 18 articles and documents were included in this review. Most of the literature that discusses surgical tables with higher weight capacity is specific only to weight loss surgeries. Operating table dimensions have changed little in the past 100 years and standard operating tables have weight limits of 500 pounds. Several case reports underline the hazards of inadequately sized surgical tables.

CONCLUSIONS

This review demonstrates that a lack of proper equipment, such as surgical tables with adequate width and weight limits, can be a major contributor to the endangerment of bariatric surgical patients and the medical professionals who care for them. Further research and surgical innovation may be required to develop superior operating tables to address the unique concerns of this patient populations.

The association of radiologic body composition parameters with clinical outcomes in level-1 trauma patients

PURPOSE

The present study aims to assess whether CT-derived muscle mass, muscle density, and visceral fat mass are associated with in-hospital complications and clinical outcome in level-1 trauma patients.

METHODS

A retrospective cohort study was conducted on adult patients admitted to the University Medical Center Utrecht following a trauma between January 1 and December 31, 2017. Trauma patients aged 16 years or older without severe neurological injuries, who underwent a CT that included the abdomen within 7 days of admission, were included. An artificial intelligence (AI) algorithm was used to retrieve muscle areas to calculate the psoas muscle index and to retrieve psoas muscle radiation attenuation and visceral fat (VF) area from axial CT images. Multivariable logistic and linear regression analyses were performed to assess associations between body composition parameters and outcomes.

RESULTS

A total of 404 patients were included for analysis. The median age was 49 years (interquartile range [IQR] 30-64), and 66.6% were male. Severe comorbidities (ASA 3-4) were seen in 10.9%, and the median ISS was 9 (IQR 5-14). Psoas muscle index was not independently associated with complications, but it was associated with ICU admission (odds ratio [OR] 0.79, 95% confidence interval [CI] 0.65-0.95), and an unfavorable Glasgow Outcome Scale (GOS) score at discharge (OR 0.62, 95% CI 0.45-0.85). Psoas muscle radiation attenuation was independently associated with the development of any complication (OR 0.60, 95% CI 0.42-0.85), pneumonia (OR 0.63, 95% CI 0.41-0.96), and delirium (OR 0.49, 95% CI 0.28-0.87). VF was associated with developing a delirium (OR 1.95, 95% CI 1.12-3.41).

CONCLUSION

In level-1 trauma patients without severe neurological injuries, automatically derived body composition parameters are able to independently predict an increased risk of specific complications and other poor outcomes.

Obese adolescents have higher risk for severe lower extremity fractures after falling

INTRODUCTION

Reports vary on the impact of obesity on the incidence of lower extremity fractures after a fall. We hypothesized that obese adolescents (OA) presenting after a fall have a higher risk of any and severe lower extremity fractures compared to non-OAs.

METHODS

A national database was queried for adolescents (12-17 years old) after a fall. Primary outcome included lower extremity fracture. Adolescents with a body mass index (BMI) ≥ 30 (OA) were compared to adolescents with a BMI < 30 (non-OA).

RESULTS

From 20,264 falls, 2523 (12.5%) included OAs. Compared to non-OAs, the rate of any lower extremity fracture was higher for OAs (51.5% vs. 30.7%, p < 0.001). This remained true for lower extremity fractures at all locations (all p < 0.05). After adjusting for sex and age, associated risk for any lower extremity fracture (OR 2.41, CI 2.22-2.63, p < 0.001) and severe lower extremity fracture (OR 1.31, CI 1.15-1.49, p < 0.001) was higher for OAs. This remained true in subset analyses of ground level falls (GLF) and falls from height (FFH) (all p < 0.05).

CONCLUSIONS

Obesity significantly impacts adolescents' risk of all types of lower extremity fractures after FFH or GLF. Hence, providers should have heightened awareness for possible lower extremity fractures in OAs.

LEVEL OF EVIDENCE

IV.

Injury characteristics and predictors of mortality in patients undergoing pancreatic excision after abdominal trauma: A National Trauma Data Bank (NTDB) study

Pancreatic tumors and pancreatitis are the main indications for pancreatic excision (PE). However, little is known about this type of intervention in the context of traumatic injuries. Surgical care for traumatic pancreatic injuries is challenging because of the location of the organ and the lack of information on trauma mechanisms, vital signs, hospital deposition characteristics, and associated injuries. This study examined the demographics, vital signs, associated injuries, clinical outcomes, and predictors of in-hospital mortality in patients with abdominal trauma who had undergone PE. Following the Strengthening the Reporting of Observational Studies in Epidemiology guidelines, we analyzed the National Trauma Data Bank and identified patients who underwent PE for penetrating or blunt trauma after an abdominal injury. Patients with significant injuries in other regions (abbreviated injury scale score ≥ 2) were excluded. Of the 403 patients who underwent PE, 232 had penetrating trauma (PT), and 171 had blunt trauma (BT). The concomitant splenic injury was more prevalent in the BT group; however, the frequency of splenectomy was comparable between groups. In particular, concomitant kidney, small intestine, stomach, colon, and liver injuries were more common in the PT group (all P < .05). Most injuries were observed in the pancreatic body and tail regions. The trauma mechanisms also differed between the groups, with motor vehicles accounting for most of the injuries in the BT group and gunshots accounting for most of the injuries in the PT group. In the PT group, major liver lacerations were approximately 3 times more common (P < .001). The in-hospital mortality rate was 12.4%, with no major differences between the PT and BT groups. Furthermore, there was no difference between BT and PT with respect to the location of the injuries in the pancreas, with the pancreatic tail and body accounting for almost 65% of injuries. Systolic blood pressure, Glasgow Coma Scale score, age, and major liver laceration were revealed by logistic regression as independent predictors of mortality, although trauma mechanisms and intent were not linked to mortality risk.

Does obesity predict morbidity and mortality amongst patients undergoing transfemoral amputations?

BACKGROUND

We investigated the role of obesity on morbidity and mortality in patients undergoing above knee amputation.

METHODS

Data of 4225 patients undergoing AKAs was extracted from NIS Database (2016-2019) for a retrospectively matched case-control study and were grouped into; Non-obese (N-Ob-BMI <29.9 kg/m²; n = 1413), class I/II obese (Ob-I/II-BMI: 30-39.9 kg/m²; n = 1413), and class III obese groups (Ob-IIIBMI > 40; n = 1399). Morbidity, mortality, length of stay, and hospital charges were analyzed.

RESULTS

Blood loss anemia (OR = 1.42; 95% CI = 1.19-1.64), superficial SSI (OR = 5.10; 95% CI = 1.4717.63) and acute kidney injury (AKI- OR = 1.42; 95% CI = 1.21-1.67) were higher in Ob-III patients. Mortality was 5.8%, 4.5%, and 6.4% in N-Ob, Ob-I/II and Ob-III patients (p < 0.001; Ob-I/II vs. Ob-III), respectively. Hospital LOS was 3 days higher in Ob-III (16.1 ± 18.0), comparatively resulting in $25,481 higher inpatient-hospital charge.

CONCLUSION

Patients in Ob-III group were noted to have increased morbidity, higher LOS, and inpatient-hospital cost.

Blood Count-Derived Inflammatory Markers Correlate with Lengthier Hospital Stay and Are Predictors of Pneumothorax Risk in Thoracic Trauma Patients

(1) Background: Trauma is one of the leading causes of death worldwide, with the chest being the third most frequent body part injured after abdominal and head trauma. Identifying and predicting injuries related to the trauma mechanism is the initial step in managing significant thoracic trauma. The purpose of this study is to assess the predictive capabilities of blood count-derived inflammatory markers at admission. (2) Materials and Methods: The current study was designed as an observational, analytical, retrospective cohort study. It included all patients over the age of 18 diagnosed with thoracic trauma, confirmed with a CT scan, and admitted to the Clinical Emergency Hospital of Targu Mureş, Romania. (3) Results: The occurrence of posttraumatic pneumothorax is highly linked to age (p = 0.002), tobacco use (p = 0.01), and obesity (p = 0.01). Furthermore, high values of all hematological ratios, such as the NLR, MLR, PLR, SII, SIRI, and AISI, are directly associated with the occurrence of pneumothorax (p < 0.001). Furthermore, increased values of the NLR, SII, SIRI, and AISI at admission predict a lengthier hospitalization (p = 0.003). (4) Conclusions: Increased neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), systemic inflammatory index (SII), aggregate inflammatory systemic index (AISI), and systemic inflammatory response index (SIRI) levels at admission highly predict the occurrence of pneumothorax, according to our data.

High Fat-to-Muscle Ratio Was Associated with Increased Clinical Severity in Patients with Abdominal Trauma

Overweight and moderate obesity confer a survival benefit in chronic diseases such as coronary artery disease and chronic kidney disease, which has been termed the "obesity paradox". However, whether this phenomenon exists in trauma patients remains controversial. We performed a retrospective cohort study in abdominal trauma patients admitted to a Level I trauma center in Nanjing, China between 2010 and 2020. In addition to the traditional body mass index (BMI) based measures, we further examined the association between body composition-based indices with clinical severity in trauma populations. Body composition indices including skeletal muscle index (SMI), fat tissue index (FTI), and total fat-to-muscle ratio (FTI/SMI) were measured using computed tomography. Our study found that overweight was associated with a four-fold risk of mortality (OR, 4.47 [95% CI, 1.40-14.97], p = 0.012) and obesity was associated with a seven-fold risk of mortality (OR, 6.56 [95% CI, 1.07-36.57], p = 0.032) compared to normal weight. Patients with high FTI/SMI had a three-fold risk of mortality (OR, 3.06 [95% CI, 1.08-10.16], p = 0.046) and double the risk of an intensive care unit length of stay ≥ 5 d (OR, 1.75 [95% CI, 1.06-2.91], p = 0.031) compared to patients with low FTI/SMI. The obesity paradox was not observed in abdominal trauma patients, and high FTI/SMI ratio was independently associated with increased clinical severity.

INFLUENCE OF OBESITY ON VASCULAR DYSFUNCTION AFTER TRAUMATIC HEMORRHAGE

ABSTRACT

Background: Obesity increases the risk for morbidity and mortality after trauma. These complications are associated with profound vascular damage. Traumatic hemorrhage acutely attenuates vascular responsiveness, but the impact of obesity on this dysfunction is not known. The local inflammatory response in vascular cells is also unknown. We hypothesized that obesity potentiates trauma-induced vascular inflammation and dysfunction. Methods: Male Sprague-Dawley rats (~250 g) were fed normal chow (NC; 13.5% kcal fat, n = 20) or high-fat (HF; 60% kcal fat, n = 20) diets for 6 to 8 weeks. Under anesthesia, hemorrhage was induced by a mesenteric artery laceration, a Grade V splenic injury, and hypotension (MAP = 30-40 mm Hg) for 30 minutes. Vascular responsiveness was assessed ex vivo in isolated mesenteric arteries prehemorrhage and posthemorrhage. Gene expression for IL-1β, and IL-6, prooxidant nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2), and α-adrenergic receptor were assessed in carotid artery endothelial cells (ECs) and non-ECs (media + adventitia). Results: In NC rats, hemorrhage attenuated norepinephrine-induced vasoconstriction and endothelium-dependent vasodilation to acetylcholine. In HF rats, baseline norepinephrine-induced vasoconstriction was attenuated compared with NC, but vasoconstriction and endothelium-dependent vasodilation did not change prehemorrhage to posthemorrhage. Hemorrhage led to elevated IL-1β gene expression in ECs and elevated IL1β, IL-6, NOX2, and α-adrenergic receptor gene expression in the media + adventitia compared with sham. HF rats had greater EC IL-1 β and NOX2 gene expression compared with NC rats. The hemorrhage-induced elevation of IL-1β in the media + adventitia was greatest in HF rats. Conclusion: Traumatic hemorrhage attenuates vascular responsiveness and induces vascular inflammation. The attenuated vascular responsiveness after hemorrhage is absent in obese rats, while the elevated vascular inflammation persists. A HF diet amplifies the arterial inflammation after hemorrhage. Altered vascular responsiveness and vascular inflammation may contribute to worse outcomes in obese trauma patients.

Obesity and outcomes in trauma - a systematic review and meta-analysis

BACKGROUND

The physiological abnormalities relating to obesity and metabolic syndrome can contribute to worse outcomes following trauma especially in class 2 and 3 obesity. The aim of this systematic review was to determine whether patients with a higher class of obesity who suffer traumatic injury have a higher risk of worse outcomes including in-hospital mortality than normal-weight patients.

METHODS

A systematic search of MEDLINE, EMBASE, CENTRAL, Web of Science and CINAHL was performed for studies that reported a comparison of in-hospital obesity-related outcomes against normal-weight individuals aged 15 years and older following trauma. Single or multiple injuries from either blunt and/or penetrating trauma were included. Burn-related injuries, isolated head injury and studies focusing on orthopaedic related perioperative complications were excluded.

RESULTS

The search yielded 7405 articles; 26 were included in this systematic review. 945,511 patients had a BMI>30. A random-effects meta-analysis was performed for analysis of all four outcomes. Patients with class 3 obesity (BMI>40) have significantly higher odds of in-hospital mortality than normal-BMI individuals following blunt and penetrating trauma (OR, 1.75; 95% CI, 1.39-2.19, p=<0.00001), significantly longer hospital LOS (SMD, 0.23; 95% CI, 0.21-0.25; p<0.00001) and significantly longer ICU LOS (SMD, 0.19; 95% CI, 0.12-0.26; p<0.0001). In contrast, studies that examined blunt and penetrating trauma and classified obesity with a threshold of BMI>30 found no significant difference in the odds of in-hospital mortality (OR, 0.94; 95% CI, 0.86-1.02, p=0.13).

CONCLUSIONS

There is a higher risk of in-hospital mortality in patients living with class 3 obesity following trauma when compared with individuals with normal BMI. The management of patients with obesity is complex and trauma systems should develop specific weight related pathways to manage and anticipate the complications that arise in these patients. Systematic review registration number PROSPERO registration: CRD42021234482 Level of Evidence: Level 3.

Outcomes of the overweight and obese major trauma patient in the rural setting

PURPOSE

Overweight and obese patients are more prevalent in rural and remote areas and are of major public health concern in Australia. We aimed to evaluate the mortality and morbidity of overweight and obese trauma patients in the rural Australian context.

METHOD

This was a retrospective cohort study on 207 major trauma patients (injury severity score [ISS] > 12) treated at the Mackay Base Hospital between 2018 and 2021. Data was extracted from the Mackay Base Hospital trauma database and hospital records. Outcomes were compared between body mass index (BMI) groups.

RESULTS

There were 164 males (79%) and 43 females (21%). The average BMI was 27.09 (standard deviation 5.46). 7 patients (3%) were in the underweight category (BMI < 18.5 kg/m²), 70 (34%) were of normal weight (BMI 18.5-24.9 kg/m²), 79 (38%) were overweight (BMI 25-29.9 kg/m²), and 51 (25%) were obese (BMI > 30 kg/m²). The majority of trauma was blunt (n = 203, 98%). Compared to patients with normal BMI, obese patients were significantly more likely to require intubation, intensive care unit (ICU) admission, and have a longer ICU stay. There were no significant differences in requirement for surgery, duration of surgery, hospital length of stay, ventilator time, or mortality (P > 0.05). However, subgroup analysis of the obese patient group showed an increased rate of complications (sepsis, acute kidney injury, fluid overload and pneumonia), longer ventilation times, hospital and ICU length of stay with increasing BMI in these patients.

CONCLUSION

The majority of trauma presentations in our regional community are in overweight or obese patients. Overweight and obese patients are more likely to require intubation and have a longer intensive care unit admission than normal weight counterparts. Amongst obese patients, those with BMI > 40 (obesity class 3) are at significantly increased risk of complications.

Protective Role of Obesity on Trauma Impact: A Retrospective Analysis of Patients with Surgical Blunt Bowel Mesenteric Injury Due to Road Traffic Accidents

Background

The "cushion effect" theory proposes that increased body mass index (BMI) is associated with less severe abdomen injury following blunt abdomen trauma, while the "obesity paradox" describes the protective effect of obesity against mortality. However, most previous studies used the abdominal abbreviated injury scale as the outcomes seemed to be inadequate owing to the injuries to the abdominal organs, such as the spleen and liver, which may be attributable to the force that caused the chest trauma. This study aimed to use adult trauma patients with surgical blunt bowel mesenteric injuries (BBMIs) to investigate the influence of obesity on the clinical outcomes and overall morbidities.

Methods

This retrospective study reviewed the data of all hospitalized trauma patients between 2009 and 2019 and included all patients with surgically proven small bowel, colon, or mesenteric injuries due to a road traffic accident. Comparison of the outcomes was performed among 123 patients with surgically proven BBMI, who were categorized by BMI into the normal-weight (n = 73, BMI<25 kg/m²), overweight (n = 37, 25≤BMI≤30 kg/m²), and obese groups (n = 13, BMI>30 kg/m²).

Results

The obese group had a significantly lower incidence of isolated bowel injury (0%) compared with the normal-weight (35.6%) and overweight (16.2%) groups (p=0.005), but with higher incidence of isolated mesenteric injury or combined injury, although this was not significant. The obese group (92.3%) had a significantly higher percentage of overall morbidity than the normal-weight (61.6%) and overweight (70.3%) groups (p = 0.047). No significant difference was observed in the in-hospital mortality and 24-hour mortality among the three study groups.

Conclusion

The study findings do not support the existence of a cushion effect and obesity paradox of obesity in blunt abdominal trauma.

Adipose tissue: a neglected organ in the response to severe trauma?

Despite the manifold recent efforts to improve patient outcomes, trauma still is a clinical and socioeconomical issue of major relevance especially in younger people. The systemic immune reaction after severe injury is characterized by a strong pro- and anti-inflammatory response. Besides its functions as energy storage depot and organ-protective cushion, adipose tissue regulates vital processes via its secretion products. However, there is little awareness of the important role of adipose tissue in regulating the posttraumatic inflammatory response. In this review, we delineate the local and systemic role of adipose tissue in trauma and outline different aspects of adipose tissue as an immunologically active modifier of inflammation and as an immune target of injured remote organs after severe trauma.

The effect of obesity on inpatient outcomes in lower extremity trauma: A systematic review and meta-analysis

BACKGROUND

Obesity is a growing global health problem and a well-recognized risk factor for many medical conditions. This meta-analysis was conducted to assess the effect of obesity on overall complication occurrence, mortality, and hospital length of stay in patients with nonpathological lower limb trauma.

METHODS

The EMBASE, PUBMED, and MEDLINE electronic databases were searched from inception to April 1, 2020, for studies published in English. References cited by chosen studies were also checked manually for inclusion. Studies chosen for the analysis were prospective observational or retrospective cohort studies reporting on total complications of patients with acute traumatic, nonpathological, lower limb fractures that required internal fixation, with or without other underlying conditions. Two investigators independently reviewed the full text of eligible studies for inclusion and extracted data. Inconsistency was resolved through consultation with other authors.

RESULTS

Sixteen studies with 404,414 patients were investigated in this study. The data showed obesity was related with increased total complications (odds ratio [OR], 0.65; 95% confidence interval [CI], 0.51-0.83; p < 0.01), increased wound complications (OR, 0.41; 95% CI, 0.25-0.66; p < 0.01), and increased mortality rate (OR, 0.64; 95% CI, 0.45-0.91; p < 0.05). Six cohort studies also showed prolonged hospital length of stay in obese patients.

CONCLUSION

Our results suggest that obesity is associated with increased complication and mortality rates, as well as longer hospital length of stay in patients with lower-limb trauma who required surgical treatment. These findings may raise attention to optimize surgical technique and develop individualized treatment for obese patients.

LEVEL OF EVIDENCE

Systematic reviews, level IV.

Obesity and Anterior Abdominal Gunshot Wounds: A Cushion Effect

Background

Although the standard of care for anterior abdominal gunshot wounds (AAGSWs) is immediate laparotomy, these operations are associated with a high rate of negativity and potentially serious complications. Recent data suggest the possibility of selective non-operative management (SNOM) of AAGSWs, but none implicate body mass index (BMI) as a factor in patient selection. Anecdotal experience at our trauma center suggested a protective effect of obesity among patients with AAGSWs, and given the exceptionally high rate of obesity in the Bronx, we sought to analyze the associations of AAGSWs and BMI to inform future trauma research and management. In this study, we aimed to evaluate whether BMI is associated with injury severity, resource utilization, and clinical outcomes of AAGSWs.

Methodology

From our prospectively accrued trauma registry, we retrospectively abstracted all patients greater than 16 years old with Current Procedural Terminology codes associated with gunshot wounds from 2008 to 2016. The electronic medical record was reviewed to define a cohort of patients with at least one AAGSW. Patients were divided into the following cohorts based on BMI: underweight (UW, BMI: <18.5), normal weight (NW, BMI: 18.5-24.9), overweight (OW, BMI: 25-29.9), and obese (OB, BMI: ≥30). Among these cohorts, we analyzed data regarding injury severity, resource utilization, and clinical outcomes.

Results

In this study, none of the patients were UW, 17 (42.5%) patients were NW, 15 (37.5%) patients were OW, and eight (20%) patients were OB. One patient each in the NW and OB cohorts was successfully managed non-operatively, while all others underwent immediate exploratory laparotomy. The mean new injury severity score was significantly lower as BMI increased (NW = 30.9 ± 17.0, OW = 22.9 ± 16.1, and OB = 12.8 ± 13.7; p = 0.039). Patients in the OB cohort were less likely to have abdominal fascial penetration compared to the OW and NW cohorts (p = 0.027 and 0.004, respectively) and sustained fewer mean visceral injuries compared to the OW and NW cohorts (p = 0.027 and 0.045, respectively). OB patients were significantly more likely to have sustained two or more AAGSWs (OB = 27.5%, OW = 6.7%, and NW = 5.9%; p = 0.033), suggesting higher rates of tangential soft tissue injuries. The mean hospital length of stay down-trended as BMI increased but did not achieve statistical significance (NW = 7.4 ± 5.3, OW = 6.6 ± 6.7, and OB = 3.1 ± 2.3; p = 0.19). The OB cohort had the lowest mean hospital charges.

Conclusions

Obesity may yield a protective effect among AAGSW victims, and BMI may provide trauma surgeons another tool to triage patients for SNOM of AAGSWs, potentially diminishing the risks associated with negative laparotomy. Our data serve as the basis for the analysis of a larger patient cohort.

Emergencies in obese patients: a narrative review

Obesity is associated to an increased risk of morbidity and mortality due to respiratory, cardiovascular, metabolic, and neoplastic diseases. The aim of this narrative review is to assess the physio-pathological characteristics of obese patients and how they influence the clinical approach during different emergency settings, including cardiopulmonary resuscitation. A literature search for published manuscripts regarding emergency and obesity across MEDLINE, EMBASE, and Cochrane Central was performed including records till January 1, 2021. Increasing incidence of obesity causes growth in emergency maneuvers dealing with airway management, vascular accesses, and drug treatment due to both pharmacokinetic and pharmacodynamic alterations. Furthermore, instrumental diagnostics and in/out-hospital transport may represent further pitfalls. Therefore, people with severe obesity may be seriously disadvantaged in emergency health care settings, and this condition is enhanced during the COVID-19 pandemic, when obesity was stated as one of the most frequent comorbidity. Emergency in critical obese patients turns out to be an intellectual, procedural, and technical challenge. Organization and anticipation based on the understanding of the physiopathology related to obesity are very important for the physician to be mentally and physically ready to face the associated issues.

The Impact of Obesity on Renal Trauma Outcome: An Analysis of the National Trauma Data Bank from 2013 to 2016

BACKGROUND

The obesity paradox has been recently demonstrated in trauma patients, where improved survival was associated with overweight and obese patients compared to patients with normal weight, despite increased morbidity. Little is known whether this effect is mediated by lower injury severity. We aim to explore the association between body mass index (BMI) and renal trauma injury grade, morbidity, and in-hospital mortality.

METHODS

A retrospective cohort of adults with renal trauma was conducted using 2013-2016 National Trauma Data Bank. Multiple regression analyses were used to assess outcomes of interest across BMI categories with normal weight as reference, while adjusting for relevant covariates including kidney injury grade.

RESULTS

We analyzed 15181 renal injuries. Increasing BMI above normal progressively decreased the risk of high-grade renal trauma (HGRT). Subgroup analysis showed that this relationship was maintained in blunt injury, but there was no association in penetrating injury. Overweight (OR 1.02, CI 0.83-1.25, p = 0.841), class I (OR 0.92, CI 0.71-1.19, p = 0.524), and class II (OR 1.38, CI 0.99-1.91, p = 0.053) obesity were not protective against mortality, whereas class III obesity (OR 1.46, CI 1.03-2.06, p = 0.034) increased mortality odds. Increasing BMI by category was associated with a stepwise increase in odds of acute kidney injury, cardiovascular events, total hospital length of stay (LOS), intensive care unit LOS, and ventilator days.

CONCLUSIONS

Increasing BMI was associated with decreased risk of HGRT in blunt trauma. Overweight and obesity were associated with increased morbidity but not with a protective effect on mortality. The obesity paradox does not exist in kidney trauma when injury grade is accounted for.

Low body mass index is associated with increased mortality in patients with pelvic and acetabular fractures

AIMS

Fractures of the pelvis and acetabulum are often the consequence of high energy trauma in young individuals or fragility fractures in osteoporotic bone. They can be life-threatening or life changing injuries. No published data exists comparing body mass index (BMI) and mortality for this patient group. The aim of this study was to identify if low BMI (<18.5) was a predictor of morbidity and mortality for patients with these injuries.

PATIENTS AND METHODS

Of the 1033 patients with pelvic or acetabular fractures referred to a single level 1 major trauma centre (MTC) over a 4.5-year period (August 2015 - January 2020); we retrospectively analysed data for all admitted patients. Data was collected on demographics, injury pattern, operative intervention and complications. Comparison was made between patients that were underweight (BMI<18.5) and patients that were not. Both in-hospital and post discharge complications were recorded including pulmonary embolus (PE), deep venous thrombosis (DVT), ileus, infection, loss of reduction and mortality at 6 months.

RESULTS

569 patients admitted to the MTC with a pelvic or acetabular fracture were included in our analysis. Underweight patients had a statistically significant increase in mortality both in-hospital (p = 0.019) and at 6 months post injury (p = 0.039) when compared to other BMI groups. No statistical significance was found between these BMI groups comparing morbidity: DVT (p = 0.712), PE (p = 0.736) nor ileus (p = 0.149). Covariate analysis showed that a low BMI was associated with triple the in-hospital mortality after correction for age and energy of injury (adjusted OR 3.028, 95% CI 1.059-8.659).

CONCLUSION

This is the first published study that demonstrates a statistically significant increase in mortality in patients with pelvic or acetabular fractures who are underweight. Surgeons should carefully consider appropriate peri-operative optimisation for these patients. Further investigation into the effects of low BMI and response to trauma is required.

Association of BMI, comorbidities and all-cause mortality by using a baseline mortality risk model

Objective

The association of body mass index (BMI) and all-cause mortality is controversial, frequently referred to as a paradox. Whether the cause is metabolic factors or statistical biases is still controversial. We assessed the association of BMI and all-cause mortality considering a wide range of comorbidities and baseline mortality risk.

Methods

Retrospective cohort study of Olmsted County residents with at least one BMI measurement between 2000–2005, clinical data in the electronic health record and minimum 8 year follow-up or death within this time. The cohort was categorized based on baseline mortality risk: Low, Medium, Medium-high, High and Very-high. All-cause mortality was assessed for BMI intervals of 5 and 0.5 Kg/m².

Results

Of 39,739 subjects (average age 52.6, range 18–89; 38.1% male) 11.86% died during 8-year follow-up. The 8-year all-cause mortality risk had a “U” shape with a flat nadir in all the risk groups. Extreme BMI showed higher risk (BMI <15 = 36.4%, 15 to <20 = 15.4% and ≥45 = 13.7%), while intermediate BMI categories showed a plateau between 10.6 and 12.5%. The increased risk attributed to baseline risk and comorbidities was more obvious than the risk based on BMI increase within the same risk groups.

Conclusions

There is a complex association between BMI and all-cause mortality when evaluated including comorbidities and baseline mortality risk. In general, comorbidities are better predictors of mortality risk except at extreme BMIs. In patients with no or few comorbidities, BMI seems to better define mortality risk. Aggressive management of comorbidities may provide better survival outcome for patients with body mass between normal and moderate obesity.

Association of Body Mass Index on Injuries and Outcomes After Ground-Level Falls

BACKGROUND

The impact of body mass index (BMI) on trauma severity after ground-level falls (GLF) is currently unclear. This study aimed to examine the associations between BMI, injuries, and outcomes after GLF.

STUDY DESIGN

All patients ≥16 years of age injured by GLF were queried from the TQIP database (2013-2017). Exclusions were transfers, emergency department death, AIS 6 in any region, and missing data. Body mass index defined study groups: Underweight (BMI<18.5), Normal (BMI 18.5-24.9), Overweight (25.0-29.9), and Obese (≥30).

RESULTS

After exclusions, 131 570 patients remained for analysis. Most patients had a normal BMI (n = 58 503, 44%). Median ISS was 9 [IQR 9-10] in all groups. The Obese group had significantly lower rates of fractures than the Normal group, particularly femur fractures (53% vs. 64%, P < .001), but required orthopedic surgical intervention more frequently (45% vs. 41%, P < .001). On multivariate analysis, being overweight was protective against mortality (OR .881, P = .005), while obesity was not associated with mortality (OR 1.012, P = .821).

CONCLUSION

Increasing BMI may be protective against both fracture risk and mortality after GLF. However, obese patients require operative fixation more frequently. Particularly as fracture diagnosis may be more challenging in the obese, special care should be taken during their tertiary surveys after GLF to ensure injuries are not missed.

Body Mass Index and Mortality in Blunt Trauma: The Right BMI can be Protective

BACKGROUND

There are limited studies examining the role of BMI on mortality in the trauma population. The aim of this study was to analyze whether the "obesity paradox" exists in non-elderly patients with blunt trauma.

METHODS

A retrospective study was performed on the Trauma Quality Improvement Program (TQIP) database for 2016. All non-elderly patients aged 18-64, with blunt traumatic injuries were identified. A generalized additive model (GAM) was built to assess the association of mortality and BMI adjusted for age, gender, race, and injury severity score (ISS).

RESULTS

28,475 patients (mean age = 42.5, SD = 14.3) were identified. 20,328 (71.4%) were male. Age (p < 0.0001), gender (p < 0.0001), and ISS (p < 0.0001) had significant associations with mortality. After GAM, BMI showed a significant U-shaped association with mortality (EDF = 3.2, p = 0.003). A BMI range of 31.5 ± 0.9 kg/m² was associated with the lowest mortality.

CONCLUSION

High BMI can be a protective factor in mortality within non-elderly patients with blunt trauma. However, underweight or morbid obesity suggest a higher risk of mortality.

Obesity May Require a Higher Level of Trauma Care: A Propensity-Matched Nationwide Cohort Study

OBJECTIVE

Stable patients with less severe injuries are not necessarily triaged to high-level trauma centers according to current guidelines. Obese patients are prone to comorbidities and complications. We hypothesized that stable obese patients with low-energy trauma have lower mortality and fewer complications if treated at Level-I/II trauma centers. Methods: Blunt abdominal trauma (BAT) patients with systolic blood pressures ≥90mmHg, Glasgow coma scale ≥14, and respiratory rates at 10-29 were derived from the National Trauma Data Bank between 2013-2015. Per current triage guidelines, these patients are not necessarily triaged to high-level trauma centers. The relationship between obesity and mortality of stable BAT patients was analyzed. A subset analysis of patients with injury severity scores (ISS) <16 was performed with propensity score matching (PSM) to evaluate outcomes between Level-I/II and Level-III/IV trauma centers. Outcomes of obese patients were compared between Level-I/II and Level-III/IV trauma centers. Non-obese patients were analyzed as a control group using a similar PSM cohort analysis. Results: 48,043 stable BAT patients in 707 trauma centers were evaluated. Non-survivors had a significantly higher body mass index (BMI) (28.7 vs. 26.9, p < 0.001) and higher proportion of obesity (35.6% vs. 26.5%, p < 0.001) than survivors. After a PSM (1,502 obese patients: 751 in Level-I/II trauma centers and 751 in Level-III/IV trauma centers), obese patients treated in Level-I/II trauma centers had significantly lower complication rates than obese patients treated in other trauma centers (20.2% vs. 26.6%, standardized difference = 0.151). The complication rate of obese patients treated at Level-I/II trauma centers was 20.6% lower than obese patients treated at other trauma centers. Conclusion: Obesity plays a role in the mortality of stable BAT patients. Obese patients with ISS < 16 have lower complication rates at Level-I/II trauma centers compared to obese patients treated at other trauma centers. Obesity may be a consideration for triaging to Level-I/II trauma centers.