Criteria for clinical stability in hospitalised patients with community-acquired pneumonia.

The American Thoracic Society (ATS) and Infectious Diseases Society of America (IDSA) suggested two sets of criteria in 2001 and 2007 to define clinical stability in community-acquired pneumonia (CAP). The present study aimed to evaluate the level of agreement between these two sets of criteria and how well they can predict clinical outcomes. A retrospective cohort study was carried out of 487 consecutive patients hospitalised with CAP. Level of agreement was tested using a survival curve analysis, while prediction of outcomes at 30-day follow-up was evaluated through receiver operating characteristic (ROC) analysis. A discrepancy between ATS 2001 and ATS/IDSA 2007 criteria in identifying clinical stability was detected in 62% of the patients. The median (interquartile range) time to clinical stability was 2 (1-4) days based on ATS 2001 and 3 (2-5) days based on ATS/IDSA 2007 criteria (p = 0.012). The daily distribution of patients who reached clinical stability evaluated with both sets was different (p = 0.002). The ROC analysis showed an area under the curve of 0.705 for the ATS 2001 criteria and 0.714 for ATS/IDSA 2007 criteria (p = 0.645). ATS 2001 and ATS/IDSA 2007 criteria for clinical stability in hospitalised patients with CAP are clinically equivalent and both can be used in clinical practice as well as in clinical research.

Contrasting inflammatory responses in severe and non-severe community-acquired pneumonia.

The objective of this study was to compare systemic and local cytokine profiles and neutrophil responses in patients with severe versus non-severe community-acquired pneumonia (CAP). Hospitalized patients with CAP were grouped according to the pneumonia severity index (PSI), as non-severe (PSI < 91 points) or severe (PSI ≥ 91 points). Blood and sputum samples were collected upon admission. Compared to non-severe CAP patients, the severe CAP group showed higher plasma levels of pro- and anti-inflammatory cytokines but in contrast, lower sputum concentrations of pro-inflammatory cytokines. Blood neutrophil functional responses were elevated in CAP patients compared to healthy controls. However, neutrophils from severe CAP patients showed reduced respiratory burst activity compared to the non-severe group. Results indicate that patients with severe CAP fail to mount a robust local pro-inflammatory response but exhibit instead a more substantial systemic inflammatory response, suggesting that a key driver of CAP severity may be the ability of the patient to generate an optimal local inflammatory response.