Procalcitonin predicts patients at low risk of death from community-acquired pneumonia across all CRB-65 classes

S Kruger,N Suttorp,R Marre,H Von Baum,S Ewig,T Welte,K Richter,J Papassotiriou

doi:10.1183/09031936.00054507

Abstract

The aim of the present study was to investigate the prognostic value, in patients with community-acquired pneumonia (CAP), of procalcitonin (PCT) compared with the established inflammatory markers C-reactive protein (CRP) and leukocyte (WBC) count alone or in combination with the CRB-65 (confusion, respiratory rate >or=30 breaths x min(-1), low blood pressure (systolic value <90 mmHg or diastolic value <or=60 mmHg) and age >or=65 yrs) score. In total, 1,671 patients with proven CAP were enrolled in the study. PCT, CRP, WBC and CRB-65 score were all determined on admission and patients were followed-up for 28 days for survival. In contrast to CRP and WBC, PCT levels markedly increased with the severity of CAP, as measured by the CRB-65 score. In 70 patients who died during follow-up, PCT levels on admission were significantly higher compared with levels in survivors. In receiver operating characteristic analysis for survival, the area under the curve (95% confidence interval) for PCT and CRB-65 was comparable (0.80 (0.75-0.84) versus 0.79 (0.74-0.84)), but each significantly higher compared with CRP (0.62 (0.54-0.68)) and WBC (0.61 (0.54-0.68)). PCT identified low-risk patients across CRB classes 0-4. In conclusion, procalcitonin levels on admission predict the severity and outcome of community-acquired pneumonia with a similar prognostic accuracy as the CRB-65 score and a higher prognostic accuracy compared with C-reactive protein and leukocyte count. Procalcitonin levels can provide independent identification of patients at low risk of death within CRB-65 (confusion, respiratory rate >or=30 breaths x min(-1), low blood pressure (systolic value <90 mmHg or diastolic value <or=60 mmHg) and age >or=65 yrs) risk classes.

Highlights

In contrast to C-reactive protein (CRP) and WBC, PCT levels markedly increased with the severity of Community-acquired pneumonia (CAP), as measured by the CRB-65 score
The current study demonstrated that PCT levels on admission predict the severity and outcome of CAP with a similar prognostic accuracy as the CRB-65 score and a higher prognostic accuracy compared with WBC and CRP levels
The additional use of PCT using a threshold of f0.228 ng?mL-1 was able to predict patients at very low risk of death within all three risk groups defined by CRB-65

Summary

Introduction

In contrast to CRP and WBC, PCT levels markedly increased with the severity of CAP, as measured by the CRB-65 score. In 70 patients who died during follow-up, PCT levels on admission were significantly higher compared with levels in survivors. Procalcitonin levels on admission predict the severity and outcome of community-acquired pneumonia with a similar prognostic accuracy as the CRB-65 score and a higher prognostic accuracy compared with C-reactive protein and leukocyte count. Prognostic scores for CAP have been developed to assess pneumonia severity in order to validate clinical judgement and to guide decisions about treatment settings [3,4,5,6,7,8,9,10]. In Europe, the CURB (confusion, urea .7 mmol?L-1, respiratory rate o30 breaths?min-1, low blood pressure (systolic value ,90 mmHg or diastolic value f60 mmHg) and age o65 yrs) score or the CRB-65 (confusion, respiratory rate o30 breaths?min-1, low blood pressure (systolic value ,90 mmHg or diastolic value f60 mmHg) and age o65 yrs) score are currently advocated as preferred scores due to their simplicity and applicability in the ambulatory setting [7, 11]

Objectives

Methods

Results

Conclusion