Chest
Volume 129, Issue 4, April 2006, Pages 968-978
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Original Research
Severe Sepsis in Community-Acquired Pneumonia: When Does It Happen, and Do Systemic Inflammatory Response Syndrome Criteria Help Predict Course?

https://doi.org/10.1378/chest.129.4.968Get rights and content

Study objectives

Most natural history studies of severe sepsis are limited to ICU populations. We describe the onset and timing of severe sepsis during the hospital course for patients hospitalized with community-acquired pneumonia (CAP). We also determine the ability of the systemic inflammatory response syndrome (SIRS) and other proposed risk stratification scores measured at emergency department (ED) presentation to predict progression to severe sepsis, septic shock, or death.

Design

Retrospective analysis of a prospective observational outcome study from the Pneumonia Patient Outcomes Research Team (PORT).

Setting

Four academic medical centers in the United States and Canada between October 1991 and March 1994.

Participants

The 1,339 patients hospitalized for CAP in the PORT study cohort, and a random subset of 686 patients for whom we had information for SIRS criteria.

Interventions

None.

Measurements and results

All subjects had infection (CAP). Severe sepsis was defined as new-onset acute organ dysfunction in this cohort, using consensus criteria. Severe sepsis developed in one half of the patients (n = 639, 48%), nonpulmonary organ dysfunction developed in 520 patients (39%), and septic shock developed in 61 subjects (4.5%). Severe sepsis and septic shock were present at ED presentation in 457 patients (71% of severe sepsis cases) and 27 patients (44% of septic shock cases), respectively. While SIRS was common at presentation (82% of the subset of 686 had two SIRS criteria), it was not associated with increased odds for progression to severe sepsis (odds ratios [ORs], 0.65 and 0.89 for two or more SIRS criteria and three or more SIRS criteria, respectively), septic shock (ORs, 0.80 and 0.55), or death (ORs, 0.65 and 0.39), with poor discrimination (all receiver operating characteristic [ROC] areas under the curve < 0.5). The pneumonia severity index was associated with severe sepsis (p < 0.001) with moderate discrimination (ROC, 0.63).

Conclusions

Severe sepsis is common in hospitalized CAP patients, occurring early in the hospital course. SIRS criteria do not appear to be useful predictors for progression to severe sepsis in CAP.

Section snippets

Materials and Methods

The Institutional Review Board of the University of Pittsburgh approved this research study. All participants signed an informed consent form.

Results

Of the 2,287 patients enrolled in the PORT cohort in the ED, 1,343 patients were admitted. Of the 1,343 patients, 1,339 patients had complete organ dysfunction data and formed the study population. Of these 1,339 patients, 170 patients (12.7%) were admitted to the ICU at some point. We described the baseline characteristics of the study population previously.22 One half of the patients (n = 669, 49.96%) had a PSI class of IV or V, conferring a 30-day mortality risk of ≥ 8.5%.15 We collected the

Discussion

We demonstrated that SIRS criteria measured as early as the patient's presentation to the ED are poorly predictive of severe sepsis, shock, and death in pneumonia patients. Once the cornerstone of the sepsis definition, SIRS appears to be of very limited use in forecasting any of the adverse events in the sepsis cascade. Our results show for the first time that this holds true for a mixture of ICU and non-ICU patients even when SIRS is present very early during their hospital course. However,

Appendix

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    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

    This research was partly funded by the Agency for Health Care Policy and Research (R01 HSO 6468) as part of the Pneumonia Patient Outcomes Research Team, and by the National Institute of General Medical Sciences (R01 GM61992) as part of the Genetic and Inflammatory Markers of Sepsis project.

    The work was performed at the University of Pittsburgh, Pittsburgh, PA.

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