title: Procalcitonin predicts patients at low risk of death from community-acquired pneumonia across all CRB-65 classes.
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.
authors.affiliation: Dept of Internal Medicine II, Ulm University Hospital, Ulm, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Krüger
authors.forename: S
authors.initials: S
authors.lastname: Ewig
authors.forename: R
authors.initials: R
authors.lastname: Marre
authors.forename: J
authors.initials: J
authors.lastname: Papassotiriou
authors.forename: K
authors.initials: K
authors.lastname: Richter
authors.forename: H
authors.initials: H
authors.lastname: von Baum
authors.forename: N
authors.initials: N
authors.lastname: Suttorp
authors.forename: T
authors.initials: T
authors.lastname: Welte
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D019540:Area Under Curve; D015415:Biomarkers / Q000032:analysis; D002097:C-Reactive Protein / Q000378:metabolism; D002116:Calcitonin / Q000032:analysis / Q000378:metabolism*; D015740:Calcitonin Gene-Related Peptide; D002423:Cause of Death; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000175:diagnosis* / Q000401:mortality* / Q000503:physiopathology; D003221:Confusion / Q000503:physiopathology; D005260:Female; D005858:Germany; D006801:Humans; D007022:Hypotension / Q000175:diagnosis; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000175:diagnosis* / Q000401:mortality* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011498:Protein Precursors / Q000032:analysis / Q000378:metabolism*; D012119:Respiration; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D016019:Survival Analysis
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide