Body mass index is associated with hospital mortality in critically ill patients: an observational cohort study. Crit Care Med. 2013;41:1878-1883. [PMID: 23685638 DOI: 10.1097/ccm.0b013e31828a2aa1]

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.

PReoperative very low-Energy diets for obese PAtients undergoing non-bariatric surgery Randomized Evaluation (PREPARE): a protocol for a pilot randomized controlled trial

BACKGROUND

Patients with obesity presenting in need of surgical intervention are at 2-to-sixfold higher risk of prolonged hospitalization, infectious morbidity, venous thromboembolism, and more. To mitigate some of these concerns, prescribed preoperative weight loss via very low-energy diets (VLEDs) has become a standard of care for patients with obesity undergoing bariatric surgery. While VLEDs have become standard prior to bariatric surgery, their application in other surgical settings remains limited. A large, definitive trial is required to resolve the uncertainty surrounding their use in these patients. Prior to a definitive trial to compare the efficacy of VLEDs in patients with obesity undergoing major non-bariatric surgery, we require a pilot trial. We argue a pilot trial will provide the following critical feasibility insights: (1) assessment of recruitment ability, (2) evaluation of adherence to VLED regimens, and (3) assessment of our ability follow patients completely.

METHODS

The proposed trial will be a multi-center, surgeon, outcome assessor, and data-analyst blinded, parallel pilot randomized controlled trial (RCT). Patients older than 18 years of age with a body mass index (BMI) of greater than 30 kg/m2 undergoing major elective non-bariatric surgery will be eligible for inclusion. Consecutive patients will be allocated 1:1 according to a computer-generated randomization schedule. Randomization will be stratified by center and will employ randomly permutated blocks. All patients in the intervention group will receive standard patient counseling on weight loss and an active VLED protocol. The preoperative VLED protocol will utilize commercially available weight loss products for three weeks preoperatively. The primary outcomes (randomization percentage, recruitment rate, intervention adherence, follow-up completion, network development) will assess feasibility. Descriptive statistics will be used to characterize the study sample.

DISCUSSION

The PREPARE pilot RCT will aim to provide feasibility and safety data that will allow for the successful completion of the definitive PREPARE trial that has the potential to provide practice changing data pertaining to the regular use of VLEDs as a means of pre-habilitation for patients with obesity undergoing major non-bariatric surgery.

TRIAL REGISTRATION

This study was registered on ClinicalTrials.gov (reference #NCT05918471) on June 23, 2023.

Pericardial Fat Is Associated With Less Severe Multiorgan Failure Over Time in Patients With Coronavirus Disease-19: The Maastricht Intensive Care COVID Cohort

PURPOSE

Pericardial fat (PF) and epicardial adipose tissue (EAT) may enhance the proinflammatory response in corona virus-19 (COVID-19) patients. Higher PF and EAT volumes might result in multiorgan failure and explain unfavorable trajectories.The aim of this study was to examine the association between the volume of PF and EAT and multiorgan failure over time.

MATERIALS AND METHODS

All mechanically ventilated COVID-19 patients with an available chest computed tomography were prospectively included (March-June 2020). PF and EAT volumes were quantified using chest computed tomography scans. Patients were categorized into sex-specific PF and EAT tertiles. Variables to calculate Sequential Organ Failure Assessment (SOFA) scores were collected daily to indicate multiorgan failure. Linear mixed-effects regression was used to investigate the association between tertiles for PF and EAT volumes separately and serial SOFA scores over time. All models were adjusted.

RESULTS

Sixty-three patients were divided into PF and EAT tertiles, with median PF volumes of 131.4 mL (IQR [interquartile range]: 115.7, 143.2 mL), 199.8 mL (IQR: 175.9, 221.6 mL), and 318.8 mL (IQR: 281.9, 376.8 mL) and median EAT volumes of 69.6 mL (IQR: 57.0, 79.4 mL), 107.9 mL (IQR: 104.6, 115.1 mL), and 163.8 mL (IQR: 146.5, 203.1 mL). Patients in the highest PF tertile had a statistically significantly lower SOFA score over time (1.3 [-2.5, -0.1], P =0.033) compared with the lowest PF tertile. EAT tertiles were not significantly associated with SOFA scores over time.

CONCLUSION

A higher PF volume is associated with less multiorgan failure in mechanically ventilated COVID-19 patients. EAT volumes were not associated with multiorgan failure.

Specific and Non-specific Aspects and Future Challenges of ICU Care Among COVID-19 Patients with Obesity: A Narrative Review

PURPOSE OF REVIEW

Since the end of 2019, the coronavirus disease 2019 (COVID-19) pandemic has infected nearly 800 million people and caused almost seven million deaths. Obesity was quickly identified as a risk factor for severe COVID-19, ICU admission, acute respiratory distress syndrome, organ support including mechanical ventilation and prolonged length of stay. The relationship among obesity; COVID-19; and respiratory, thrombotic, and renal complications upon admission to the ICU is unclear.

RECENT FINDINGS

The predominant effect of a hyperinflammatory status or a cytokine storm has been suggested in patients with obesity, but more recent studies have challenged this hypothesis. Numerous studies have also shown increased mortality among critically ill patients with obesity and COVID-19, casting doubt on the obesity paradox, with survival advantages with overweight and mild obesity being reported in other ICU syndromes. Finally, it is now clear that the increase in the global prevalence of overweight and obesity is a major public health issue that must be accompanied by a transformation of our ICUs, both in terms of equipment and human resources. Research must also focus more on these patients to improve their care. In this review, we focused on the central role of obesity in critically ill patients during this pandemic, highlighting its specificities during their stay in the ICU, identifying the lessons we have learned, and identifying areas for future research as well as the future challenges for ICU activity.

The impact of obesity on ventilator-associated pneumonia, a US nationwide study

BACKGROUND

Ventilator-associated pneumonia (VAP) is one of the leading causes of mortality in patients with critical care illness. Since obesity is highly prevalent, we wanted to study its impact on the outcomes of patients who develop VAP.

METHODS

Using the National Inpatient Sample (NIS) database from 2017 to 2020, we conducted a retrospective study of adult patients with a principal diagnosis of VAP with a secondary diagnosis with or without obesity according to 10th revision of the International Statistical Classification of Diseases (ICD-10) codes. Several demographics, including age, race, and gender, were analyzed. The primary endpoint was mortality, while the secondary endpoints included tracheostomy, length of stay in days, and patient charge in dollars. Multivariate logistic regression model analysis was used to adjust for confounders, with a p-value less than 0.05 considered statistically significant.

RESULTS

The study included 3832 patients with VAP, 395 of whom had obesity. The mean age in both groups was around 58 years, and 68% of the group with obesity were females compared to 40% in females in the group without obesity. Statistically significant comorbidities in the obesity group included a Charlson Comorbidity Index score of three and above, diabetes mellitus, hypertension, chronic kidney disease, and sleep apnea. Rates and odds of mortality were not significantly higher in the collective obesity group 39 (10%) vs. 336 (8.5%), p-value 0.62, adjusted odds ratio 1.2, p-value 0.61). The rates and odds of tracheostomy were higher in the obesity group but not statistically significant. Obese patients were also found to have a longer hospitalization. Upon subanalysis of the data, no evidence of racial disparities was found in the care of VAP for both the obese and control groups.

CONCLUSIONS

Obesity was not found to be an independent risk factor for worse outcomes in patients who develop VAP in the intensive care unit.

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.

Obesity and Extracorporeal Membrane Oxygenation (ECMO): Analysis of Outcomes

Traditionally, patients with obesity have been deemed ineligible for extracorporeal life support (ELS) therapies such as extracorporeal membrane oxygenation (ECMO), given the association of obesity with chronic health conditions that contribute to increased morbidity and mortality. Nevertheless, a growing body of literature suggests the feasibility, efficacy, and safety of ECMO in the obese population. This review provides an in-depth analysis of the current literature assessing the effects of obesity on outcomes among patients supported with ECMO (venovenous [VV] ECMO in noncoronavirus disease 2019 and coronavirus disease 2019 acute respiratory distress syndrome, venoarterial [VA] ECMO, and combined VV and VA ECMO), offer a possible explanation of the current findings on the basis of the obesity paradox phenomenon, provides a framework for future studies addressing the use of ELS therapies in the obese patient population, and provides guidance from the literature for many of the challenges related to initiating, maintaining, and weaning ELS therapy in patients with obesity.

Continuous Renal Replacement Therapy and Mortality in Critically Ill Obese Adults

IMPORTANCE

The outcomes of critically ill adults with obesity on continuous renal replacement therapy (CRRT) are poorly characterized. The impact of CRRT dose on these outcomes is uncertain.

OBJECTIVES

This study aimed to determine if obesity conferred a survival advantage for critically ill adults with acute kidney injury (AKI) on CRRT. Secondarily, we evaluated whether the dose of CRRT predicted mortality in this population.

DESIGN SETTING AND PARTICIPANTS

A retrospective, observational cohort study performed at an academic medical center in Minnesota. The study population included critically ill adults with AKI managed with CRRT.

MAIN OUTCOMES AND MEASURES

The primary outcome of 30-day mortality was compared between obese (body mass index [BMI] ≥ 30 kg/m2) and nonobese (BMI < 30 kg/m2) patients. Multivariable regression assessed was used to assess CRRT dose as a predictor of outcomes. An analysis included dose indexed according to actual body weight (ABW), adjusted body weight (AdjBW), or ideal body weight (IBW).

RESULTS

Among 1033 included patients, the median (interquartile range) BMI was 26 kg/m2 (23-28 kg/m2) in the nonobese group and 36 kg/m2 (32-41 kg/m2) in the obese group. Mortality was similar between groups at 30 days (54% vs. 48%; p = 0.06) but lower in the obese group at 90 days (62% vs. 55%; p = 0.02). CRRT dose predicted an increase in mortality when indexed according to ABW or AdjBW (hazard ratio [HR], 1.2-1.16) but not IBW (HR, 1.04).

CONCLUSIONS AND RELEVANCE

In critically ill adults with AKI requiring CRRT, short-term mortality appeared lower in obese patients compared with nonobese patients. Among weight calculations, IBW appears to be preferred to promote safe CRRT dosing in obese patients.

Validating a linear regression equation using mid-upper arm circumference to predict body mass index

BACKGROUND

Estimating body mass index (BMI) in hospitalised patients for nutritional assessment is challenging when measurement of weight and height is not feasible. The study aimed to validate a previously published regression equation to predict BMI using mid-upper arm circumference (MUAC). We also evaluated the proposed global MUAC cut-off of ≤24 cm to detect undernutrition.

METHODS

We measured standing height, weight, and MUAC prospectively in a sample of stable patients. Agreement between calculated and predicted BMI was evaluated using Bland-Altman analysis.

RESULTS

We studied 201 patients; 102 (51%) were male. Median (IQR age was 42 (29-50) years. 95% limits of agreement between predicted and calculated BMI were +0.6767 to +1.712 and the bias was +1.076. MUAC ≤24 cm was 97% sensitive and 83% specific to detect undernutrition.

CONCLUSION

BMI derived from MUAC had poor calibration for estimating actual BMI. However, low MUAC has good discriminative accuracy to detect undernutrition.

Visceral obesity measured using computed tomography scans: No significant association with mortality in critically ill patients

INTRODUCTION

The association between obesity and outcome in critical illness is unclear. Since the amount of visceral adipose tissue(VAT) rather than BMI mediates the health effects of obesity we aimed to investigate the association between visceral obesity, BMI and 90-day mortality in critically ill patients.

METHOD

In 555 critically ill patients (68% male), the VAT Index(VATI) was measured using Computed Tomography scans on the level of vertebra L3. The association between visceral obesity, BMI and 90-day mortality was investigated using univariable and multivariable analyses, correcting for age, sex, APACHE II score, sarcopenia and muscle quality.

RESULTS

Visceral obesity was present in 48.1% of the patients and its prevalence was similar in males and females. Mortality was similar amongst patients with and without visceral obesity (27.7% vs 24.0%, p = 0.31). The corrected odds ratio of 90-day mortality for visceral obesity was 0.667 (95%CI 0.424-1.049, p = 0.080). Using normal BMI as reference, the corrected odds ratio for overweight was 0.721 (95%CI 0.447-1.164 p = 0.181) and for obesity 0.462 (95%CI 0.208-1.027, p = 0.058).

CONCLUSION

No significant association of visceral obesity and BMI with 90-day mortality was observed in critically ill patients, although obesity and visceral obesity tended to be associated with improved 90-day mortality.

Associations of body mass index with severe outcomes of COVID-19 among critically ill elderly patients: A prospective study

Background and Aim

Few studies assessed the associations of overweight and obesity with severe outcomes of coronavirus disease 2019 (COVID-19) among elderly patients. This study was conducted to assess overweight and obesity in relation to risk of mortality, delirium, invasive mechanical ventilation (IMV) requirement during treatment, re-hospitalization, prolonged hospitalization, and ICU admission among elderly patients with COVID-19.

Methods

This was a single-center prospective study that was done on 310 elderly patients with COVID-19 hospitalized in the intensive care unit (ICU). We collected data on demographic characteristics, laboratory parameters, nutritional status, blood pressure, comorbidities, medications, and types of mechanical ventilation at baseline. Patients were followed up during ICU admission and until 45 days after the first visit, and data on delirium incidence, mortality, need for a form of mechanical ventilation, discharge day from ICU and hospital, and re-hospitalization were recorded for each patient.

Results

During the follow-up period, we recorded 190 deaths, 217 cases of delirium, and 35 patients who required IMV during treatment. After controlling for potential confounders, a significant association was found between obesity and delirium such that obese patients with COVID-19 had a 62% higher risk of delirium compared with normal-weight patients (HR: 1.62, 95% CI: 1.02-2.57). This association was not observed for overweight. In terms of other outcomes including ICU/45-day mortality, IMV therapy during treatment, re-hospitalization, prolonged hospitalization, and ICU admission, we found no significant association with overweight and obesity either before or after controlling for potential confounders.

Conclusion

We found that obesity may be a risk factor for delirium among critically ill elderly patients with COVID-19.

The physiology of failure: Identifying risk factors for mortality in emergency general surgery patients using a regional health system integrated electronic medical record

BACKGROUND

Emergency general surgery (EGS) patients have increased mortality risk compared with elective counterparts. Recent studies on risk factors have largely used national data sets limited to administrative data. Our aim was to examine risk factors in an integrated regional health system EGS database, including clinical and administrative data, hypothesizing that this novel process would identify clinical variables as important risk factors for mortality.

METHODS

Our nine-hospital health system's billing data were queried for EGS International Classification of Disease codes between 2013 and 2018. Codes were grouped by diagnosis, and urgent or emergent encounters were included and merged with electronic medical record clinical data. Outcomes assessed were inpatient and 1-year mortality. Standard and multivariable statistics evaluated factors associated with mortality.

RESULTS

There were 253,331 EGS admissions with 3.6% inpatient mortality rate. Patients who suffered inpatient and 1-year mortality were older, more likely to be underweight, and have neutropenia or elevated lactate. On multivariable analysis for inpatient mortality: age (odds ratio [OR], 1.7-6.7), underweight body mass index (OR, 1.6), transfer admission (OR, 1.8), leukopenia (OR, 2.0), elevated lactate (OR, 1.8), and ventilator requirement (OR, 7.1) remained associated with increased risk. Adjusted analysis for 1-year mortality demonstrated similar findings, with highest risk associated with older age (OR, 2.8-14.6), underweight body mass index (OR, 2.3), neutropenia (OR, 2.0), and tachycardia (OR, 1.7).

CONCLUSION

After controlling for patient and disease characteristics available in administrative databases, clinical variables remained significantly associated with mortality. This novel yet simple process allows for easy identification of clinical data points imperative to the study of EGS diagnoses that are critical in understanding factors that impact mortality.

LEVEL OF EVIDENCE

Prognostic and Epidemiologic; Level III.

Association between obesity and COVID-19 mortality and length of stay in intensive care unit patients in Brazil: a retrospective cohort study

The present study aimed to evaluate the association between obesity and COVID-19 mortality and length of stay in ICU patients, and how these associations were modified by age groups. We performed a retrospective multicenter cohort study with data obtained from a hospital-based registry. The sample consisted of 8183 ICU hospitalized patients who tested positive for SARS-CoV-2. Cox proportional models were used to evaluate the association between BMI categories and COVID-19 mortality and generalized linear models for the length of stay in the ICU. After adjusting for confounders, those in the younger group with severe obesity had an increased risk of COVID-19 mortality compared to those with normal/overweight (HR 1.27; 95% CI 1.01–1.61). An increased risk of death was also observed for patients with underweight (HR 3.74; 95% CI 1.39–10.07). For patients aged ≥ 60 year, mild/moderate obesity was associated with reduced mortality risk (HR 0.87; 95% CI 0.78–0.97). For the age group < 60 year, the length of stay in ICU for those patients with severe obesity was 35% higher compared to the normal/overweight category (e^β 1.35; 95% CI 1.21–1.51). Conversely, for the survivors in the underweight category, the length of stay in ICU was 51% lower compared to the normal/overweight group (e^β 0.49; 95% CI 0.31–0.78). In the age group ≥ 60 year, mild/moderate obesity was associated with an increased length of stay in the ICU (e^β 1.10; 95% CI 1.01–1.21), adjusting for confounders. These findings could be helpful for health professionals to identify subgroups at higher risk for worse outcomes.

A nomogram to predict prolonged stay of obesity patients with sepsis in ICU: Relevancy for predictive, personalized, preventive, and participatory healthcare strategies

Objective

In an era of increasingly expensive intensive care costs, it is essential to evaluate early whether the length of stay (LOS) in the intensive care unit (ICU) of obesity patients with sepsis will be prolonged. On the one hand, it can reduce costs; on the other hand, it can reduce nosocomial infection. Therefore, this study aimed to verify whether ICU prolonged LOS was significantly associated with poor prognosis poor in obesity patients with sepsis and develop a simple prediction model to personalize the risk of ICU prolonged LOS for obesity patients with sepsis.

Method

In total, 14,483 patients from the eICU Collaborative Research Database were randomized to the training set (3,606 patients) and validation set (1,600 patients). The potential predictors of ICU prolonged LOS among various factors were identified using logistic regression analysis. For internal and external validation, a nomogram was developed and performed.

Results

ICU prolonged LOS was defined as the third quartile of ICU LOS or more for all sepsis patients and demonstrated to be significantly associated with the mortality in ICU by logistic regression analysis. When entering the ICU, seven independent risk factors were identified: maximum white blood cell, minimum white blood cell, use of ventilation, Glasgow Coma Scale, minimum albumin, maximum respiratory rate, and minimum red blood cell distribution width. In the internal validation set, the area under the curve was 0.73, while in the external validation set, it was 0.78. The calibration curves showed that this model predicted probability due to actually observed probability. Furthermore, the decision curve analysis and clinical impact curve showed that the nomogram had a high clinical net benefit.

Conclusion

In obesity patients with sepsis, we created a novel nomogram to predict the risk of ICU prolonged LOS. This prediction model is accurate and reliable, and it can assist patients and clinicians in determining prognosis and making clinical decisions.

New body mass index for predicting prognosis in patients with antineutrophil cytoplasmic antibody‐associated vasculitis

Objectives

Method

Results

Conclusion

The Impact of Obesity on Sudden Cardiac Death Risk

PURPOSE OF REVIEW

We aimed to describe the epidemiology of sudden cardiac death (SCD) in the obese, elaborating on the potential pathophysiological mechanisms linking obesity, SCD, and the outcomes in SCD survivors, as well as looking into the intriguing "obesity paradox" in these patients.

RECENT FINDINGS

Several studies show increased mortality in patients with BMI > 30 kg/m² admitted to the hospital following SCD. At the same time, other studies have implied that the "obesity paradox," described in various cardiovascular conditions, applies to patients admitted after SCD, showing lower mortality in the obese compared to normal weight and underweight patients. We found a significant body of evidence to support that while obesity increases the risk for SCD, the outcomes of obese patients post SCD are better. These findings should not be interpreted as supporting weight gain, as it is always better to prevent the "disaster" from happening than to improve your chances of surviving it. Obesity is shown to be significantly associated with increased risk for SCD; however, there is a growing body of evidence, supporting the "obesity paradox" in the survival of SCD victims. Prospectively, well-designed studies are needed to confirm these findings.

Obesity attenuates inflammation, protein catabolism, dyslipidaemia, and muscle weakness during sepsis, independent of leptin

BACKGROUND

Muscle weakness is a frequently occurring complication of sepsis, associated with increased morbidity and mortality. Interestingly, obesity attenuates sepsis-induced muscle wasting and weakness. As the adipokine leptin is strongly elevated in obesity and has been shown to affect muscle homeostasis in non-septic conditions, we aimed to investigate whether leptin mediates the protective effect of obesity on sepsis-induced muscle weakness.

METHODS

In a mouse model of sepsis, we investigated the effects of genetic leptin inactivation in obese mice (leptin-deficient obese mice vs. diet-induced obese mice) and of leptin supplementation in lean mice (n = 110). We assessed impact on survival, body weight and composition, markers of muscle wasting and weakness, inflammation, and lipid metabolism. In human lean and overweight/obese intensive care unit (ICU) patients, we assessed markers of protein catabolism (n = 1388) and serum leptin (n = 150).

RESULTS

Sepsis mortality was highest in leptin-deficient obese mice (53% vs. 23% in diet-induced obese mice and 37% in lean mice, P = 0.03). Irrespective of leptin, after 5 days of sepsis, lean mice lost double the amount of lean body mass than obese mice (P < 0.0005). Also, irrespective of leptin, obese mice maintained specific muscle force up to healthy levels (P = 0.3) whereas lean mice suffered from reduced specific muscle force (72% of healthy controls, P < 0.0002). As compared with lean septic mice, both obese septic groups had less muscle atrophy, liver amino acid catabolism, and inflammation with a 50% lower plasma TNFα increase (P < 0.005). Conversely, again mainly irrespective of leptin, obese mice lost double amount of fat mass than lean mice after 5 days of sepsis (P < 0.0001), showed signs of increased lipolysis and ketogenesis, and had higher plasma HDL and LDL lipoprotein concentrations (P ≤ 0.01 for all). Muscle fibre type composition was not altered during sepsis, but a higher atrophy sensitivity of type IIb fibres compared with IIa and IIx fibres was observed, independent of obesity or leptin. After 5 days of critical illness, serum leptin was higher (P < 0.0001) and the net waste of nitrogen (P = 0.006) and plasma urea-to-creatinine ratio (P < 0.0001) was lower in overweight/obese compared with lean ICU human patients.

CONCLUSIONS

Leptin did not mediate the protective effect of obesity against sepsis-induced muscle wasting and weakness in mice. Instead, obesity-independent of leptin-attenuated inflammation, protein catabolism, and dyslipidaemia, pathways that may play a role in the observed muscle protection.

Nutritional risk and clinical outcomes in critically ill adult patients with COVID-19

INTRODUCTION

the COVID-19 pandemic put the world's population at risk. As the relationship between nutritional risk and clinical outcomes in critically ill patients with COVID-19 is still poorly understood, a multidisciplinary research team of the Argentine Society of Intensive Care (SATI) conducted a multicenter study aimed to define nutritional features, and to evaluate the relationship between nutritional risk and relevant clinical outcomes for COVID-19 patients in an intensive care unit (ICU).

METHODS

a multicenter, prospective, observational study including twelve Argentinian ICUs was conducted between March and October 2020. Inclusion criteria were: adult patients older than 18 years who were admitted to the ICU with a COVID-19 diagnosis were included. Clinical data included comorbidities scores, and nutritional screening tools such as the Subjective Global Assessment (SGA), the Nutritional Risk Screening (NRS) 2002, and the modified NUTRIC score (mNUTRIC SCORE) were used. In addition, clinical outcomes including overall mortality, mechanical ventilation (MV) days, and ICU and hospital length of stay (LOS) were recorded.

RESULTS

a total of 285 ICU patients met our inclusion criteria. Mean age was 61.24 (SD = 14.6) years; APACHE-II, 14.2 (SD = 6.6); Charlson Comorbidity Index (CCI), 2.3 (SD = 2.3). Most patients were admitted from the emergency room to the ICU. Hypertension, obesity, and diabetes were the most common comorbidities. Nutritional assessment showed that 36.9 % were SGA B+C, and 46 % were obese. Mean ICU LOS was 22.2 (SD = 19.5), and hospital LOS was 28.1 (SD = 21.9) days. Of all patients, 90.2 % underwent MV, and MV days were 20.6 (SD = 15.6). The univariate and multivariate analyses showed that risk factors for COVID-19 mortality were (odds ratio [95 % confidence interval]): SGA score of B or C: 2.13 [1.11-4.06], and NRS 2002 ≥ 3: 2.25 [1.01-5.01].

CONCLUSIONS

in the present study, nutritional status (SGA) and NRS 2002 were major mortality risk factors for CODIV-19 patients in the ICU.

Albumin-Globulin Ratio Is an Independent Determinant of 28-Day Mortality in Patients with Critical Illness

Background

Critical illness in the intensive care unit (ICU) has been a global health priority. Systemic nutritional status has turned out to be related to the prognosis of critically ill patients. The albumin-globulin ratio (AGR) has been reported to be a novel prognostic factor of many diseases. This study is aimed at investigating whether the AGR could predict the mortality risk in critically ill patients.

Methods

We enrolled 582 adult patients admitted to the respiratory intensive care unit (RICU). We collected the clinical and laboratory data. X-tile software was used to determine the optimal cut-off values for the AGR. Patients were divided into three groups according to the AGR (low AGR group with AGR < 0.8, medium AGR group with AGR ranging from 0.8 to 1.1, and high AGR group with AGR > 1.1). Kaplan-Meier analysis was used for survival analysis. A Cox proportional hazard model was applied to the univariate and multivariate analyses for the potential predictors associated with survival.

Results

Our present study showed that the AGR was related to the 28-day survival of critically ill patients in the RICU. The rate of pneumonia in the low AGR group was significantly higher than that in the other groups. Patients with a lower AGR present an increased risk of 28-day mortality compared to patients with a higher AGR. Cox regression analysis showed that the AGR might be an independent predictor of prognosis to 28-day survival in critically ill patients in the RICU. Medium and high AGR values remained independently associated with better 28-day survival than low AGR values (HR: 0.484 (0.263-0.892) (p = 0.02); HR: 0.332 (0.166-0.665) (p = 0.002)).

Conclusion

The AGR might be an independent predictor of prognosis in critically ill patients.

Impact of peripheral muscle strength on prognosis after extubation and functional outcomes in critically ill patients: a feasibility study

The influence of peripheral muscle strength on prognosis after extubation and subsequent functional outcomes is not evident. The objectives of this study were to determine (1) whether peripheral muscle strength can be used as a predictor for patients' prognoses after extubation, and (2) whether the peripheral muscle strength before extubation is correlated with patients' subsequent ambulation ability and in-hospital mortality. This study was a prospective observational cohort study. A hand-held dynamometer was used for evaluated the muscle strength of the biceps and quadriceps right before extubation. Besides, after the patients had been transferred from the ICU to the general ward, a 2-minute walk test was performed. A total of 52 patients were enrolled in this study, and the rate of extubation failure was 15%. The muscle strength of the quadriceps was significantly correlated with the prognosis after extubation, 48% of the patients were able to ambulate after being transferred to the general ward. The overall mortality rate was 11%, and there was a significant correlation between the biceps muscle strength and in-hospital mortality. Peripheral muscle strength may serve as an important predictor of a patients' prognoses after extubation. Poor peripheral muscle strength is indicative of not only a higher risk of re-intubation but also higher in-hospital mortality and poorer functional outcomes.Trial registration: ISRCTN16370134. Registered 30 May 2019, prospectively registered. https://www.isrctn.com/ISRCTN16370134 .

Association between Advanced Lung Inflammation Index and 30-Day Mortality in Patients with Acute Respiratory Distress Syndrome

Background and objectives: The advanced lung inflammation index (ALI) was developed to assess the degree of systemic inflammation and has an association with prognosis in patients with lung malignancy. The prognostic value of ALI has not yet been evaluated in patients with acute respiratory distress syndrome (ARDS). Materials and Methods: Between January 2014 and May 2018, patients with ARDS in the medical intensive care unit (ICU) were reviewed retrospectively. The ALI value was calculated as the (body mass index × serum albumin level)/neutrophil-lymphocyte ratio. The cut-off value for distinguishing low from high ALI was defined according to receiver-operating characteristic curve analysis. Results: A total of 164 patients were analyzed. Their median age was 73 years, and 73% was male. The main cause of ARDS was pneumonia (95.7%, 157/164). ICU and in-hospital mortality rates were 59.8% (98/164) and 64% (105/164), respectively. The 30 day mortality was 60.9% (100/164). The median ALI value in non-survivors was lower than that in survivors at 30 day (3.81 vs. 7.39, p = 0.005). In multivariate analysis, low ALI value (≤5.38) was associated with increased 30 day mortality (odds ratio, 2.944, confidence interval 1.178–7.355, p = 0.021). Conclusions: A low ALI value was associated with increased 30 day mortality in patients with ARDS.

Association of body mass index with morbidity in patients hospitalised with COVID-19

PURPOSE

To evaluate the association between body mass index (BMI) and clinical outcomes other than death in patients hospitalised and intubated with COVID-19.

METHODS

This is a single-centre cohort study of adults with COVID-19 admitted to New York Presbyterian Hospital-Weill Cornell Medicine from 3 March 2020 through 15 May 2020. Baseline and outcome variables, as well as lab and ventilatory parameters, were generated for the admitted and intubated cohorts after stratifying by BMI category. Linear regression models were used for continuous, and logistic regression models were used for categorical outcomes.

RESULTS

The study included 1337 admitted patients with a subset of 407 intubated patients. Among admitted patients, hospital length of stay (LOS) and home discharge was not significantly different across BMI categories independent of demographic characteristics and comorbidities. In the intubated cohort, there was no difference in in-hospital events and treatments, including renal replacement therapy, neuromuscular blockade and prone positioning. Ventilatory ratio was higher with increasing BMI on days 1, 3 and 7. There was no significant difference in ventilator free days (VFD) at 28 or 60 days, need for tracheostomy, hospital LOS, and discharge disposition based on BMI in the intubated cohort after adjustment.

CONCLUSIONS

In our COVID-19 population, there was no association between obesity and morbidity outcomes, such as hospital LOS, home discharge or VFD. Further research is needed to clarify the mechanisms underlying the reported effects of BMI on outcomes, which may be population dependent.

Body Mass Index and Mortality in Coronavirus Disease 2019 and Other Diseases: A Cohort Study in 35,506 ICU Patients

Supplemental Digital Content is available in the text.

OBJECTIVES:

Obesity is a risk factor for severe coronavirus disease 2019 and might play a role in its pathophysiology. It is unknown whether body mass index is related to clinical outcome following ICU admission, as observed in various other categories of critically ill patients. We investigated the relationship between body mass index and inhospital mortality in critically ill coronavirus disease 2019 patients and in cohorts of ICU patients with non-severe acute respiratory syndrome coronavirus 2 viral pneumonia, bacterial pneumonia, and multiple trauma.

DESIGN:

Multicenter observational cohort study.

SETTING:

Eighty-two Dutch ICUs participating in the Dutch National Intensive Care Evaluation quality registry.

PATIENTS:

Thirty-five–thousand five-hundred six critically ill patients.

INTERVENTIONS:

None.

MEASUREMENTS AND MAIN RESULTS:

Patient characteristics and clinical outcomes were compared between four cohorts (coronavirus disease 2019, nonsevere acute respiratory syndrome coronavirus 2 viral pneumonia, bacterial pneumonia, and multiple trauma patients) and between body mass index categories within cohorts. Adjusted analyses of the relationship between body mass index and inhospital mortality within each cohort were performed using multivariable logistic regression. Coronavirus disease 2019 patients were more likely male, had a higher body mass index, lower Pao₂/Fio₂ ratio, and were more likely mechanically ventilated during the first 24 hours in the ICU compared with the other cohorts. Coronavirus disease 2019 patients had longer ICU and hospital length of stay, and higher inhospital mortality. Odds ratios for inhospital mortality for patients with body mass index greater than or equal to 35 kg/m² compared with normal weight in the coronavirus disease 2019, nonsevere acute respiratory syndrome coronavirus 2 viral pneumonia, bacterial pneumonia, and trauma cohorts were 1.15 (0.79–1.67), 0.64 (0.43–0.95), 0.73 (0.61–0.87), and 0.81 (0.57–1.15), respectively.

CONCLUSIONS:

The obesity paradox, which is the inverse association between body mass index and mortality in critically ill patients, is not present in ICU patients with coronavirus disease 2019–related respiratory failure, in contrast to nonsevere acute respiratory syndrome coronavirus 2 viral and bacterial respiratory infections.

Relationship Between Body Mass Index and Survival Among Critically Ill Patients With Cirrhosis

BACKGROUND

Obesity paradox is a phenomenon in which obesity increases the risk of obesity-related chronic diseases but paradoxically is associated with improved survival among obese patients with these diagnoses.

OBJECTIVES

The aim of this study was to explore the obesity paradox among critically ill patients with cirrhosis admitted to the Intensive Care Unit.

METHODS

A retrospective cohort of 1,143 consecutive patients with cirrhosis admitted to the ICU between January of 2006 and December of 2015 was analyzed. Primary outcome of interest was in-hospital mortality with secondary end points including ICU and short-term mortality at 30 days post ICU admission.

RESULTS

Logistic regression with generalized additive models was used, controlling for clinically relevant and statistically significant factors to determine the adjusted relationship between body mass index (BMI) and ICU, post-ICU in-hospital, and 30 day mortality following ICU discharge. ICU and hospital length of stay was similar across all BMI classes. Adjusted ICU mortality was also similar when stratified by BMI. However, a significant reduction in post-ICU hospital mortality was observed in class I and II obese patients with cirrhosis (BMI 30-39.9 kg/m²) compared to normal BMI (OR = 0.41; 95% CI, 0.20 to 0.83; P = 0.014). Similarly, overweight (BMI 25-29.9 kg/m²) and class I and II obese patients with cirrhosis had significantly lower 30-day mortality following ICU discharge (OR = 0.52, 95% CI 0.31 to 0.87; P = 0.014; OR = 0.50, 95% CI 0.29 to 0.86; P = 0.012, respectively) compared to those with normal BMI.

CONCLUSION

The signal of obesity paradox is suggested among critically ill patients with cirrhosis.

Body Mass Index Is Associated with the Severity and All-Cause Mortality of Acute Kidney Injury in Critically Ill Patients: An Analysis of a Large Critical Care Database

Background

Acute kidney injury (AKI) is a common clinical syndrome carrying high morbidity and mortality. Body mass index (BMI) is a common health indicator, and a high BMI value-obesity has been shown to be associated with the outcomes of several diseases. However, the relationship between different BMI categories and mortality in all critically ill patients with AKI is unclear and needs further investigation. Therefore, we evaluated the ability of BMI to predict the severity and all-cause mortality of AKI in critically ill patients.

Methods

We extracted clinical data from the MIMIC-III v1.4 database. All adult patients with AKI were initially screened. The baseline data extracted within 24 hours after ICU admission were presented according to WHO BMI categories. Logistic regression models and the Cox proportional hazards models were, respectively, constructed to assess the relationship between BMI and the severity and all-cause mortality of AKI. The generalized additive model (GAM) was used to identify nonlinear relationships as BMI was a continuous variable. The subgroup analyses were performed to further analyze the stability of the association between BMI category and 365-day all-cause mortality of AKI.

Result

A total of 15,174 patients were extracted and were divided into four groups according to BMI. Obese patients were more likely to be young and male. In the fully adjusted logistic regression model, we found that overweight and obesity were significant predictors of AKI stage III (OR, 95 CI: 1.17, 1.05-1.30; 1.32, 1.18-1.47). In the fully adjusted Cox proportional hazards model, overweight and obesity were associated with significantly lower 30-day, 90-day, and 365-day all-cause mortality. The corresponding adjusted HRs (95 CIs) for overweight patients were 0.87 (0.77, 0.99), 0.84 (0.76, 0.93), and 0.80 (0.74, 0.88), and for obese patients, they were 0.87 (0.77, 0.98), 0.79 (0.71, 0.88), and 0.73 (0.66, 0.80), respectively. The subgroup analyses further presented a stable relationship between BMI category and 365-day all-cause mortality.

Conclusions

BMI was independently associated with the severity and all-cause mortality of AKI in critical illness. Overweight and obesity were associated with increased risk of AKI stage III; however, they were predictive of a relatively lower mortality risk in these patients.

Patient-Level Barriers and Facilitators to Early Mobilization and the Relationship With Physical Disability Post-Intensive Care: Part 2 of an Integrative Review Through the Lens of the World Health Organization International Classification of Functioning, Disability, and Health

BACKGROUND

Early mobilization (EM) is associated with reduced physical disability post-intensive care (PD PIC). Yet, contextual factors facilitate or impede delivery of EM in the intensive care unit (ICU). Only 45% of ICUs in the United States routinely practice EM despite its recognized benefits.

OBJECTIVES

To analyze the evidence on the relationship between critical care EM, PD PIC, and personal (patient-level) factors, using the theoretical lens of the World Health Organization's International Classification of Functioning, Disability, and Health (ICF).

METHOD

The Whittemore and Knafl methodology for integrative reviews and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) reporting guidelines were followed. Qualitative, quantitative, and mixed-methods studies (n = 38) that evaluated EM and 1 or more domains of the World Health Organization ICF were included. Quality was appraised using the Mixed-Methods Appraisal Tool. Study characteristics were evaluated for common themes and relationships. The ICF domains and subdomains pertaining to each study were synthesized.

RESULTS

Early mobilization delivery was influenced by personal factors. Deeper sedation level, the presence of delirium, higher patient acuity, the presence of medical devices, and patient weight were identified barriers to EM delivery. Patient engagement in EM was associated with improved delivery. Patients who enjoyed rehabilitation were more likely to demonstrate improvement in functional impairment than those who did not enjoy rehabilitation.

DISCUSSION

Early mobilization is associated with reduced PD PIC, yet numerous contextual factors affect the delivery of EM in the ICU. Further study of patient-level factors and EM must explore the relationship between patient engagement, baseline demographics, and functional status at ICU admission, patient-level considerations for decisions to mobilize, and EM in the ICU. This research is critical to improving the delivery of EM in the ICU and reducing PD PIC.

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

Objective

The obesity paradox is the association of increased survival for overweight and obese patients compared to normal and underweight patients, despite an increased risk of morbidity. The obesity paradox has been demonstrated in many disease states but has yet to be studied in trauma. The objective of this study is to elucidate the presence of the obesity paradox in trauma patients by evaluating the association between BMI and outcomes.

Methods

Using the 2014–2015 National Trauma Database (NTDB), adults were categorized by WHO BMI category. Logistic regression was used to assess the odds of mortality associated with each category, adjusting for statistically significant covariables. Length of stay (LOS), ICU LOS and ventilator days were also analyzed, adjusting for statistically significant covariables.

Results

A total of 415,807 patients were identified. Underweight patients had increased odds of mortality (OR 1.378, p < 0.001 95% CI 1.252–1.514), while being overweight had a protective effect (OR 0.916, p = 0.002 95% CI 0.867–0.968). Class I obesity was not associated with increased mortality compared to normal weight (OR 1.013, p = 0.707 95% CI 0.946–1.085). Class II and Class III obesity were associated with increased mortality risk (Class II OR 1.178, p = 0.001 95% CI 1.069–1.299; Class III OR 1.515, p < 0.001 95% CI 1.368–1.677). Hospital and ICU LOS increased with each successive increase in BMI category above normal weight. Obesity was associated with increased ventilator days; Class I obese patients had a 22% increase in ventilator days (IRR 1.217 95% CI 1.171–1.263), and Class III obese patients had a 54% increase (IRR 1.536 95% CI 1.450–1.627).

Conclusion

The obesity paradox exists in trauma patients. Further investigation is needed to elucidate what specific phenotypic aspects confer this benefit and how these can enhance patient care.

Level of evidence

Level III, prognostic study

White adipose tissue browning in critical illness: A review of the evidence, mechanisms and future perspectives

Observational studies suggest better clinical outcomes following critical illness in patients with overweight and obesity (obesity paradox). An understanding of the morphologic, physiologic and metabolic changes in adipose tissue in critical illness may provide an explanation. Recent studies have demonstrated the transformation of white to brown-like adipocytes due to the "browning process," which has been of interest as a potential novel therapy in obesity during the last decade. The characteristics of the browning of white adipose tissue (WAT) include the appearance of smaller, multilocular adipocytes, increased UCP1 mRNA expression, mitochondrial density and respiratory capacity. These changes have been identified in some critical illnesses, which specifically refers to burns, sepsis and cancer cachexia in this study. The pathophysiological nature of WAT browning, underlying mechanisms, main regulators and potential benefits and harms of this process are interesting new areas that warrants further investigations. In this review, we discuss emerging scientific discipline of adipose tissue physiology in metabolic stress, available data, gaps of knowledge and future perspectives. Future investigations in this field may provide insights into the underlying mechanisms and clinical aspects of browning that may further our understanding of the proposed obesity paradox following critical illness, which may in turn open up opportunities for novel therapies to save lives and improve recovery.

How to ventilate obese patients in the ICU

Obesity is an important risk factor for major complications, morbidity and mortality related to intubation procedures and ventilation in the intensive care unit (ICU). The fall in functional residual capacity promotes airway closure and atelectasis formation. This narrative review presents the impact of obesity on the respiratory system and the key points to optimize airway management, noninvasive and invasive mechanical ventilation in ICU patients with obesity. Non-invasive strategies should first optimize body position with reverse Trendelenburg position or sitting position. Noninvasive ventilation (NIV) is considered as the first-line therapy in patients with obesity having a postoperative acute respiratory failure. Positive pressure pre-oxygenation before the intubation procedure is the method of reference. The use of videolaryngoscopy has to be considered by adequately trained intensivists, especially in patients with several risk factors. Regarding mechanical ventilation in patients with and without acute respiratory distress syndrome (ARDS), low tidal volume (6 ml/kg of predicted body weight) and moderate to high positive end-expiratory pressure (PEEP), with careful recruitment maneuver in selected patients, are advised. Prone positioning is a therapeutic choice in severe ARDS patients with obesity. Prophylactic NIV should be considered after extubation to prevent re-intubation. If obesity increases mortality and risk of ICU admission in the overall population, the impact of obesity on ICU mortality is less clear and several confounding factors have to be taken into account regarding the “obesity ICU paradox”.

Association between Body Mass Index and Short-Term Clinical Outcomes in Critically Ill Patients with Sepsis: A Real-World Study

Background

Obesity is now recognized as one of the major public health threats, especially for patients with a critical illness. However, studies regarding whether and how body mass index (BMI) affects clinical outcomes in patients with sepsis are still scarce and controversial. The aim of our study was to determine the effect of BMI on critically ill patients with sepsis.

Materials and Methods

We performed this study using data from the Medical Information Center for Intensive Care III database. A multivariate Cox regression model was used to assess the independent association of BMI with the primary outcome.

Results

A total of 7,967 patients were enrolled in this study. Firstly, we found that the 28-day mortality was reduced by 22% (HR = 0.78, 95% CI 0.69–0.88) and 13% (HR = 0.87, 95% CI 0.78–0.98) for obese and overweight compared to normal weight, respectively. Subsequently, a U-shaped association of BMI with 28-day mortality was observed in sepsis patients, with the lowest 28-day mortality at the BMI range of 30–40 kg/m². Finally, significant interactions were observed only for sex (P = 0.0071). Male patients with a BMI of 25-30 kg/m² (HR = 0.74, 95% CI 0.63–0.86) and 30-40 kg/m² (HR = 0.63, 95% CI 0.53–0.76) had a significantly lower risk of 28-day mortality.

Conclusions

A U-shaped association of BMI with 28-day mortality in critically ill sepsis patients was found, with the lowest 28-day mortality at a BMI range of 30–40 kg/m². Notably, male patients were protected by a higher BMI more effectively than female patients as males had a significantly lower mortality risk.

Clinical outcomes of difficult-to-wean patients with ventilator dependency at intensive care unit discharge

Background

Ventilator-dependent patients in the intensive care unit (ICU) who are difficult to wean from invasive mechanical ventilation (IMV) have been increasing in number. However, data on the clinical outcomes of difficult-to-wean patients are lacking. We aimed to evaluate clinical outcomes in patients discharged from the ICU with tracheostomy and ventilator dependency.

Methods

We retrospectively investigated clinical course and survival in patients requiring home mechanical ventilation (HMV) with a tracheostomy and difficulty weaning from IMV during medical ICU admission from September 2013 through August 2016 at Severance Hospital, Yonsei University, Seoul, Korea.

Results

Of 84 difficult-to-wean patients who were started on HMV in the medical ICU, 72 survived, were discharged from the ICU, and were included in this analysis. HMV was initiated after a median of 23 days of IMV, and the successful weaning rate was 46% (n=33). In-hospital mortality rate was significantly lower in the successfully weaned group than the unsuccessfully weaned group (0% vs. 23.1%, respectively; P=0.010). Weaning rates were similar according to primary diagnosis, but high body mass index (BMI), low Acute Physiologic Assessment and Chronic Health Evaluation (APACHE) II score at ICU admission, and absence of neuromuscular disease were associated with weaning success. After a median follow-up of 4.6 months (range, 1–27 months) for survivors, 3-month (n=64) and 6-month (n=59) survival rates were 82.5% and 72.2%, respectively. Survival rates were higher in the successfully weaned group than the unsuccessfully weaned group at 3 months (96.4% vs. 69.0%; P=0.017) and 6 months (84.0% vs. 62.1%; P=0.136) following ICU discharge.

Conclusions

In summary, 46% of patients who started HMV were successfully weaned from the ventilator in general wards. High BMI, low APACHE II score, and absence of neuromuscular disease were factors associated with weaning success.

The obesity paradox in critically ill patients: a causal learning approach to a casual finding

Background

While obesity confers an increased risk of death in the general population, numerous studies have reported an association between obesity and improved survival among critically ill patients. This contrary finding has been referred to as the obesity paradox. In this retrospective study, two causal inference approaches were used to address whether the survival of non-obese critically ill patients would have been improved if they had been obese.

Methods

The study cohort comprised 6557 adult critically ill patients hospitalized at the Intensive Care Unit of the Ghent University Hospital between 2015 and 2017. Obesity was defined as a body mass index of ≥ 30 kg/m². Two causal inference approaches were used to estimate the average effect of obesity in the non-obese (AON): a traditional approach that used regression adjustment for confounding and that assumed missingness completely at random and a robust approach that used machine learning within the targeted maximum likelihood estimation framework along with multiple imputation of missing values under the assumption of missingness at random. 1754 (26.8%) patients were discarded in the traditional approach because of at least one missing value for obesity status or confounders.

Results

Obesity was present in 18.9% of patients. The in-hospital mortality was 14.6% in non-obese patients and 13.5% in obese patients. The raw marginal risk difference for in-hospital mortality between obese and non-obese patients was − 1.06% (95% confidence interval (CI) − 3.23 to 1.11%, P = 0.337). The traditional approach resulted in an AON of − 2.48% (95% CI − 4.80 to − 0.15%, P = 0.037), whereas the robust approach yielded an AON of − 0.59% (95% CI − 2.77 to 1.60%, P = 0.599).

Conclusions

A causal inference approach that is robust to residual confounding bias due to model misspecification and selection bias due to missing (at random) data mitigates the obesity paradox observed in critically ill patients, whereas a traditional approach results in even more paradoxical findings. The robust approach does not provide evidence that the survival of non-obese critically ill patients would have been improved if they had been obese.

Program on high value cost-conscious education in intensive care: Educational program on prediction of outcome and cost awareness on Intensive Care admission

BACKGROUND

Intensive Care (ICU) involves extended and long lasting support of vital functions and organs. However, current training programs of ICU residents mainly focus on extended support of vital functions and barely involve training on cost-awareness and outcome. We incorporated an educational program on high-value cost-conscious care for residents and fellows on our ICU and measured the effect of education.

METHODS

A cohort study with factorial survey design, in which ICU residents and fellows were asked to evaluate clinical vignettes, was performed on the mixed surgical-medical ICU of the Amsterdam University Medical Centre. Residents were offered an educational program focusing on outcome and costs of ICU care. Before and after the program they filled out a questionnaire, which consisted of 23 vignettes, in which known predictors of outcome of community acquired pneumonia (CAP), pancreatitis, acute respiratory distress syndrome (ARDS) and cardiac arrest were presented, together with varying patient factors (age, body mass index (BMI), acute kidney failure (AKI) and haemato-oncological malignancy). Participants were asked to either admit the patient or estimate mortality.

RESULTS

BMI, haemato-oncological malignancy and severity of pancreatitis were discriminative for admission to ICU in clinical vignettes on pancreatitis and CAP. After education, only severity of pancreatitis was judged as discriminative. Before the intervention only location of cardiac arrest (in- vs out of hospital) was distinctive for mortality, afterwards this changed to presence of haemato-oncological malignancy.

CONCLUSION

We incorporated an educational program on high-value cost-conscious care in the training of ICU physicians. Based on our vignette study, we conclude that the improvement of knowledge of costs and prognosis after this program was limited.

A retrospective observational study of sarcopenia and outcomes in critically ill patients

Frailty assessment in patients admitted to intensive care is often limited using traditional clinical frailty assessment tools. Opportunistic use of contemporary computed tomography (CT) can provide an objective estimate of low skeletal muscle mass (sarcopenia) as a proxy for frailty. The aim of this study was to establish the prevalence of sarcopenia in an Australian intensive care unit (ICU) population and to examine the relationship between sarcopenia and clinical outcomes. We undertook a single centre retrospective study of 1085 adult patients admitted to a single ICU over 12 months. Patients with a contemporary CT scan including the L3 vertebral body were included. Patients were categorised as sarcopenic or non-sarcopenic using previously published data. A total of 279 patients with a mean age of 67 years had an eligible CT scan; 163 (58%) were male. Higher 30-day mortality was associated with the use of CRRT (continuous renal replacement therapy) during the ICU admission (OR 6.84, P < 0.001) and also associated with lower cross-sectional muscle area (odds ratio (OR) 0.98, P = 0.004). Sarcopenia was found to be highly prevalent in this particular Australian ICU population (68%) and associated with older age (68 versus 55 years, P < 0.001), lower body mass index (27 versus 32 kg m^-2, P < 0.001), more comorbidities (3 versus 2, P = 0.009), and longer stays in hospital (279 versus 223 h, P = 0.043). As a continuous predictor, lumbar muscle mass was associated with 30-day mortality with and without adjusting for other covariates.

Dose-Response Meta-Analysis of the Impact of Body Mass Index on Mortality in the Intensive Care Unit

INTRODUCTION

Both low and high body mass index (BMI) are associated with mortality in the intensive care unit (ICU). Although many studies have been done to determine the relationship between BMI and risk of mortality in the ICU, their results were inconsistent. This study aimed to conduct a dose-response meta-analysis of published observational studies to assess the effect of BMI on the risk of mortality in patients admitted to the ICU.

METHODS

PubMed, Scopus, and Google Scholar were searched to identify articles up to May 2019. A total of 31 relevant articles, with 238,961 patients and a follow-up period of 1 month to 11 years, were analyzed.

RESULTS

Linear analysis showed a 0.6% decrease in mortality rate per unit (kg/m² ) increase in BMI (odds ratio: 0.99; 95% CI, 0.98-0.99). In addition, nonlinear analysis showed a decrease in risk of mortality for a BMI of 35 (P < .001) and then increased the risk of mortality with a BMI > 35 (P < .001).

CONCLUSION

This dose-response meta-analysis revealed that a BMI ≤ 35 can be a protective agent against mortality, but a BMI > 35 is a life-threatening factor in patients admitted to the ICU.

Does Obesity Protect Against Death in Sepsis? A Retrospective Cohort Study of 55,038 Adult Patients

OBJECTIVES

Observational studies suggest obesity is associated with sepsis survival, but these studies are small, fail to adjust for key confounders, measure body mass index at inconsistent time points, and/or use administrative data to define sepsis. To estimate the relationship between body mass index and sepsis mortality using detailed clinical data for case detection and risk adjustment.

DESIGN

Retrospective cohort analysis of a large clinical data repository.

SETTING

One-hundred thirty-nine hospitals in the United States.

PATIENTS

Adult inpatients with sepsis meeting Sepsis-3 criteria.

EXPOSURE

Body mass index in six categories: underweight (body mass index < 18.5 kg/m), normal weight (body mass index = 18.5-24.9 kg/m), overweight (body mass index = 25.0-29.9 kg/m), obese class I (body mass index = 30.0-34.9 kg/m), obese class II (body mass index = 35.0-39.9 kg/m), and obese class III (body mass index ≥ 40 kg/m).

MEASUREMENTS

Multivariate logistic regression with generalized estimating equations to estimate the effect of body mass index category on short-term mortality (in-hospital death or discharge to hospice) adjusting for patient, infection, and hospital-level factors. Sensitivity analyses were conducted in subgroups of age, gender, Elixhauser comorbidity index, Sequential Organ Failure Assessment quartiles, bacteremic sepsis, and ICU admission.

MAIN RESULTS

From 2009 to 2015, we identified 55,038 adults with sepsis and assessable body mass index measurements: 6% underweight, 33% normal weight, 28% overweight, and 33% obese. Crude mortality was inversely proportional to body mass index category: underweight (31%), normal weight (24%), overweight (19%), obese class I (16%), obese class II (16%), and obese class III (14%). Compared with normal weight, the adjusted odds ratio (95% CI) of mortality was 1.62 (1.50-1.74) for underweight, 0.73 (0.70-0.77) for overweight, 0.61 (0.57-0.66) for obese class I, 0.61 (0.55-0.67) for obese class II, and 0.65 (0.59-0.71) for obese class III. Results were consistent in sensitivity analyses.

CONCLUSIONS

In adults with clinically defined sepsis, we demonstrate lower short-term mortality in patients with higher body mass indices compared with those with normal body mass indices (both unadjusted and adjusted analyses) and higher short-term mortality in those with low body mass indices. Understanding how obesity improves survival in sepsis would inform prognostic and therapeutic strategies.

Obesity Paradox in the Burn Patient

Despite the fact that obesity is a known risk factor for comorbidities and complications, there is evidence suggesting a survival advantage for patients classified by body mass index (BMI) as overweight or obese. Investigated in various clinical areas, this “Obesity Paradox” has yet to be explored in the burn patient population. We sought to clarify whether this paradigm exists in burn patients. Data collected on 519 adult patients admitted to an American Burn Association Verified Burn Center between 2009 and 2017 was utilized. Univariable and multivariable logistic regression were used to determine the association between in-hospital mortality and BMI classifications (underweight &lt;18.5 kg/m2, normal 18.5 to 24.9 kg/m2, overweight 25–29.9 kg/m2, obesity class I 30 to 34.9 kg/m2, obesity class II 35 to 39.9 kg/m2, and extreme obesity &gt;40 kg/m2). For every kg/m2 increase in BMI, the odds of death decreased, with an adjusted odds ratio of 0.856 (95% confidence interval [CI] 0.767 to 0.956). When adjusted for total BSA (TBSA), being obesity class I was associated with an adjusted odds ratio of mortality of 0.0166 (95% CI 0.000332 to 0.833). The adjusted odds ratio for mortality for underweight patients was 4.13 (95% CI 0.416 to 41.055). There was no statistically significant difference in odds of mortality between the normal and overweight BMI categories. In conclusion, the obesity paradox exists in burn care: further investigation is needed to elucidate what specific phenotypic aspects confer this benefit and how these can enhance the care of burn patients.

[The obese patient and acute respiratory failure, a challenge for intensive care]

As a result of the constantly increasing epidemic of obesity, it has become a common problem in the intensive care unit. Morbid obesity has numerous consequences for the respiratory system. It affects both respiratory mechanics and pulmonary gas exchange, and dramatically impacts on the patient's management and outcome. With the potential for causing devastating respiratory complications, the particular anatomical and physiological characteristics of the respiratory system of the morbidly obese subject should be carefully taken into consideration. The present article reviews the management of obese patients in respiratory failure, from noninvasive ventilation to tracheostomy, including postural and technical issues, and explains the physiologically based ventilatory strategy both for NIV and invasive mechanical ventilation up to the weaning from the ventilatory support.

Adipose tissue protects against sepsis-induced muscle weakness in mice: from lipolysis to ketones

Background

ICU-acquired weakness is a debilitating consequence of prolonged critical illness that is associated with poor outcome. Recently, premorbid obesity has been shown to protect against such illness-induced muscle wasting and weakness. Here, we hypothesized that this protection was due to increased lipid and ketone availability.

Methods

In a centrally catheterized, fluid-resuscitated, antibiotic-treated mouse model of prolonged sepsis, we compared markers of lipolysis and fatty acid oxidation in lean and obese septic mice (n = 117). Next, we compared markers of muscle wasting and weakness in septic obese wild-type and adipose tissue-specific ATGL knockout (AAKO) mice (n = 73), in lean septic mice receiving either intravenous infusion of lipids or standard parenteral nutrition (PN) (n = 70), and in lean septic mice receiving standard PN supplemented with either the ketone body 3-hydroxybutyrate or isocaloric glucose (n = 49).

Results

Obese septic mice had more pronounced lipolysis (p ≤ 0.05), peripheral fatty acid oxidation (p ≤ 0.05), and ketogenesis (p ≤ 0.05) than lean mice. Blocking lipolysis in obese septic mice caused severely reduced muscle mass (32% loss vs. 15% in wild-type, p < 0.001) and specific maximal muscle force (59% loss vs. 0% in wild-type; p < 0.001). In contrast, intravenous infusion of lipids in lean septic mice maintained specific maximal muscle force up to healthy control levels (p = 0.6), whereas this was reduced with 28% in septic mice receiving standard PN (p = 0.006). Muscle mass was evenly reduced with 29% in both lean septic groups (p < 0.001). Lipid administration enhanced fatty acid oxidation (p ≤ 0.05) and ketogenesis (p < 0.001), but caused unfavorable liver steatosis (p = 0.01) and a deranged lipid profile (p ≤ 0.01). Supplementation of standard PN with 3-hydroxybutyrate also attenuated specific maximal muscle force up to healthy control levels (p = 0.1), but loss of muscle mass could not be prevented (25% loss in both septic groups; p < 0.001). Importantly, this intervention improved muscle regeneration markers (p ≤ 0.05) without the unfavorable side effects seen with lipid infusion.

Conclusions

Obesity-induced muscle protection during sepsis is partly mediated by elevated mobilization and metabolism of endogenous fatty acids. Furthermore, increased availability of ketone bodies, either through ketogenesis or through parenteral infusion, appears to protect against sepsis-induced muscle weakness also in the lean.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2506-6) contains supplementary material, which is available to authorized users.

The paradox prevails: Outcomes are better in critically ill obese patients regardless of the comorbidity burden

During critical illness, obese patients have better outcomes compared to patients with normal BMI, and this is known as the obesity paradox. The difference in comorbidity burden have been implied to be responsible for the paradox. We performed a retrospective review from 2001 to 2012 of critically ill patients from the Medical Information Mart for Intensive Care database. We included 11,433 patients and classified them according to body mass index (BMI) and comorbidity burden (Elixhauser comorbidity measure). The odds of inpatient mortality were lower in obese patients compared to patients with normal BMI; in group with the least comorbidity score (Elixhauser <0) [OR: 0.47, CI (0.28-0.80), p-value 0.006] and higher comorbidity scores, (Elixhauser 1-5) [(OR: 0.66, CI (0.46-0.95), p-value 0.02)] and (Elixhauser 6-13) [OR: 0.69, CI (0.53-0.92), p-value 0.01]. 30-day mortality was also significantly lower in obese patients, in groups with the lowest (Elixhauser <0) [OR:49, CI (0.31-0.77), p-value 0.002] as well as the highest comorbidity burden (Elixhauser >14) [OR:0.59, CI (0.45-0.77), p-value <.001]. Subgroup analysis in patients with various comorbidities showed better outcomes in obese patients. These findings show that the decreased odds of mortality in critically ill obese patients is independent of the comorbidity burden or type of comorbidity.

The association between obesity and outcomes in acute pancreatitis: an individual patient data meta-analysis

OBJECTIVES

There are data to suggest that obesity is associated with local and systemic complications as well as mortality in acute pancreatitis (AP). Cohort studies to date, however, have shown conflicting results from mostly unadjusted analyses. Therefore, we performed an individual patient data meta-analysis with the primary aim to investigate the association between obesity and mortality in AP. Our secondary aim was to investigate the association between obesity and necrosis, organ failure, multiple organ failure, and invasive intervention.

PATIENTS AND METHODS

We systematically searched four electronic databases for prospective studies on obesity and outcomes in AP. Researchers of eligible studies were invited to share individual patient data using a standardized data collection form. All end points were investigated with a one-stage mixed effects Poisson model with random intercepts and forced entry of relevant confounders.

RESULTS

We included five databases with 1302 patients, of whom 418 (32%) were obese. In total, 466 (36%) patients had necrosis, 328 (25%) had organ failure, 188 (14%) had multiple organ failure, 210 (16%) had an intervention, and 84 (7%) patients died. We found no significant association between obesity and mortality [relative risk (RR) 1.40, 95% confidence interval (CI): 0.89-2.20], necrosis (RR: 1.08, 95% CI: 0.90-1.31) or invasive intervention (RR: 1.10, 95% CI: 0.83-1.47) after adjustment for confounders. However, obesity was independently associated with the development of organ failure (RR: 1.38, 95% CI: 1.11-1.73) and multiple organ failure (RR: 1.81, 95% CI: 1.35-2.42).

CONCLUSION

Obesity is independently associated with the development of organ failure and multiple organ failure in AP. However, there is no association between obesity and mortality, necrosis, and an intervention.

Association Between Body Mass Index and Mortality in Patients Requiring Cardiac Critical Care

BACKGROUND

Data on the association between obesity and mortality in patients who require acute cardiac care are limited, so we investigated the effect of obesity on clinical outcomes in patients admitted to the cardiac intensive care unit (CICU). Methods and Results: We reviewed 2,429 eligible patients admitted to the CICU at Samsung Medical Center between January 2012 and December 2015. After excluding 197 patients with low body mass index (BMI) to adjust for the possibility of frailty, patients were divided into 3 categories: normal BMI (n=822), 18.5-22.9 kg/m²; moderate BMI (n=1,050), 23-27.4 kg/m²; and high BMI (n=360), ≥27.5 kg/m². The primary outcome was 28-day mortality. Overall, 124 (2.6%) of 2,232 patients died during 28-day follow-up after CICU admission. The 28-day mortality was numerically lower in the moderate (4.5%) and high (5.3%) BMI groups than in the normal BMI group (7.1%), but the difference was not statistically significant (P=0.052). After multivariable adjustment, the moderate and high BMI categories were not significant predictors of primary outcome (adjusted hazard ratio [HR] 0.74, 95% CI 0.50-1.09, P=0.127 and adjusted HR 0.80, 95% CI 0.47-1.36, P=0.404, respectively). However, Acute Physiology and Chronic Health Evaluation II scores, liver cirrhosis, malignancy, history of cardiac arrest, and need for organ support treatment were independent predictors of 28-day mortality.

CONCLUSIONS

Obesity was not associated with short-term mortality in patients requiring cardiac critical care.

Association of obesity with morbidity and mortality in critically ill children: a systematic review and meta-analysis of observational studies

Recent studies have suggested that obesity might be protective in specific conditions such as critical illness; however, there are controversial data in critically ill children with obesity. The aim of this study was to investigate the association of obesity with mortality and other outcomes in these patients. We conducted a systematic review of observational studies investigating obesity in critically ill children, published by August 2017 in PubMed and Scopus. After screening documents, 15 articles with 142119 patients were included in the systematic review and meta-analysis. The results were reported with odds ratio (OR) or standard mean difference (SMD). The primary outcome was mortality and the secondary outcomes were length of ICU stay (ICU LOS), length of hospital stay (hospital LOS), and duration of mechanical ventilation (MV). The analysis showed that critically ill children without obesity had lower risk of mortality compared to patients with obesity (OR 0.79, 95% CI 0.64 to 0.97, P = 0.025, I² = 35.2%). Hospital LOS was also significantly lower in children without obesity (pooled SMD -0.12, 95% CI -0.21 to -0.04, P = 0.004, I² = 8.1%). There were no differences in ICU LOS (95% CI -0.19 to 0.01, P = 0.083) and duration of MV (95% CI -0.22 to 0.03, P = 0.136) between critically ill children with and without obesity. In conclusion, the current systematic review and meta-analysis revealed that critically ill children with obesity have higher risk of mortality and length of hospital stay compared to the group without obesity. Further prospective studies are essential to elucidate the role of obesity and underlying mechanisms in predicting outcomes of critically ill children.

The Effect of Age upon the Interrelationship of BMI and Inpatient Health Outcomes

OBJECTIVES

There is growing evidence that the relationship between body mass index (BMI - defined as weight in kilograms divided by height in metres squared) and patient outcomes is age-dependent; specifically, a raised BMI may have a protective effect in older adults. This has been demonstrated clearly in the community setting; less clear is the effect of age on this relationship in the inpatient setting.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

Retrospective analysis of 22,903 electronic records for patients discharged from two large public hospitals in South Australia between January 2015 and September 2018 inclusively. Records were retained if the patient's height and weight had been recorded during the admission, BMI was between 10-99 kg/m2 and it was the patient's first admission during that time. Patients were grouped by BMI (<18.5 kg/m2 ("underweight"), 18.5-24.9 kg/m2 ("normal weight"), 25-29.9 kg/m2 ("overweight"), >30 kg/m2 ("obese")) and age (18-59 years, 60-79 years, > 80 years); for each group we measured the relative stay index (RSI) (actual length of stay divided by predicted length of stay), death in hospital and composite adverse outcome after discharge (unplanned readmission within 30 days and/or death within 30 days).

RESULTS

Underweight patients across all age groups generally experienced significantly poorer outcomes compared to those not underweight. In those aged 18-59 years there were no significant differences in outcomes between the normal weight, overweight and obese groups. In those aged 60-79 years overweight patients had a significantly reduced risk of RSI > 2 compared to those of normal weight (p=0.014), and both overweight and obese patients had a significantly reduced risk of adverse outcome after discharge when compared to those of normal weight (p=0.028 and p=0.009 respectively). In those aged 80 years or older, both overweight and obese patients had a significantly reduced risk of adverse outcome after discharge when compared to those of normal weight (p=0.028 and p=0.013 respectively), and obese patients had a significantly reduced risk of inpatient mortality and RSI >2 when compared to those of normal weight (p=0.027 and p=0.037 respectively).

CONCLUSION

A BMI > 25 kg/m2 in older patients is associated with reduced risk of prolonged admission, inpatient mortality and adverse outcomes following discharge. This adds to growing evidence that age-specific BMI guidelines are required for adults because the healthiest BMI in the older hospital patient is seemingly not in the range 18.5-24.9 kg/m2.

Urinary creatinine excretion is related to short-term and long-term mortality in critically ill patients

PURPOSE

Patients with reduced muscle mass have a worse outcome, but muscle mass is difficult to quantify in the ICU. Urinary creatinine excretion (UCE) reflects muscle mass, but has not been studied in critically ill patients. We evaluated the relation of baseline UCE with short-term and long-term mortality in patients admitted to our ICU.

METHODS

Patients who stayed ≥ 24 h in the ICU with UCE measured within 3 days of admission were included. We excluded patients who developed acute kidney injury stage 3 during the first week of ICU stay. As muscle mass is considerably higher in men than women, we used sex-stratified UCE quintiles. We assessed the relation of UCE with both in-hospital mortality and long-term mortality.

RESULTS

From 37,283 patients, 6151 patients with 11,198 UCE measurements were included. Mean UCE was 54% higher in males compared to females. In-hospital mortality was 17%, while at 5-year follow-up, 1299 (25%) patients had died. After adjustment for age, sex, estimated glomerular filtration rate, body mass index, reason for admission and disease severity, patients in the lowest UCE quintile had an increased in-hospital mortality compared to the patients in the highest UCE quintile (OR 2.56, 95% CI 1.96-3.34). For long-term mortality, the highest risk was also observed for patients in the lowest UCE quintile (HR 2.32, 95% CI 1.89-2.85), independent of confounders.

CONCLUSIONS

In ICU patients without severe renal dysfunction, low urinary creatinine excretion is associated with short-term and long-term mortality, independent of age, sex, renal function and disease characteristics, underscoring the role of muscle mass as risk factor for mortality and UCE as relevant biomarker.