Unnecessary antibiotic use importantly contributes to increasing bacterial resistance and increases medical costs and the risks of drug-related adverse events.^1-3 The most frequent indication for antibiotic prescriptions in the northwestern hemisphere is lower respiratory tract infections (LRTIs), which range in severity from self-limited acute bronchitis to severe acute exacerbation of chronic obstructive pulmonary disease (COPD), and to life-threatening bacterial community-acquired pneumonia (CAP).⁴ Clinical signs and symptoms, as well as commonly used laboratory markers, are unreliable in distinguishing viral from bacterial LRTI.^5-7 As many as 75% of patients with LRTI are treated with antibiotics, despite the predominantly viral origin of their infection.⁸

Introduction: Measurement of prohormones representing different pathophysiological pathways could enhance risk stratification in patients with community-acquired pneumonia (CAP) and other lower respiratory tract infections (LRTI). Methods: We assessed clinical parameters and five biomarkers, the precursor levels of adrenomedullin (ADM), endothelin-1 (ET1), atrial-natriuretic peptide (ANP), anti-diuretic hormone (copeptin), and procalcitonin in patients with LRTI and CAP enrolled in the multicenter ProHOSP study. We compared the prognostic accuracy of these biomarkers with the pneumonia severity index (PSI) and CURB65 (Confusion, Urea, Respiratory rate, Blood pressure, Age 65) score to predict serious complications defined as death, ICU admission and disease-specific complications using receiver operating curves (ROC) and reclassification methods. Results: During the 30 days of follow-up, 134 serious complications occurred in 925 (14.5%) patients with CAP. Both PSI and CURB65 overestimated the observed mortality (X² goodness of fit test: P = 0.003 and 0.01). ProADM or proET1 alone had stronger discriminatory powers than the PSI or CURB65 score or any of either score components to predict serious complications. Adding proADM alone (or all five biomarkers jointly) to the PSI and CURB65 scores, significantly increased the area under the curve (AUC) for PSI from 0.69 to 0.75, and for CURB65 from 0.66 to 0.73 (P < 0.001, for both scores). Reclassification methods also established highly significant improvement (P < 0.001) for models with biomarkers if clinical covariates were more flexibly adjusted for. The developed prediction models with biomarkers extrapolated well if evaluated in 434 patients with non-CAP LRTIs. Conclusions: Five biomarkers from distinct biologic pathways were strong and specific predictors for short-term adverse outcome and improved clinical risk scores in CAP and non-pneumonic LRTI. Intervention studies are warranted to show whether an improved risk prognostication with biomarkers translates into a better clinical management and superior allocation of health care resources. Trial Registration: NCT00350987.

Our aim was to evaluate the benefits and harms of adjunctive corticosteroids in adults hospitalized with community-acquired pneumonia (CAP) using individual patient data from randomized, placebo-controlled trials and to explore subgroup differences. We systematically searched Medline, Embase, Cochrane Central, and trial registers (all through July 2017). Data from 1506 individual patients in 6 trials were analyzed using uniform outcome definitions. We investigated prespecified effect modifiers using multivariable hierarchical regression, adjusting for pneumonia severity, age, and clustering effects. Within 30 days of randomization, 37 of 748 patients (5.0%) assigned to corticosteroids and 45 of 758 patients (5.9%) assigned to placebo died (adjusted odds ratio [aOR], 0.75; 95% confidence interval [CI], .46 to 1.21; P = .24). Time to clinical stability and length of hospital stay were reduced by approximately 1 day with corticosteroids (–1.03 days; 95% CI, –1.62 to –.43; P = .001 and –1.15 days; 95% CI, –1.75 to –.55; P < .001, respectively). More patients with corticosteroids had hyperglycemia (160 [22.1%] vs 88 [12.0%]; aOR, 2.15; 95% CI, 1.60 to 2.90; P < .001) and CAP-related rehospitalization (33 [5.0%] vs 18 [2.7%]; aOR, 1.85; 95% CI, 1.03 to 3.32; P = .04). We did not find significant effect modification by CAP severity or degree of inflammation. Adjunct corticosteroids for patients hospitalized with CAP reduce time to clinical stability and length of hospital stay by approximately 1 day without a significant effect on overall mortality but with an increased risk for CAP–related rehospitalization and hyperglycemia.

Neutrophil extracellular traps (NETs) are a hallmark of the immune response in inflammatory diseases. However, the role of NETs in community-acquired pneumonia (CAP) is unknown. This study aims to characterise the impact of NETs on clinical outcomes in pneumonia.This is a secondary analysis of a randomised controlled, multicentre trial. Patients with CAP were randomly assigned to either 50 mg prednisone or placebo for 7 days. The primary end-point was time to clinical stability; main secondary end-points were length of hospital stay and mortality.In total, 310 patients were included in the analysis. Levels of cell-free nucleosomes as surrogate markers of NETosis were significantly increased at admission and declined over 7 days. NETs were significantly associated with reduced hazards of clinical stability and hospital discharge in multivariate adjusted analyses. Moreover, NETs were associated with a 3.8-fold increased adjusted odds ratio of 30-day mortality. Prednisone treatment modified circulatory NET levels and was associated with beneficial outcome.CAP is accompanied by pronounced NET formation. Patients with elevated serum NET markers were at higher risk for clinical instability, prolonged length of hospital stay and 30-day all-cause mortality. NETs represent a novel marker for outcome and a possible target for adjunct treatments of pneumonia.