Gender impact on the outcomes of critically ill patients with nosocomial infections*:

The influence of gender on the epidemiology of and outcome from sepsis associated acute kidney injury in ICU: a retrospective propensity-matched cohort study

PURPOSES

The influence of gender on the epidemiology of and outcome from SA-AKI in ICU has not been fully clarified. Our aim is to elucidate these differences.

METHODS

This study included adult patients with sepsis in MIMIC IV (V 2.2), and propensity matching analysis, cox regression and logistic regression were used to analyze gender differences in incidence, mortality and organ support rate.

RESULTS

Of the 24,467 patients included in the cohort, 18,128 were retained after propensity score matching. In the matched cohort, the incidence of SA-AKI in males is higher than that in females (58.6% vs. 56.2%; P = 0.001).males were associated with a higher risk of SA-AKI (OR:1.07(1.01-1.14), P = 0.026;adjusted OR:1.07(1.01-1.14), P < 0.033).In SA-AKI patients, males were associated with a lower risk of ICU mortality(HR:0.803(0.721-0.893), P < 0.001;adjusted HR:0.836(0.746-0.937), P = 0.002) and in-hospital mortality(HR: 0.820(0.748-0.899), P < 0.001;adjusted HR:0.853(0.775-0.938), P = 0.003).there were no statistically significant differences between male and female patients in 1-year all-cause mortality (36.9% vs. 35.8%, P = 0.12), kidney replacement therapy rate (7.8% vs.7.4%, P = 0.547), mechanical ventilation rate 64.8% vs.63.9%, P = 0.369), and usage of vasoactive drugs (55.4% vs. 54.6%, P = 0.418).

CONCLUSIONS

Gender may affect the incidence and outcomes of SA-AKI, further research is needed to fully understand the impact of gender on SA-AKI patients.

Association of Sex and Age with Mortality and Health-Related Quality of Life in Children with Septic Shock: A Secondary Analysis of the Life After Pediatric Sepsis Evaluation

Introduction: Sepsis is more common in males than females, but whether outcomes differ by sex in various pediatric age groups is unclear. The Life After Pediatric Sepsis Evaluation (LAPSE) was a multicenter prospective cohort study that evaluated health-related quality of life (HRQL) in children after community-acquired septic shock. In this secondary analysis, we evaluated whether male children are at increased risk of mortality or long-term decline in HRQL than female children by age group. Methods: Children (1 month-18 years) with community-acquired septic shock were recruited from 12 pediatric intensive care units in the U.S. Data included sex, age group (<1 year, 1-<13 years, 13-18 years), acute illness severity (acute organ dysfunction and inflammation), and longitudinal assessments of HRQL and mortality. Persistent decline in HRQL was defined as a 10% decrease in HRQL comparing baseline to 3 months following admission. Male and female children were stratified by age group and compared to evaluate the difference in the composite outcome of death or persistent decline in HRQL using the Cochran-Mantel-Haenszel test. Results: Of 389 children, 54.2% (n = 211) were male. Overall, 10% (21/211) of males and 12% (22/178) of females died by 3 months (p = 0.454). Among children with follow-up data, 41% (57/138) of males and 44% (48/108) of females died or had persistent decline in HRQL at 3 months (p = 0.636), with no observed difference by sex when stratified by age group. There was no significant difference in acute illness severity between males and females overall or stratified by age group. Conclusions: In this secondary analysis of the LAPSE cohort, HRQL, and mortality were not different between male and female children when stratified by age group. There were no significant differences by sex across multiple measures of illness severity or treatment intensity.

Predictive value of risk factors for prognosis of patients with sepsis in intensive care unit

Sepsis has emerged as a major global public health concern due to its elevated mortality and high cost of care. This study aimed to evaluate the risk factors associated with the mortality of sepsis patients in the Intensive Care Unit (ICU), and to intervene in the early stages of sepsis in order to improve patient outcomes and reduce mortality. From January 1st, 2021 to December 31st, 2021, Longhua Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Huashan Hospital Affiliated to Fudan University, and The Seventh People's Hospital Affiliated to Shanghai University of Traditional Chinese Medicine were designated as sentinel hospitals, and sepsis patients in their respective ICU and Emergency ICU were selected as research subjects, and divided into survivors and non-survivors according to their discharge outcomes. The mortality risk of sepsis patients was subsequently analyzed by logistic regression. A total of 176 patients with sepsis were included, of which 130 (73.9%) were survivors and 46 (26.1%) were non-survivors. Factors identified as having an impact on death among sepsis patients included female [Odds Ratio (OR) = 5.135, 95% confidence interval (CI): 1.709, 15.427, P = .004)], cardiovascular disease (OR = 6.272, 95% CI: 1.828, 21.518, P = .004), cerebrovascular disease (OR = 3.133, 95% CI: 1.093, 8.981, P = .034), pulmonary infections (OR = 6.700, 95% CI: 1.744, 25.748, P = .006), use of vasopressors (OR = 34.085, 95% CI: 10.452, 111.155, P < .001), WBC < 3.5 × 109/L (OR = 9.752, 95% CI: 1.386, 68.620, P = .022), ALT < 7 U/L (OR = 7.672, 95% CI: 1.263, 46.594, P = .027), ALT > 40 U/L (OR = 3.343, 95% CI: 1.097, 10.185, P = .034). Gender, cardiovascular disease, cerebrovascular disease, pulmonary infections, the use of vasopressors, WBC, and ALT are important factors in evaluating the prognostic outcome of sepsis patients in the ICU. This suggests that medical professionals should recognize them expeditiously and implement aggressive treatment tactics to diminish the mortality rate and improve outcomes.

Interactions between Gender and Sepsis—Implications for the Future

Sex and gender dimorphisms are found in a large variety of diseases, including sepsis and septic shock which are more prevalent in men than in women. Animal models show that the host response to pathogens differs in females and males. This difference is partially explained by sex polarization of the intracellular pathways responding to pathogen–cell receptor interactions. Sex hormones seem to be responsible for this polarization, although other factors, such as chromosomal effects, have yet to be investigated. In brief, females are less susceptible to sepsis and seem to recover more effectively than males. Clinical observations produce more nuanced findings, but men consistently have a higher incidence of sepsis, and some reports also claim higher mortality rates. However, variables other than hormonal differences complicate the interaction between sex and sepsis, including comorbidities as well as social and cultural differences between men and women. Conflicting data have also been reported regarding sepsis-attributable mortality rates among pregnant women, compared with non-pregnant females. We believe that unraveling sex differences in the host response to sepsis and its treatment could be the first step in personalized, phenotype-based management of patients with sepsis and septic shock.

Female Patients with Pneumonia on Intensive Care Unit Are under Risk of Fatal Outcome

Background and Objectives: The impact of sex on mortality in patients with pneumonia requiring intensive care unit (ICU) treatment is still a controversial discussion, with studies providing heterogeneous results. The reasons for sex differences are widespread, including hormonal, immunologic and therapeutic approaches. This study's aim was to evaluate sex-related differences in the mortality of ICU patients with pneumonia. Material and Methods: A prospective observational clinical trial was performed at Charité University Hospital in Berlin. Inclusion criteria were a diagnosis of pneumonia and a treatment period of over 24 h on ICU. A total of 436 mainly postoperative patients were included. Results: Out of 436 patients, 166 (38.1%) were female and 270 (61.9%) were male. Significant differences in their SOFA scores on admission, presence of immunosuppression and diagnosed cardiovascular disease were observed. Male patients were administered more types of antibiotics per day (p = 0.028) at significantly higher daily costs (in Euros) per applied anti-infective drug (p = 0.003). Mortalities on ICU were 34 (20.5%) in females and 39 (14.4%) in males (p = 0.113), before correcting for differences in patient characteristics using logistic regression analysis, and afterwards, the female sex showed an increased risk of ICU mortality with an OR of 1.775 (1.029-3.062, p = 0.039). Conclusions: ICU mortality was significantly higher in female patients with pneumonia. The identification of sex-specific differences is important to increase awareness among clinicians and allow resource allocation. The impact of sex on illness severity, sex differences in infectious diseases and the consequences on treatment need to be elucidated in the future.

Sex Differences in Treatment of Adult Intensive Care Patients: A Systematic Review and Meta-Analysis

OBJECTIVES

To evaluate and synthesize the available literature on sex differences in the treatment of adult ICU patients.

DATA SOURCES

MEDLINE and EMBASE.

STUDY SELECTION

Two reviewers independently screened publications to identify observational studies of adult ICU patients that explicitly examined the association between sex and ICU treatment-specifically, mechanical ventilation, renal replacement therapy, and length of stay.

DATA EXTRACTION

We extracted data independently and in duplicate: mean age, illness severity, use of mechanical ventilation and renal replacement therapy, and length of stay in ICU and hospital. We assessed risk of bias using the Newcastle-Ottawa Scale. We used a DerSimonian-Laird random-effects model to calculate pooled odds ratios (ORs) and mean differences between women and men.

DATA SYNTHESIS

We screened 4,098 publications, identifying 21 eligible studies with 545,538 participants (42.7% women). The study populations ranged from 246 to 261,255 participants (median 4,420). Most studies (76.2%) were at high risk of bias in at least one domain, most commonly representativeness or comparability. Women were less likely than men to receive invasive mechanical ventilation (OR, 0.83; 95% CI, 0.77-0.89; I2 = 90.4%) or renal replacement therapy (OR, 0.79; 95% CI, 0.70-0.90; I2 = 76.2%). ICU length of stay was shorter in women than men (mean difference, -0.24 d; 95% CI, -0.37 to -0.12; I2 = 89.9%). These findings persisted in meta-analysis of data adjusted for illness severity and other confounders and also in sensitivity analysis excluding studies at high risk of bias. There was no significant sex difference in duration of mechanical ventilation or hospital length of stay.

CONCLUSIONS

Women were less likely than men to receive mechanical ventilation or renal replacement therapy and had shorter ICU length of stay than men. There is substantial heterogeneity and risk of bias in the literature; however, these findings persisted in sensitivity analyses.

Sex Differences in In-hospital Mortality of Patients With Septic Shock: An Observational Study Based on Data Analysis From a Cover Sheet of Medical Records in Beijing

Background: The goal of our study was to evaluate the association of sex and in-hospital mortality in patients with septic shock in Beijing, China.

Materials and Methods: We analyzed 3,643 adult patients with septic shock from January 1, 2019, to Dec 31, 2019, in all secondary and tertiary hospitals in Beijing. Study data were retrospectively extracted from the Quality Control Center of Beijing Municipal Health Commission.

Results: There were 2,345 (64.37%) male and 1,298 (35.63%) female patients. Compared to male patients, female patients with septic shock had a higher in-hospital mortality rate (55.54 vs. 49.29%, p < 0.01). The median length of hospitalization stay for male patients was 22.71 days, while that for female patients was 19.72 days (p > 0.01). Male patients had a higher prevalence of pulmonary infection (68.8 vs. 31.2%, p < 0.01). The B values of sex in univariate and multivariate logistic regression were −0.251 and −0.312, respectively. Men had a lower likelihood of hospital mortality than women (OR = 0.732, 95% CI = 0.635–0.844, p = 0.000).

Conclusions: Female patients with septic shock had a higher risk of dying in the hospital than male patients.

Invasiveness of Treatment Is Gender Dependent in Intensive Care: Results From a Retrospective Analysis of 26,711 Cases

BACKGROUND

Health care and outcome of critically ill patients are marked by gender-related differences. Several studies have shown that male patients in intensive care units (ICU) more often receive mechanical ventilation, dialysis, pulmonary arterial catheterization (PAC), and central venous catheterization (CVC). We investigated gender-related differences in ICU treatment and mortality.

METHODS

This retrospective, single-center study analyzed adult ICU patients admitted to the University Medical Center Regensburg between January 2010 and December 2017. Illness severity was measured with the Simplified Acute Physiology Score II (SAPS II) at ICU admission. We evaluated the intensity of ICU treatment according to the implementation of tracheostomy and extracorporeal membrane oxygenation (ECMO). We then assessed gender-related differences in the duration of mechanical ventilation and other invasive monitoring (PAC) and treatment methods (CVC, endotracheal intubation rate, and dialysis). ICU treatment and mortality data were obtained from an electronic data capture system. After adjusting for age, reason for hospitalization, and SAPS II score, we assessed the influence of gender on the intensity of ICU treatment using multivariable logistic regression. Odds ratios (OR) for the logistic regression models and incidence rate ratios (IRR) for the negative binomial regression models were calculated as effect estimates together with the corresponding 95% confidence intervals (95% CI). A P value of <.05 was considered significant.

RESULTS

The study analyzed 26,711 ICU patients (64.8% men). The ICU mortality rate was 8.8%. Illness severity, ICU, and hospital mortality did not differ by gender. Women were older than men (62.6 vs 61.3 years; P < .001) at ICU admission. After multivariable adjustment, men were more likely to undergo tracheostomy (OR = 1.39 [1.26-1.54]), ECMO (OR = 1.37 [1.02-1.83]), dialysis (OR = 1.29 [1.18-1.41]), and PAC insertion (OR = 1.81 [1.40-2.33]) and had a longer duration of mechanical ventilation than women (IRR = 1.07 [1.02-1.12]). The frequency of endotracheal intubation (OR = 1.04 [0.98-1.11]) and placement of CVC (OR = 1.05 [0.98-1.11]) showed no gender-specific differences. Of ICU nonsurvivors, men were more likely to undergo tracheostomy (20.1% vs 15.3%; P = .004) and dialysis (54% vs 46.4%; P < .001) than women and had a longer duration of mechanical ventilation (6.3 vs 5.4 days; P = .015).

CONCLUSIONS

After adjustment for severity of disease and outcome, ICU treatment differs between men and women. Men were more likely than women to undergo tracheostomy and ECMO.

Sex differences in illness severity and mortality among adult intensive care patients: A systematic review and meta-analysis

PURPOSE

To investigate the association between sex and illness severity and mortality of ICU patients.

METHODS

We performed systematic searches of MEDLINE and EMBASE for observational studies of adult ICU patients that explicitly examined the association between sex and illness severity or mortality. We used a random effects model to calculate standardised mean differences in illness severity scores and pooled odds ratios for mortality of women compared to men.

RESULTS

We identified 21 studies with 505,138 participants in total (43.1% women). There was substantial heterogeneity among studies. Only two studies were at low risk of bias overall. At ICU admission, there was a pattern of higher illness severity scores among women (standardised mean difference 0.04, 95% CI -0.01-0.09). Women had higher risk-adjusted mortality than men at ICU discharge (OR 1.25 95% CI 1.03-1.50) and 1 year (OR 1.08, 95% CI 1.02-1.13), however this finding was not robust to sensitivity analysis.

CONCLUSIONS

Women tend to have higher illness severity scores at ICU admission. Women also appear to have higher risk-adjusted mortality than men at ICU discharge and at 1 year. Given the heterogeneity and risk of bias in the existing literature, additional studies are needed to confirm or refute these findings.

Physical Function Trajectories in Survivors of Acute Respiratory Failure

RATIONALE

Survivorship from critical illness has improved; however, factors mediating the functional recovery of persons experiencing a critical illness remain incompletely understood.

OBJECTIVES

To identify groups of acute respiratory failure (ARF) survivors with similar patterns of physical function recovery after discharge and to determine the characteristics associated with group membership in each physical function trajectory group.

METHODS

We performed a secondary analysis of a randomized controlled trial, using group-based trajectory modeling to identify distinct subgroups of patients with similar physical function recovery patterns after ARF. Chi-square tests and one-way analysis of variance were used to determine which variables were associated with trajectory membership. A multinomial logistic regression analysis was performed to identify variables jointly associated with trajectory group membership.

RESULTS

A total of 260 patients enrolled in a trial evaluating standardized rehabilitation therapy in patients with ARF and discharged alive (NCT00976833) were included in this analysis. Physical function was quantified using the Short Physical Performance Battery at hospital discharge and 2, 4, and 6 months after enrollment. Latent class analysis of the Short Physical Performance Battery scores identified four trajectory groups. These groups differ in both the degree and rate of physical function recovery. A multinomial logistic regression analysis was performed using covariates that have been previously identified in the literature as influencing recovery after critical illness. By multinomial logistic regression, age (P < 0.001), female sex (P = 0.001), intensive care unit (ICU) length of stay (LOS) (P = 0.003), and continuous intravenous sedation days (P = 0.004) were the variables that jointly influenced trajectory group membership. Participants in the trajectory demonstrating most rapid and complete functional recovery consisted of younger females with fewer continuous sedation days and a shorter LOS. The participant trajectory that failed to functionally recover consisted of older patients with greater sedation time and the longest LOS.

CONCLUSIONS

We identified distinct trajectories of physical function recovery after critical illness. Age, sex, continuous sedation time, and ICU length of stay impact the trajectory of functional recovery after critical illness. Further examination of these groups may assist in clinical trial design to tailor interventions to specific subgroups.

Risk factors for mortality among patients with Pseudomonas aeruginosa bacteraemia: a retrospective multicentre study

This study aimed to evaluate risk factors for 30-day mortality among hospitalised patients with Pseudomonas aeruginosa bacteraemia, a highly fatal condition. A retrospective study was conducted between 1 January 2009 and 31 October 2015 in 25 centres (9 countries) including 2396 patients. Univariable and multivariable analyses of risk factors were conducted for the entire cohort and for patients surviving ≥48 h. A propensity score for predictors of appropriate empirical therapy was introduced into the analysis. Of the 2396 patients, 636 (26.5%) died within 30 days. Significant predictors (odds ratio and 95% confidence interval) of mortality in the multivariable analysis included patient-related factors: age (1.02, 1.01-1.03); female sex (1.34, 1.03-1.77); bedridden functional capacity (1.99, 1.24-3.21); recent hospitalisation (1.43, 1.07-1.92); concomitant corticosteroids (1.33, 1.02-1.73); and Charlson comorbidity index (1.05, 1.01-1.93). Infection-related factors were multidrug-resistant Pseudomonas (1.52, 1.15-2.1), non-urinary source (2.44, 1.54-3.85) and Sequential Organ Failure Assessment (SOFA) score (1.27, 1.18-1.36). Inappropriate empirical therapy was not associated with increased mortality (0.81, 0.49-1.33). Among 2135 patients surviving ≥48 h, hospital-acquired infection (1.59, 1.21-2.09), baseline endotracheal tube (1.63, 1.13-2.36) and ICU admission (1.53, 1.02-2.28) were additional risk factors. Risk factors for mortality among patients with P. aeruginosa were mostly irreversible. Early appropriate empirical therapy was not associated with reduced mortality. Further research should be conducted to explore subgroups that may not benefit from broad-spectrum antipseudomonal empirical therapy. Efforts should focus on prevention of infection, mainly hospital-acquired infection and multidrug-resistant pseudomonal infection.

Sex-based differences in ED management of critically ill patients with sepsis: a nationwide cohort study

Purpose

To compare management and outcomes for critically ill women and men with sepsis in the emergency medical services (EMS), the emergency department (ED) and the ICU.

Methods

We used two prospectively compiled Swedish national quality registers, the National Quality Sepsis Registry and the Swedish Intensive Care Registry to identify a nationwide cohort of 2720 adults admitted to an ICU within 24 h of arrival to any of 32 EDs, with a diagnosis of severe sepsis or septic shock between 2008 and 2015.

Results

Patients were 44.5% female. In the EMS, a higher fraction of men had all vital signs recorded—54.4 vs 49.9% (p = 0.02) and received IV fluids and oxygen—40.0 vs 34.8% (p = 0.02). In the ED, men had completed 1-h sepsis bundles in 41.5% of cases compared to 30.0% in women (p < 0.001), and shorter time to antibiotics—65 (IQR 30–136) vs 87 min (IQR 39–172) (p = 0.0001). There was no significant difference between men and women regarding ICU nursing workload, mechanical ventilation or ICU length of stay. In severity-adjusted multivariable analysis, OR for women achieving a completed sepsis bundle, compared to men was 0.64 (CI 0.51–0.81). Thirty-day mortality was 25.0% for women and 23.1% for men (p = 0.24). Adjusted OR for female death was 1.28 (CI 1.00–1.64), but the increased mortality was not mediated by differential bundle completion.

Conclusions

Women and men with severe sepsis or septic shock received differential care in the ED, but this did not explain higher odds of death in women.

Electronic supplementary material

The online version of this article (10.1007/s00134-019-05910-9) contains supplementary material, which is available to authorized users.

Clinical and Demographic Parameters of Patients Treated Using a Sepsis Protocol

PURPOSE

The purpose of this study was to investigate potential differences by sex in the demographic and clinical characteristics of patients treated utilizing a sepsis electronic bundle order set. Risk factors for in-hospital mortality were also assessed.

METHODS

Data on patients in whom the sepsis order set was initiated in the emergency department over a 16-month period were entered into the hospital database. Data were analyzed for differences by sex in demographic and clinical factors, treatment modalities, and in-hospital mortality. The Bonferroni correction was applied to account for multiple comparisons; α was set at 0.006 for sex differences.

FINDINGS

A total of 2204 patients were included. Male and female cohorts were similar with regard to a variety of demographic and clinical factors, including age, Emergency Severity Index (ESI) levels 1 and 2, time to disposition, appropriateness of antibiotics, and total fluids given by weight. The ESI is an assessment score ranging from 1 to 5 (1 is emergent). There were modest differences in the source of infection (genitourinary was 4% more common in women; P = 0.03) and mode of arrival (men were 4% more likely to arrive by ambulance; P = 0.03). These differences did not achieve our predefined α of 0.006 when the Bonferroni correction was applied. Factors associated with in-hospital mortality were advanced age, arrival by ambulance, and an ESI level of 1 or 2 (all, P < 0.01).

IMPLICATIONS

Women were more likely to have a genitourinary cause of sepsis and less likely to arrive by ambulance. Risk factors of in-hospital mortality were older age, arrival by ambulance, and an ESI level of 1 or 2, but not sex.

Sex differences of inflammation in target organs, induced by intraperitoneal injection of lipopolysaccharide, depend on its dose

Purpose

The aim of our research was to study sex differences and the severity of inflammatory changes in target organs and the peculiarities of immunological disorders when low and high doses of lipopolysaccharide (LPS) were administered to rats.

Methods

Male and female 2- to 3-month-old Wistar rats (200–250 g) were injected intraperitoneally with Escherichia coli LPS in one of two doses: 1.5 or 15 mg/kg. In a day after the LPS injection, we studied endotoxin, corticosterone, sex steroids, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) activity levels in the serum; morphological disorders in the lung, liver, thymus, and spleen; ex vivo production of IL-2, IL-4, tumor necrosis factor (TNF), and interferon γ (IFNγ) by splenic cells activated by ConA; and relative amount of T- and B-lymphocytes in the peripheral blood.

Results

After the injection of low-dose LPS, the serum endotoxin level increased only in males and was combined with a more pronounced inflammatory response in the lungs and thymus and an increase in ALT and AST activity levels without any changes in corticosterone level. After the injection of high-dose LPS, the inflammatory and pathological changes in the target organs manifested as severe endotoxemia and sex differences of pathological changes in the lungs and liver were not revealed. The level of production of IL-2, IL-4, IFNγ, and TNF by splenic cells and the number of T-lymphocytes, including cytotoxic cells, in the peripheral blood, decreased in males, which is an evidence of a pronounced suppression of the immune response.

Conclusion

We have shown that the morphofunctional changes in the organs of the immune system in females and males, as well as the intensity of the sex differences of inflammation, depend on the severity of systemic inflammatory response, induced by different doses of LPS.

Sphingosine-1-phosphate Receptor 2 Signaling Promotes Caspase-11–dependent Macrophage Pyroptosis and Worsens Escherichia coli Sepsis Outcome

What We Already Know about This Topic

What This Article Tells Us That Is New

Background

Pyroptosis, a type of proinflammatory programmed cell death, drives cytokine storm. Caspase-11–dependent macrophage pyroptosis contributes to mortality during sepsis. Sphingosine-1-phosphate receptor 2 (S1PR2) signaling can amplify interleukin-1β secretion in endotoxin-induced inflammation. Here, we hypothesized that S1PR2 signaling increases caspase-11–dependent macrophage pyroptosis and worsens Gram-negative sepsis outcome.

Methods

A Gram-negative sepsis model was induced through intraperitoneal injection of Escherichia coli. Primary peritoneal macrophages isolated from wild-type, S1pr2-deficient (S1pr2-/-), or nucleotide-binding oligomerization domain-like receptor protein-3–deficient mice were treated with E. coli. Caspase-11 activation, macrophage pyroptosis, and Ras homolog gene family, member A-guanosine triphosphate levels were assessed in those cells. Additionally, monocyte caspase-4 (an analog of caspase-11) expression and its correlation with S1PR2 expression were determined in patients with Gram-negative sepsis (n = 11).

Results

Genetic deficiency of S1PR2 significantly improved survival rate (2/10 [20%] in wild-type vs. 7/10 [70%] in S1pr2-/-, P = 0.004) and decreased peritoneal macrophage pyroptosis (pyroptosis rate: 35 ± 3% in wild-type vs. 10 ± 3% in S1pr2-/-, P &lt; 0.001). Decreased caspase-11 activation in S1PR2 deficiency cells contributed to the reduced macrophage pyroptosis. In addition, RhoA inhibitor abrogated the amplified caspase-11 activation in wild-type or S1PR2-overexpressing cells. In patients with Gram-negative sepsis, caspase-4 increased significantly in monocytes compared to nonseptic controls and was positively correlated with S1PR2 (r = 0.636, P = 0.035).

Conclusions

S1PR2 deficiency decreased macrophage pyroptosis and improved survival in E. coli sepsis. These beneficial effects were attributed to the decreased caspase-11 activation of S1PR2-deficient macrophages. S1PR2 and caspase-11 may be promising new targets for treatment of sepsis.

Serum Estradiol Level at Intensive Care Unit Admission and Mortality in Critically Ill Patients

Context:

It has been observed that sex hormones may play a role in inflammatory processes and mortality of critically ill patients.

Aims:

The aim was evaluated the relationship between serum estradiol level at Intensive Care Unit (ICU) admission and mortality of critically ill patients.

Settings and Design:

This study was a prospective cohort conducted in one mixed ICU.

Subjects and Methods:

In heterogeneous group of critically ill patients admitted to the ICU, we measured serum estradiol at admission time.

Statistical Analysis Used:

The discrimination to predict mortality of serum estradiol level was assessed by the receiver-operating curve (ROC) curve and its association with mortality by logistic regression analysis.

Results:

We included 131 patients, 57.3% of which were male. The serum estradiol level measured at ICU admission was significantly higher in nonsurvivors than in survivors: 116 versus 67.2 pg/mL, respectively (P < 0.0001). The area under the ROC of serum estradiol level to predict mortality was 0.74 (P < 0.0001). Serum estradiol level ≥97.9 pg/mL had sensitivity of 60%, specificity of 90%, positive predictive value of 64%, negative predictive value of 88%, positive likelihood ratio of 6, and negative likelihood ratio of 0.44, for predicting mortality. In multivariate analysis, it had relative risk of 6.47 (P = 0.002) for ICU mortality.

Conclusions:

The serum estradiol level is elevated in critically ill patients, regardless of gender, especially in those who die. It has good discriminative capacity to predict mortality, and it is an independent risk factor for death in this group of patients.

Association of Gender With Outcome and Host Response in Critically Ill Sepsis Patients

OBJECTIVE

To determine the association of gender with the presentation, outcome, and host response in critically ill patients with sepsis.

DESIGN AND SETTING

A prospective observational cohort study in the ICU of two tertiary hospitals between January 2011 and January 2014.

PATIENTS

All consecutive critically ill patients admitted with sepsis, involving 1,815 admissions (1,533 patients).

INTERVENTIONS

The host response was evaluated on ICU admission by measuring 19 plasma biomarkers reflecting organ systems implicated in sepsis pathogenesis (1,205 admissions) and by applying genome-wide blood gene expression profiling (582 admissions).

MEASUREMENTS AND MAIN RESULTS

Sepsis patients admitted to the ICU were more frequently males (61.0%; p < 0.0001 vs females). Baseline characteristics were not different between genders. Urosepsis was more common in females; endocarditis and mediastinitis in men. Disease severity was similar throughout ICU stay. Mortality was similar up to 1 year after ICU admission, and gender was not associated with 90-day mortality in multivariate analyses in a variety of subgroups. Although plasma proteome analyses (including systemic inflammatory and cytokine responses, and activation of coagulation) were largely similar between genders, females showed enhanced endothelial cell activation; this difference was virtually absent in patients more than 55 years old. More than 80% of the leukocyte blood gene expression response was similar in male and female patients.

CONCLUSIONS

The host response and outcome in male and female sepsis patients requiring ICU admission are largely similar.

Smoking, Gender, and Overweight Are Important Influencing Factors on Monocytic HLA-DR before and after Major Cancer Surgery

Background

Monocytic human leukocyte antigen D related (mHLA-DR) is essential for antigen-presentation. Downregulation of mHLA-DR emerged as a general biomarker of impaired immunity seen in patients with sepsis and pneumonia and after major surgery. Influencing factors of mHLA-DR such as age, overweight, diabetes, smoking, and gender remain unclear.

Methods

We analyzed 20 patients after esophageal or pancreatic resection of a prospective, randomized, placebo-controlled, double-blind trial (placebo group). mHLA-DR was determined from day of surgery (od) until postoperative day (pod) 5. Statistical analyses were performed using multivariate generalized estimating equation analyses (GEE), nonparametric multivariate analysis of longitudinal data, and univariate post hoc nonparametric Mann–Whitney tests.

Results

In GEE, smoking and gender were confirmed as significant influencing factors over time. Univariate analyses of mHLA-DR between smokers and nonsmokers showed lower preoperative levels (p = 0.010) and a trend towards lower levels on pod5 (p = 0.056) in smokers. Lower mHLA-DR was seen in men on pod3 (p = 0.038) and on pod5 (p = 0.026). Overweight patients (BMI > 25 kg/m²) had lower levels of mHLA-DR on pod3 (p = 0.039) and pod4 (p = 0.047).

Conclusion

Smoking is an important influencing factor on pre- and postoperative immune function while postoperative immune function was influenced by gender and overweight. Clinical trial registered with ISRCTN27114642.

Bioavailable estradiol concentrations are elevated and predict mortality in septic patients: a prospective cohort study

BACKGROUND

Experimental studies demonstrate beneficial immunological and hemodynamic effects of estradiol in animal models of sepsis. This raises the question whether estradiol contributes to sex differences in the incidence and outcomes of sepsis in humans. Yet, total estradiol levels are elevated in sepsis patients, particularly nonsurvivors. Bioavailable estradiol concentrations have not previously been reported in septic patients. The bioavailable estradiol concentration accounts for aberrations in estradiol carrier protein concentrations that could produce discrepancies between total and bioavailable estradiol levels. We hypothesized that bioavailable estradiol levels are low in septic patients and sepsis nonsurvivors.

METHODS

We conducted a combined case-control and prospective cohort study. Venous blood samples were obtained from 131 critically ill septic patients in the medical and surgical intensive care units at the University of Rochester Medical Center and 51 control subjects without acute illness. Serum bioavailable estradiol concentrations were calculated using measurements of total estradiol, sex hormone-binding globulin, and albumin. Comparisons were made between patients with severe sepsis and control subjects and between hospital survivors and nonsurvivors. Multivariable logistic regression analysis was also performed.

RESULTS

Bioavailable estradiol concentrations were significantly higher in sepsis patients than in control subjects (211 [78-675] pM vs. 100 [78-142] pM, p < 0.01) and in sepsis nonsurvivors than in survivors (312 [164-918] pM vs. 167 [70-566] pM, p = 0.04). After adjustment for age and comorbidities, patients with bioavailable estradiol levels above the median value had significantly higher risk of hospital mortality (OR 4.27, 95 % CI 1.65-11.06, p = 0.003). Bioavailable estradiol levels were directly correlated with severity of illness and did not differ between men and women.

CONCLUSIONS

Contrary to our hypothesis, bioavailable estradiol levels were elevated in sepsis patients, particularly nonsurvivors, and were independently associated with mortality. Whether estradiol's effects are harmful, beneficial, or neutral in septic patients remains unknown, but our findings raise caution about estradiol's therapeutic potential in this setting. Our findings do not provide an explanation for sex-based differences in sepsis incidence and outcomes.

Risk factors for mortality in patients admitted to intensive care units with pneumonia

Background

Despite the high mortality in patients with pneumonia admitted to an ICU, data on risk factors for death remain limited.

Methods

In this secondary analysis of PROTECT (Prophylaxis for Thromboembolism in Critical Care Trial), we focused on the patients admitted to ICU with a primary diagnosis of pneumonia. The primary outcome for this study was 90-day hospital mortality and the secondary outcome was 90-day ICU mortality. Cox regression model was conducted to examine the relationship between baseline and time-dependent variables and hospital and ICU mortality.

Results

Six hundred sixty seven patients admitted with pneumonia (43.8 % females) were included in our analysis, with a mean age of 60.7 years and mean APACHE II score of 21.3. During follow-up, 111 patients (16.6 %) died in ICU and in total, 149 (22.3 %) died in hospital. Multivariable analysis demonstrated significant independent risk factors for hospital mortality including male sex (hazard ratio (HR) = 1.5, 95 % confidence interval (CI): 1.1 - 2.2, p-value = 0.021), higher APACHE II score (HR = 1.2, 95 % CI: 1.1 - 1.4, p-value < 0.001 for per-5 point increase), chronic heart failure (HR = 2.9, 95 % CI: 1.6 - 5.4, p-value = 0.001), and dialysis (time-dependent effect: HR = 2.7, 95 % CI: 1.3 - 5.7, p-value = 0.008). Higher APACHE II score (HR = 1.2, 95 % CI: 1.1 - 1.4, p-value = 0.002 for per-5 point increase) and chronic heart failure (HR = 2.6, 95 % CI: 1.3 – 5.0, p-value = 0.004) were significantly related to risk of death in the ICU.

Conclusion

In this study using data from a multicenter thromboprophylaxis trial, we found that male sex, higher APACHE II score on admission, chronic heart failure, and dialysis were independently associated with risk of hospital mortality in patients admitted to ICU with pneumonia. While high illness severity score, presence of a serious comorbidity (heart failure) and need for an advanced life support (dialysis) are not unexpected risk factors of mortality, male sex might necessitate further exploration. More studies are warranted to clarify the effect of these risk factors on survival in critically ill patients admitted to ICU with pneumonia.

Trial registration

ClinicalTrials.gov Identifier: NCT00182143.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0397-5) contains supplementary material, which is available to authorized users.

Body mass index, age and in-hospital mortality: The NutritionDay multinational survey

BACKGROUND & AIMS

Several large and long-term prospective studies have assessed the association of body-mass index (BMI) next to age with the risk of death in the general population, but few have examined the association with in-hospital mortality. We investigated the association between BMI, age and in-hospital mortality.

METHODS

We used data collected during 9 consecutive one-day/year surveys (NutritionDay in hospital 2006-2014) conducted in non-critically ill adult patients from 2,183 hospitals across 51 nations from 4 continents. We examined the association of BMI and age with the risk of in-hospital (30-day) death using logistic regression analysis adjusted for multiple confounders.

RESULTS

Crude mortality rates were 3.6% (95%CI, 3.5-3.7) and 2.1% (95%CI, 2.0-2.3) in the overall cohort (N = 97,344) and in those assessed within 72 hours since admission (N = 32,363), respectively. BMI and age were independently associated with the risk of death (no interaction observed), which decreased with BMI and increased with age. In the overall cohort, compared to normal weight status (BMI 18.5-24.9 kg/m²), death odds ratios for underweight (BMI < 18.5), overweight (BMI 25.0-29.9) and obesity (BMI ≥30) were 1.35 (95%CI, 1.20-1.53), 0.87 (95%CI, 0.77-0.97) and 0.73 (95%CI, 0.62-0.86), respectively. In patients assessed within 72 hours since admission, the associations were comparable: for underweight, 1.48 (95%CI, 1.11-1.96); for overweight, 0.80 (95%CI, 0.65-0.97); for obesity, 0.75 (95%CI, 0.58-0.96).

CONCLUSION

In adult hospitalized patients BMI and age are independent predictors of in-hospital mortality. Low body weight is confirmed being a risk factor for death as in the general population, while overweight and obesity appear protective conditions. In the hospital setting, the use of normal weight status as reference low-risk category could also be challenged.

Risk factors for and prediction of mortality in critically ill medical-surgical patients receiving heparin thromboprophylaxis

Background

Previous studies have suggested that prediction models for mortality should be adjusted for additional risk factors beyond the Acute Physiology and Chronic Health Evaluation (APACHE) score. Our objective was to identify risk factors independent of APACHE II score and construct a prediction model to improve the predictive accuracy for hospital and intensive care unit (ICU) mortality.

Methods

We used data from a multicenter randomized controlled trial (PROTECT, Prophylaxis for Thromboembolism in Critical Care Trial) to build a new prediction model for hospital and ICU mortality. Our primary outcome was all-cause 60-day hospital mortality, and the secondary outcome was all-cause 60-day ICU mortality.

Results

We included 3746 critically ill non-trauma medical–surgical patients receiving heparin thromboprophylaxis (43.3 % females) in this study. The new model predicting 60-day hospital mortality incorporated APACHE II score (main effect: hazard ratio (HR) = 0.97 for per-point increase), body mass index (BMI) (main effect: HR = 0.92 for per-point increase), medical admission versus surgical (HR = 1.67), use of inotropes or vasopressors (HR = 1.34), acetylsalicylic acid or clopidogrel (HR = 1.27) and the interaction term between APACHE II score and BMI (HR = 1.002 for per-point increase). This model had a good fit to the data and was well calibrated and internally validated. However, the discriminative ability of the prediction model was unsatisfactory (C index < 0.65). Sensitivity analyses supported the robustness of these findings. Similar results were observed in the new prediction model for 60-day ICU mortality which included APACHE II score, BMI, medical admission and invasive mechanical ventilation.

Conclusion

Compared with the APACHE II score alone, the new prediction model increases data collection, is more complex but does not substantially improve discriminative ability.

Trial registration: ClinicalTrials.gov Identifier: NCT00182143

Effects of Different Blood Glucose Levels on Critically Ill Patients in an Intensive Care Unit

AIMS

We explore the infection incidence and possible prognostic outcome relevance for patients with different blood glucose levels in an intensive care unit (ICU).

METHODS

A total of 98 cases were enrolled and divided into three groups based on average fasting blood glucose levels (group A: ≤ 6.1 mmol/l; group B: 6.1-10 mmol/l; group C: ≥ 10 mmol/l).

RESULTS

There were no statistical differences in the time to ICU admission, the indwelling durations of gastric tubes, urinary or deep vein catheters, tracheal intubations and tracheotomies, or the length of ventilator use (all p > 0.05). No evident difference in the multiple organ dysfunction syndrome rate was found between the three groups (p = 0.226). The infection and mortality rates between the groups showed significant differences (all p < 0.05). Furthermore, the difference of respiratory system infections was statistically significant among the three groups (p = 0.008), yet no such statistical difference was observed among groups regarding nonrespiratory system infections (p = 0.227).

CONCLUSIONS

Critically ill patients with a high blood glucose level were positively correlated with a relatively high APACHE II score and more serious degree of disease, as well as a higher incidence of respiratory infection during their ICU stay than those with lower blood glucose levels (<10 mmol/l).

The association between colonization with carbapenemase-producing enterobacteriaceae and overall ICU mortality: an observational cohort study

OBJECTIVES

Infections caused by carbapenemase-producing Enterobacteriaceae are increasing worldwide, especially in ICUs, and have been associated with high mortality rates. However, unequivocally demonstrating causality of such infections to death is difficult in critically ill patients because of potential confounding and competing events. Here, we quantified the effects of carbapenemase-producing Enterobacteriaceae carriage on patient outcome in two Greek ICUs with carbapenemase-producing Enterobacteriaceae endemicity.

DESIGN

Observational cohort study.

SETTING

Two ICUs with carbapenemase-producing Enterobacteriaceae endemicity.

PATIENTS

Patients admitted to the ICU with an expected length of ICU stay of at least 3 days were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Carbapenemase-producing Enterobacteriaceae colonization was established through screening in perineum swabs obtained at admission and twice weekly and inoculated on chromogenic plates. Detection of carbapenemases was performed phenotypically, with confirmation by polymerase chain reaction. Risk factors for ICU mortality were evaluated using cause-specific hazard ratios and subdistribution hazard ratios, with carbapenemase-producing Enterobacteriaceae colonization as time-varying covariate. One thousand seven patients were included, 36 (3.6%) were colonized at admission, and 96 (9.5%) acquired carbapenemase-producing Enterobacteriaceae colonization during ICU stay, and 301 (29.9%) died in ICU. Of 132 carbapenemase-producing Enterobacteriaceae isolates, 125 (94.7%) were Klebsiella pneumoniae and 74 harbored K. pneumoniae carbapenemase (56.1%), 54 metallo-β-lactamase (40.9%), and four both (3.0%). Carbapenemase-producing Enterobacteriaceae colonization was associated with a statistically significant increase of the subdistribution hazard ratio for ICU mortality (subdistribution hazard ratio=1.79; 95% CI, 1.31-2.43), not explained by an increased daily hazard of dying (cause-specific hazard ratio for death=1.02; 95% CI, 0.74-1.41), but by an increased length of stay (cause-specific hazard ratio for discharge alive=0.73; 95% CI, 0.51-0.94). Other risk factors in the subdistribution hazard model were Acute Physiology and Chronic Health Evaluation II score (subdistribution hazard ratio=1.13; 95% CI, 1.11-1.15), female gender (subdistribution hazard ratio=1.29; 95% CI, 1.02-1.62), presence of solid tumor (subdistribution hazard ratio=1.54; 95% CI, 1.15-2.06), hematopoietic malignancy (subdistribution hazard ratio=1.61; 95% CI, 1.04-2.51), and immunodeficiency (subdistribution hazard ratio=1.59; 95% CI, 1.11-2.27).

CONCLUSIONS

Patients colonized with carbapenemase-producing Enterobacteriaceae have on average a 1.79 times higher hazard of dying in ICU than noncolonized patients, primarily because of an increased length of stay.

The association between colonization with carbapenemase-producing enterobacteriaceae and overall ICU mortality: an observational cohort study

OBJECTIVES

Infections caused by carbapenemase-producing Enterobacteriaceae are increasing worldwide, especially in ICUs, and have been associated with high mortality rates. However, unequivocally demonstrating causality of such infections to death is difficult in critically ill patients because of potential confounding and competing events. Here, we quantified the effects of carbapenemase-producing Enterobacteriaceae carriage on patient outcome in two Greek ICUs with carbapenemase-producing Enterobacteriaceae endemicity.

DESIGN

Observational cohort study.

SETTING

Two ICUs with carbapenemase-producing Enterobacteriaceae endemicity.

PATIENTS

Patients admitted to the ICU with an expected length of ICU stay of at least 3 days were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Carbapenemase-producing Enterobacteriaceae colonization was established through screening in perineum swabs obtained at admission and twice weekly and inoculated on chromogenic plates. Detection of carbapenemases was performed phenotypically, with confirmation by polymerase chain reaction. Risk factors for ICU mortality were evaluated using cause-specific hazard ratios and subdistribution hazard ratios, with carbapenemase-producing Enterobacteriaceae colonization as time-varying covariate. One thousand seven patients were included, 36 (3.6%) were colonized at admission, and 96 (9.5%) acquired carbapenemase-producing Enterobacteriaceae colonization during ICU stay, and 301 (29.9%) died in ICU. Of 132 carbapenemase-producing Enterobacteriaceae isolates, 125 (94.7%) were Klebsiella pneumoniae and 74 harbored K. pneumoniae carbapenemase (56.1%), 54 metallo-β-lactamase (40.9%), and four both (3.0%). Carbapenemase-producing Enterobacteriaceae colonization was associated with a statistically significant increase of the subdistribution hazard ratio for ICU mortality (subdistribution hazard ratio=1.79; 95% CI, 1.31-2.43), not explained by an increased daily hazard of dying (cause-specific hazard ratio for death=1.02; 95% CI, 0.74-1.41), but by an increased length of stay (cause-specific hazard ratio for discharge alive=0.73; 95% CI, 0.51-0.94). Other risk factors in the subdistribution hazard model were Acute Physiology and Chronic Health Evaluation II score (subdistribution hazard ratio=1.13; 95% CI, 1.11-1.15), female gender (subdistribution hazard ratio=1.29; 95% CI, 1.02-1.62), presence of solid tumor (subdistribution hazard ratio=1.54; 95% CI, 1.15-2.06), hematopoietic malignancy (subdistribution hazard ratio=1.61; 95% CI, 1.04-2.51), and immunodeficiency (subdistribution hazard ratio=1.59; 95% CI, 1.11-2.27).

CONCLUSIONS

Patients colonized with carbapenemase-producing Enterobacteriaceae have on average a 1.79 times higher hazard of dying in ICU than noncolonized patients, primarily because of an increased length of stay.

Mechanical ventilation and mobilization: comparison between genders

[Purpose] To investigate the impact of gender on mobilization and mechanical ventilation in hospitalized patients in an intensive care unit. [Subjects and Methods] A retrospective cross-sectional study was conducted of the medical records of 105 patients admitted to a general intensive care unit. The length of mechanical ventilation, length of intensive care unit stay, weaning, time to sitting out of bed, time to performing active exercises, and withdrawal of sedation exercises were evaluated in addition to the characteristics of individuals, reasons for admission and risk scores. [Results] Women had significantly lower values APACHE II scores, duration of mechanical ventilation, time to withdrawal of sedation and time to onset of active exercises. [Conclusion] Women have a better functional response when admitted to the intensive care unit, spending less time ventilated and performing active exercises earlier.

Significant sex-based outcome differences in severely injured Chinese trauma patients

A body of experimental evidence suggests that the female sex is associated with a lower risk of mortality after trauma-hemorrhage. However, controversy remains regarding the mechanism responsible for these differences and if basic science findings correspond to clinical differences. Racial disparities in trauma outcomes have also been increasingly described. Until now, research on the association between sex and trauma patient outcomes mainly focused on patients in Europe and the United States. Our research attempted to determine whether the female sex is associated with a survival advantage among severely injured Chinese trauma patients. A retrospective analysis of data derived from the Emergency Intensive Care Unit of the Shanghai Sixth People';s Hospital Acute Trauma Center during 2010 to 2013 was performed to characterize differences in sex-based outcomes after severe blunt trauma. The patient study cohort (858 Asian subjects) was then stratified by age and injury severity (using the Injury Severity Score [ISS]). Crude and adjusted odds ratios (ORs) were calculated to evaluate the association between sex and nosocomial infection rate and hospitalized mortality, both overall and by age and ISS category subgroups. Among all trauma patients, females had a significantly lower risk of in-hospital mortality compared with males (OR, 0.41; 95% confidence interval [95% CI], 0.20 - 0.85). This difference was most apparent for patients younger than 50 years (OR, 0.31; 95% CI, 0.12 - 0.82) and the group with ISS scores of 25 or higher (OR, 0.39; 95% CI, 0.17 - 0.91). No differences in the development of nosocomial infections between sexes were seen among the overall patient group and subgroups. This study revealed a statistically significant association between sex and mortality among severe blunt trauma patients, particularly those patients younger than 50 years and with ISSs of 25 or higher. Women had significantly lower mortality than men after severe blunt trauma. These results highlight the important role of sex hormones and sex-based outcome differences after severe traumatic injury in the Chinese population.

Gender differences in randomised, controlled trials in intensive care units

There is a male dominance among patients in intensive care units (ICUs). Potentially, this will increase the risk of a skewed male/female distribution in randomised, controlled trials (RCTs). We have evaluated if this has in fact happened when randomising and whether the authors have been aware of that. We performed a systematic search on PubMed from 1 January 2011 to 31 May 2012 using the mesh terms 'randomized controlled trial' and 'intensive care unit'. Twenty-five RCTs with a total of 12,788 patients met the inclusion criteria, with an overall male dominance of 63.6% (P < 0.0001). Eighteen of the 25 papers had an individually statistically significant gender difference in their total trial population. None of the 18 trials with a significant gender difference in their overall trial population had calculated the P-value for this overall difference. In the randomised groups, there was a significant gender difference in five papers. Seventeen had no significant gender difference in the randomised groups, and three papers did not state gender in the randomised groups. This study show that there is a marked male dominance in RCTs conducted in ICUs. We recommend that when planning future RCTs, the authors contemplate if their results can be used indiscriminately among ICU patients if the distribution of males and females is much skewed. It is relevant to determine if ones endpoint can be influenced by gender differences and if there is a risk of gender influence on data, proportional allocation or stratification should be considered.

Sex- and diagnosis-dependent differences in mortality and admission cytokine levels among patients admitted for intensive care

OBJECTIVES

To investigate the role of sex on cytokine expression and mortality in critically ill patients.

DESIGN

A cohort of patients admitted to were enrolled and followed over a 5-year period.

SETTING

Two university-affiliated hospital surgical and trauma ICUs.

PATIENTS

Patients 18 years old and older admitted for at least 48 hours to the surgical or trauma ICU.

INTERVENTIONS

Observation only.

MEASUREMENTS AND MAIN RESULTS

Major outcomes included admission cytokine levels, prevalence of ICU-acquired infection, and mortality during hospitalization conditioned on trauma status and sex. The final cohort included 2,291 patients (1,407 trauma and 884 nontrauma). The prevalence of ICU-acquired infection was similar for men (46.5%) and women (44.5%). All-cause in-hospital mortality was 12.7% for trauma male patient and 9.1% for trauma female patient (p = 0.065) and 22.9% for nontrauma male patients and 20.6% for nontrauma female patients (p = 0.40). Among trauma patients, logistic regression analysis identified female sex as protective for all-cause mortality (odds ratio, 0.57). Among trauma patients, men had significantly higher admission serum levels of interleukin-2, interleukin-12, interferon-γ, and tumor necrosis factor-α, and among nontrauma patients, men had higher admission levels of interleukin-8 and tumor necrosis factor-α.

CONCLUSIONS

The relationship between sex and outcomes in critically ill patients is complex and depends on underlying illness. Women appear to be better adapted to survive traumatic events, while sex may be less important in other forms of critical illness. The mechanisms accounting for this gender dimorphism may, in part, involve differential cytokine responses to injury, with men expressing a more robust proinflammatory profile.

End-stage renal disease and outcome in a surgical intensive care unit

Introduction

End-stage renal disease (ESRD) is associated with an increased propensity for critical illness, but whether ESRD is independently associated with a greater risk of death after major surgical procedures is unclear.

Methods

This was a retrospective analysis of prospectively collected data from all adult (>18 years) patients admitted to a 50-bed surgical intensive care unit (ICU) between January 2004 and January 2009. ESRD was defined as the need for chronic peritoneal dialysis or hemodialysis for at least 6 weeks prior to ICU admission. We used multivariable logistic regression analysis and propensity-score matching to adjust for possible confounders.

Results

In total, 12,938 adult patients were admitted during the study period; 199 patients had ESRD at ICU admission, giving a prevalence of 1.5%. Patients with ESRD were more likely to be male (72.9% versus 63.0%, P = 0.004) and had higher severity scores, a higher incidence of diabetes mellitus and cirrhosis, and a lower incidence of cancer at ICU admission than those without ESRD. Patients with ESRD were more likely to have any type of organ failure at ICU admission and during the ICU stay. Patients with ESRD had higher ICU and hospital mortality rates (23.1% and 31.2% versus 5.5% and 10.0%, respectively, P <0.001 pairwise) and longer ICU length of stay (2 (1 to 7) versus 1 (1 to 3) days, P <0.001). In multivariable logistic regression analysis, ESRD was independently associated with a greater risk of in-hospital death (odds ratio = 3.84, 95% confidence interval 2.68 to 5.5, P <0.001). In 199 pairs of patients, hematologic and hepatic failures were more prevalent, ICU and hospital mortality rates were higher (23.1% versus 15.1% and 31.2% versus 19.1%, P <0.05 pairwise), and ICU length of stay was longer (2 (1 to 7) versus 1 (1 to 7) days, P <0.001) in patients with ESRD.

Conclusions

In this large cohort of surgical ICU patients, presence of ESRD at ICU admission was associated with greater morbidity and mortality and independently associated with a greater risk of in-hospital death. Our data can be useful in preoperative risk stratification.

Sepsis: multiple abnormalities, heterogeneous responses, and evolving understanding

Sepsis represents the host's systemic inflammatory response to a severe infection. It causes substantial human morbidity resulting in hundreds of thousands of deaths each year. Despite decades of intense research, the basic mechanisms still remain elusive. In either experimental animal models of sepsis or human patients, there are substantial physiological changes, many of which may result in subsequent organ injury. Variations in age, gender, and medical comorbidities including diabetes and renal failure create additional complexity that influence the outcomes in septic patients. Specific system-based alterations, such as the coagulopathy observed in sepsis, offer both potential insight and possible therapeutic targets. Intracellular stress induces changes in the endoplasmic reticulum yielding misfolded proteins that contribute to the underlying pathophysiological changes. With these multiple changes it is difficult to precisely classify an individual's response in sepsis as proinflammatory or immunosuppressed. This heterogeneity also may explain why most therapeutic interventions have not improved survival. Given the complexity of sepsis, biomarkers and mathematical models offer potential guidance once they have been carefully validated. This review discusses each of these important factors to provide a framework for understanding the complex and current challenges of managing the septic patient. Clinical trial failures and the therapeutic interventions that have proven successful are also discussed.

Absence of gender-based differences in outcome of patients with hospital-acquired pneumonia

BACKGROUND

The objective of this analysis was to evaluate the association between gender and clinical outcomes in intensive care unit (ICU) patients with hospital-acquired pneumonia (HAP) since data thus far are controversial.

METHODS

Data from a convenience sample of ICU patients with HAP, including ventilator-associated and health care-associated pneumonia, were retrospectively collected from four academic institutions (Improving Medicine through Pathway Assessment of Critical Therapy in Hospital-Acquired Pneumonia [IMPACT-HAP] study). Outcomes included 28-day mortality, clinical failure at day 14, hospital and ICU length of stay (LOS), and duration of mechanical ventilation. We compared baseline characteristics and performed multivariate analysis to identify factors independently associated with mortality.

RESULTS

Among 416 patients, 271 were men and 145 were women. Women were older (62.4±16.9 vs. 55.7±16.5 years, p<0.001) and more critically ill, with Acute Physiology and Chronic Health Evaluation (APACHE) II scores of 21 vs. 19 (p=0.004). Day-28 mortality was 30% for women and 24% for men (p=0.25). Increased 28-day mortality was associated with severity of illness, age, ventilator-associated pneumonia, vascular disease, and hospital LOS prior to pneumonia diagnosis. No significant differences were found in the distribution of bacteria pathogens or in clinical failure rates (36% vs. 31%) between genders. Duration in days of mechanical ventilation, ICU LOS and hospital LOS after the diagnosis of pneumonia were not significantly different between men and women. Analyzing data for women based on presumed pre- or postmenopausal status (age breakpoint of 50 years), showed an increased in ICU LOS (15 vs. 25 days; p=0.0026) and hospital LOS (22 vs. 30 days; p=0.05) for women ≤50 years. No differences were noted in 28-day mortality (24.3% vs. 13.1%; p=0.18) in women ≤50 years of age.

CONCLUSIONS

In ICU patients with pneumonia, female gender was not associated with worse outcomes or increased resource utilization compared to male gender. Further studies are needed to evaluate menopausal status and outcomes in women with pneumonia.

The influence of gender on the epidemiology of and outcome from severe sepsis

INTRODUCTION

The impact of gender on outcome in critically ill patients is unclear. We investigated the influence of gender on the epidemiology of severe sepsis and associated morbidity and mortality in a large cohort of ICU patients in the region of Piedmont in Italy.

METHODS

This was a post-hoc analysis of data from a prospective, multicenter, observational study in which all patients admitted to one of 24 participating medical and/or surgical ICUs between 3 April 2006 and 29 September 2006 were included.

RESULTS

Of the 3,902 patients included in the study, 63.5% were male. Female patients were significantly older than male patients (66±16 years vs. 63±16 years, P<0.001). Female patients were less likely to have severe sepsis and septic shock on admission to the ICU and to develop these syndromes during the ICU stay. ICU mortality was similar in men and women in the whole cohort (20.1% vs. 19.8%, P=0.834), but in patients with severe sepsis was significantly greater in women than in men (63.5% vs. 46.4%, P=0.007). In multivariate logistic regression analysis with ICU outcome as the dependent variable, female gender was independently associated with a higher risk of ICU death in patients with severe sepsis (odds ratio=2.33, 95% confidence interval=1.23 to 4.39, P=0.009) but not in the whole cohort (odds ratio=1.07, 95% confidence interval=0.87 to 1.34).

CONCLUSION

In this large regional Italian cohort of ICU patients, there were more male than female admissions. The prevalence of severe sepsis was lower in women than in men, but female gender was independently associated with a higher risk of death in the ICU for patients with severe sepsis.

Ventilator-associated pneumonia and ICU mortality in severe ARDS patients ventilated according to a lung-protective strategy

INTRODUCTION

Ventilator-associated pneumonia (VAP) may contribute to the mortality associated with acute respiratory distress syndrome (ARDS). We aimed to determine the incidence, outcome, and risk factors of bacterial VAP complicating severe ARDS in patients ventilated by using a strictly standardized lung-protective strategy.

METHODS

This prospective epidemiologic study was done in all the 339 patients with severe ARDS included in a multicenter randomized, placebo-controlled double-blind trial of cisatracurium besylate in severe ARDS patients. Patients with suspected VAP underwent bronchoalveolar lavage to confirm the diagnosis.

RESULTS

Ninety-eight (28.9%) patients had at least one episode of microbiologically documented bacterial VAP, including 41 (41.8%) who died in the ICU, compared with 74 (30.7%) of the 241 patients without VAP (P = 0.05). After adjustment, age and severity at baseline, but not VAP, were associated with ICU death. Cisatracurium besylate therapy within 2 days of ARDS onset decreased the risk of ICU death. Factors independently associated with an increased risk to develop a VAP were male sex and worse admission Glasgow Coma Scale score. Tracheostomy, enteral nutrition, and the use of a subglottic secretion-drainage device were protective.

CONCLUSIONS

In patients with severe ARDS receiving lung-protective ventilation, VAP was associated with an increased crude ICU mortality which did not remain significant after adjustment.

Does sex affect 30-day mortality in Staphylococcus aureus bacteremia?

BACKGROUND

Sex-related differences in complications and mortality of infection were examined with conflicting results. Further studies are required to bring new light in this topic in Staphylococcus aureus infections.

OBJECTIVE

We examined the outcomes of S. aureus infection in men and in women and whether sex-related differences were explained by underlying disorders, severity of disease, or clinical management.

METHODS

This cohort study was conducted in a single center between 1988 and 2007. Patients with clinically significant S. aureus bacteremia were included. We compared 30-day all-cause mortality in men and women. We used multivariable logistic regression analysis to test whether sex was independently associated with mortality.

RESULTS

One thousand ninety-three patients were identified with S. aureus bacteremia. All-cause mortality at day 30 was 39.3% (508 of 1293 patients): 44.8% (238 of 531 patients) in women and 35.4% (270 of 762 patients) in men (P < 0.01). In a multivariate analysis, female sex was associated with higher mortality (odds ratio = 1.63; 95% CI, 1.07-2.47). The excess mortality in women was not explained by differences in demographic characteristic factors, background conditions, infection severity and management, or septic complications.

CONCLUSIONS

We found that women with S. aureus bacteremia had a greater risk of 30-day all-cause mortality than men, even when adjusting for other risk factors. However, we failed to explain this excess of mortality.

Association of gender with outcomes in critically ill patients

Introduction

The influence of gender on mortality and other outcomes of critically ill patients is not clear. Different studies have been performed in various settings and patient populations often yielding conflicting results. We wanted to assess the relationship of gender and intensive care unit (ICU) outcomes in the patients included in the Acute Physiology and Chronic Health Evaluation (APACHE) IV database (Cerner Corporation, USA).

Methods

We performed a retrospective review of the data available in the APACHE IV database. A total of 261,255 consecutive patients admitted to adult ICUs in United States from 1 January 2004 to 31 December 2008 were included. Readmissions were excluded from the analysis. The primary objective of the study was to assess the relationship of gender with ICU mortality. The secondary objective was to evaluate the association of gender with active therapy, mechanical ventilation, length of stay in the ICU, readmission rate and hospital mortality. The gender-related outcomes for disease subgroups including acute coronary syndrome, coronary artery bypass graft (CABG) surgery, sepsis, trauma and chronic obstructive pulmonary disease (COPD) exacerbation were assessed as well.

Results

ICU mortality was 7.2% for men and 7.9% for women, odds ratio (OR) for death for women was 1.07 (95% confidence interval (CI): 1.04 to 1.1). There was a statistically significant interaction between gender and age. In patients <50 years of age, women had a reduced ICU mortality compared with men, after adjustment for acute physiology score, ethnicity, co-morbid conditions, pre-ICU length of stay, pre-ICU location and hospital teaching status (adjusted OR 0.83, 95% CI: 0.76 to 0.91). But among patients ≥50 years of age, there was no significant difference in ICU mortality between men and women (adjusted OR 1.02, 95% CI: 0.98 to 1.06).

A higher proportion of men received mechanical ventilation, emergent surgery, thrombolytic therapy and CABG surgery. Men had a higher readmission rate and longer length of ICU stay. The adjusted mortality of women compared to men was higher with CABG, while it was lower with COPD exacerbation. There was no significant difference in mortality in acute coronary syndrome, sepsis and trauma.

Conclusions

Among the critically ill patients, women less than 50 years of age had a lower ICU mortality compared to men, while 50 years of age or older women did not have a significant difference compared to men. Women had a higher mortality compared to men after CABG surgery and lower mortality with COPD exacerbation. There was no difference in mortality in acute coronary syndrome, sepsis or trauma.

Sexual dimorphism in hematocrit response following red blood cell transfusion of critically ill surgical patients

The change in hematocrit (ΔHct) following packed red blood cell (pRBCs) transfusion is a clinically relevant measurement of transfusion efficacy that is influenced by post-transfusion hemolysis. Sexual dimorphism has been observed in critical illness and may be related to gender-specific differences in immune response. We investigated the relationship between both donor and recipient gender and ΔHct in an analysis of all pRBCs transfusions in our surgical intensive care unit (2006–2009). The relationship between both donor and recipient gender and ΔHct (% points) was assessed using both univariate and multivariable analysis. A total of 575 units of pRBCs were given to 342 patients; 289 (49.9%) donors were male. By univariate analysis, ΔHct was significantly greater for female as compared to male recipients (3.81% versus 2.82%, resp., P < 0.01). No association was observed between donor gender and ΔHct, which was 3.02% following receipt of female blood versus 3.23% following receipt of male blood (P = 0.21). By multivariable analysis, recipient gender remained associated significantly with ΔHct (P < 0.01). In conclusion, recipient gender is independently associated with ΔHct following pRBCs transfusion. This association does not appear related to either demographic or anthropomorphic factors, raising the possibility of gender-related differences in recipient immune response to transfusion.

Gender influences outcomes in trauma patients with elevated systolic blood pressure

BACKGROUND

This analysis explored the association between gender and systolic blood pressure (SBP) in trauma patients and then established how gender influenced outcomes in those with elevated SBP.

METHODS

Demographics and outcomes were compared using the Los Angeles County Trauma System Database and multivariable modeling determined predictors for SBP, pneumonia, and mortality.

RESULTS

Age and male sex were significant predictors for increased SBP, whereas the Injury Severity Score (ISS) ≥16 was a significant predictor for decreased SBP. In both male and female TBI patients, SBP ≥160 mmHg was associated with increased pneumonia (Adjusted odds ratio [AOR] = 1.74, P = .002 and AOR = 2.37, P = .046, respectively), whereas SBP ≥160 mmHg was a predictor for mortality only among male TBI patients (AOR = 1.48, P = .03). In non-TBI patients, SBP ≥160 mmHg was not a predictor for pneumonia or mortality in either sex.

CONCLUSIONS

In this retrospective review of trauma registry data, men presented with higher SBP. In patients with TBI, regardless of gender, increased SBP was associated with increased pneumonia, and in men with TBI increased SBP was associated with increased mortality. The cause and relevance of these epidemiological findings require further investigation.

Short women with severe sepsis-related acute lung injury receive lung protective ventilation less frequently: an observational cohort study

Introduction

Lung protective ventilation (LPV) has been shown to improve survival and the duration of mechanical ventilation in acute lung injury (ALI) patients. Mortality of ALI may vary by gender, which could result from treatment variability. Whether gender is associated with the use of LPV is not known.

Methods

A total of 421 severe sepsis-related ALI subjects in the Consortium to Evaluate Lung Edema Genetics from seven teaching hospitals between 2002 and 2008 were included in our study. We evaluated patients' tidal volume, plateau pressure and arterial pH to determine whether patients received LPV during the first two days after developing ALI. The odds ratio of receiving LPV was estimated by a logistic regression model with robust and cluster options.

Results

Women had similar characteristics as men with the exception of lower height and higher illness severity, as measured by Acute Physiology and Chronic Health Evaluation (APACHE) II score. 225 (53%) of the subjects received LPV during the first two days after ALI onset; women received LPV less frequently than men (46% versus 59%, P < 0.001). However, after adjustment for height and severity of illness (APACHE II), there was no difference in exposure to LPV between men and women (P = 0.262).

Conclusions

Short people are less likely to receive LPV, which seems to explain the tendency of clinicians to adhere to LPV less strictly in women. Strategies to standardize application of LPV, independent of differences in height and severity of illness, are necessary.

Gender-related outcome difference is related to course of sepsis on mixed ICUs: a prospective, observational clinical study

INTRODUCTION

Impact of gender on severe infections is in highly controversial discussion with natural survival advantage of females described in animal studies but contradictory to those described human data. This study aims to describe the impact of gender on outcome in mixed intensive care units (ICUs) with a special focus on sepsis.

METHODS

We performed a prospective, observational, clinical trial at Charité University Hospital in Berlin, Germany. Over a period of 180 days, patients were screened, undergoing care in three mainly surgical ICUs. In total, 709 adults were included in the analysis, comprising the main population ([female] n = 309, [male] n = 400) including 327 as the sepsis subgroup ([female] n = 130, [male] n = 197).

RESULTS

Basic characteristics differed between genders in terms of age, lifestyle factors, comorbidities, and SOFA-score (Sequential Organ Failure Assessment). Quality and quantity of antibiotic therapy in means of antibiotic-free days, daily antibiotic use, daily costs of antibiotics, time to antibiotics, and guideline adherence did not differ between genders. ICU mortality was comparable in the main population ([female] 10.7% versus [male] 9.0%; P = 0.523), but differed significantly in sepsis patients with [female] 23.1% versus [male] 13.7% (P = 0.037). This was confirmed in multivariate regression analysis with OR = 1.966 (95% CI, 1.045 to 3.701; P = 0.036) for females compared with males.

CONCLUSIONS

No differences in patients' outcome were noted related to gender aspects in mainly surgical ICUs. However, for patients with sepsis, an increase of mortality is related to the female sex.

Gender differences in mortality in patients with severe sepsis or septic shock

BACKGROUND

Although the incidence of sepsis is higher in men than in women, it is controversial whether there are sex-based differences in sepsis-associated mortality.

OBJECTIVE

The aim of this study was to test the hypothesis that hospital mortality is higher in males compared with females with severe sepsis/septic shock who require intensive care.

METHODS

This was a retrospective cohort study of intensive care unit (ICU) patients hospitalized (in 98 ICUs in 71 US hospitals and 4 Canadian or Brazilian hospitals) with severe sepsis/septic shock between mid-2003 and 2006, using data from the Cerner Project IMPACT database.

RESULTS

Data were analyzed for 18,757 ICU patients (median age, 66 years; interquartile range, 53-77 years), including 8702 females (46%). Hospital mortality was higher in female patients compared with male patients (35% vs 33%, respectively; P = 0.006). After adjusting for differences in baseline characteristics and processes of care, females had a higher likelihood of hospital mortality than did males (odds ratio [OR] = 1.11; 95% CI, 1.04-1.19; P = 0.002). Female patients were less likely than male patients to receive deep venous thrombosis prophylaxis (OR = 0.90; 95% CI, 0.84-0.97), invasive mechanical ventilation (OR = 0.81; 95% CI, 0.76-0.86), or hemodialysis catheters (OR = 0.85; 95% CI, 0.78-0.93). Females were more likely than males to receive red blood cell transfusions (OR = 1.15; 95% CI, 1.09-1.22) and code status limitations (OR = 1.31; 95% CI, 1.18-1.47).

CONCLUSIONS

In this large cohort of ICU patients, females with severe sepsis/septic shock had a higher risk of dying in the hospital than did males. This difference remained after multivariable adjustment. Significant gender disparities were also found in some aspects of care delivery, but these did not explain the higher mortality in female patients.

Race/Ethnicity is not associated with mortality in the PICU

OBJECTIVE

To determine if a difference in survival exists between children of different racial/ethnic groups who were admitted to the PICU, after controlling for severity of illness (pediatric index of mortality 2).

METHODS

We used the largest national clinical PICU database (Virtual PICU Performance System) with data from 31 hospitals, from 2005 to 2008. Children 18 years and younger were included. We collected demographic, pediatric index of mortality 2, diagnosis, and PICU mortality data. Logistic regression models were constructed to identify PICU mortality risk factors.

RESULTS

The analysis of 80 739 patients revealed that, after controlling for severity of illness, being female (odds ratio [OR]: 1.12 [95% confidence interval (CI): 1.02-1.24] P = .019), 1 month or younger (OR: 1.39 [95% CI: 1.17-1.65] P < .001) or 12 years or older (OR: 1.34 [95% CI: 1.17-1.52] P < .001), or having an infectious diagnosis (OR: 2.22 [95% CI: 1.83-2.71] P < .001) or oncologic diagnosis (OR: 1.50 [95% CI: 1.14-1.99] P = .004) increased PICU mortality. Having "other" insurance type (OR: 1.58 [95% CI: 1.11-2.24] P = .010) or being Asian/Indian/Pacific Islander (OR: 1.35 [95% CI: 1.01-1.81] P = .042) seemed also to be mortality risk factors; however, because of heterogeneity and small group sizes (1.7% and 2.5% of the study population, respectively), these results are inconclusive.

CONCLUSIONS

Although gender, age, and diagnosis showed an effect on severity of illness-adjusted PICU mortality, race/ethnicity did not. Additional investigation is warranted because the present results (ie, insurance type) may be proxy measurements for other influences not collected in this database, such as sociocultural and socioeconomic factors.

Hormonal status in protracted critical illness and in-hospital mortality

Introduction

The aim of this study was to determine the relationship between hormonal status and mortality in patients with protracted critical illness.

Methods

We conducted a prospective observational study in four medical and surgical intensive care units (ICUs). ICU patients who regained consciousness after 7 days of mechanical ventilation were included. Plasma levels of insulin-like growth factor 1 (IGF-1), prolactin, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, estradiol, progesterone, testosterone, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS) and cortisol were measured on the first day patients were awake and cooperative (day 1). Mean blood glucose from admission to day 1 was calculated.

Results

We studied 102 patients: 65 men and 37 women (29 of the women were postmenopausal). Twenty-four patients (24%) died in the hospital. The IGF-1 levels were higher and the cortisol levels were lower in survivors. Mean blood glucose was lower in women who survived, and DHEA and DHEAS were higher in men who survived.

Conclusions

These results suggest that, on the basis of sex, some endocrine or metabolic markers measured in the postacute phase of critical illness might have a prognostic value.

Metabolomic analysis in severe childhood pneumonia in the Gambia, West Africa: findings from a pilot study

BACKGROUND

Pneumonia remains the leading cause of death in young children globally and improved diagnostics are needed to better identify cases and reduce case fatality. Metabolomics, a rapidly evolving field aimed at characterizing metabolites in biofluids, has the potential to improve diagnostics in a range of diseases. The objective of this pilot study is to apply metabolomic analysis to childhood pneumonia to explore its potential to improve pneumonia diagnosis in a high-burden setting.

METHODOLOGY/PRINCIPAL FINDINGS

Eleven children with World Health Organization (WHO)-defined severe pneumonia of non-homogeneous aetiology were selected in The Gambia, West Africa, along with community controls. Metabolomic analysis of matched plasma and urine samples was undertaken using Ultra Performance Liquid Chromatography (UPLC) coupled to Time-of-Flight Mass Spectrometry (TOFMS). Biomarker extraction was done using SIMCA-P+ and Random Forests (RF). 'Unsupervised' (blinded) data were analyzed by Principal Component Analysis (PCA), while 'supervised' (unblinded) analysis was by Partial Least Squares-Discriminant Analysis (PLS-DA) and Orthogonal Projection to Latent Structures (OPLS). Potential markers were extracted from S-plots constructed following analysis with OPLS, and markers were chosen based on their contribution to the variation and correlation within the data set. The dataset was additionally analyzed with the machine-learning algorithm RF in order to address issues of model overfitting and markers were selected based on their variable importance ranking. Unsupervised PCA analysis revealed good separation of pneumonia and control groups, with even clearer separation of the groups with PLS-DA and OPLS analysis. Statistically significant differences (p<0.05) between groups were seen with the following metabolites: uric acid, hypoxanthine and glutamic acid were higher in plasma from cases, while L-tryptophan and adenosine-5'-diphosphate (ADP) were lower; uric acid and L-histidine were lower in urine from cases. The key limitation of this study is its small size.

CONCLUSIONS/SIGNIFICANCE

Metabolomic analysis clearly distinguished severe pneumonia patients from community controls. The metabolites identified are important for the host response to infection through antioxidant, inflammatory and antimicrobial pathways, and energy metabolism. Larger studies are needed to determine whether these findings are pneumonia-specific and to distinguish organism-specific responses. Metabolomics has considerable potential to improve diagnostics for childhood pneumonia.