Risk Prediction With Procalcitonin and Clinical Rules in Community-Acquired Pneumonia

Abstract

Objective-The Pneumonia Severity Index (PSI) and CURB-65 predict outcomes in community acquired pneumonia (CAP), but have limitations. Procalcitonin, a biomarker of bacterial infection, may provide prognostic information in CAP. Our objective was to describe the pattern of procalcitonin in CAP, and determine if procalcitonin provides prognostic information beyond PSI and CURB-65.Methods-We conducted a multi-center prospective cohort study in 28 community and teaching emergency departments. Patients presenting with a clinical and radiographic diagnosis of CAP were enrolled. We stratified procalcitonin levels a priori into four tiers -I: < 0.1; II: ≥ 0.1 to <0.25; III: ≥ 0.25 to < 0.5; and IV: ≥ 0.5 ng/ml. Primary outcome was 30d mortality.Results-1651 patients formed the study cohort. Procalcitonin levels were broadly spread across tiers: 32.8% (I), 21.6% (II), 10.2% (III), 35.4% (IV). Used alone, procalcitonin had modest test characteristics: specificity (35%), sensitivity (92%), positive likelihood ratio (LR) (1.41), and negative LR (0.22). Adding procalcitonin to PSI in all subjects minimally improved performance. Adding procalcitonin to low risk PSI subjects (Class I-III) provided no additional information. However, subjects in procalcitonin tier I had low 30d mortality regardless of clinical risk, including those in higher risk classes (1.5% vs. 1.6% for those in PSI Class I-III vs. Class IV/V). Among high risk PSI subjects (Class IV/V), one quarter (126/546) were in procalcitonin tier I, and the negative LR of procalcitonin tier I was 0.09. Procalcitonin tier I was also associated with lower burden of other adverse outcomes. Similar results were seen with CURB-65 stratification. Reprints not available from the authors.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Conclusions-Selective use of procalcitonin as an adjunct to existing rules may offer additional prognostic information in high risk patients. NIH Public Access

Prevalence and Significance of Coagulation Abnormalities in Community-Acquired Pneumonia

“…We obtained approval from the institutional review boards of the University of Pittsburgh and all participating sites. Other results of this study, not including the coagulation data we report here, have been published elsewhere (5,14). Some of the results of this study have been published in the form of an abstract (15).…”

Inflammatory responses predict long-term mortality risk in community-acquired pneumonia

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