title: Usefulness of plasma procalcitonin to predict severity in elderly patients with community-acquired pneumonia.
abstract: BACKGROUND
  Community-acquired pneumonia (CAP) is one of the leading causes of death among the elderly. Several studies have reported the clinical usefulness of serum procalcitonin, a biomarker of bacterial infection. However, the association between the levels of procalcitonin and the severity in the elderly with CAP has not yet been reported. The aim of this study was to evaluate usefulness of procalcitonin as a predictor of severity and mortality in the elderly with CAP.
  
  
  METHODS
  This study covers 155 CAP cases admitted to Pusan National University Hospital between January 2010 and December 2010. Patients were divided into two groups (≥65 years, n=99; <65 years, n=56) and were measured for procalcitonin, C-reactive protein (CRP), white blood cell, confusion, uremia, respiratory rate, blood pressure, 65 years or older (CURB-65) and pneumonia severity of index (PSI).
  
  
  RESULTS
  The levels of procalcitonin were significantly correlated with the CURB-65, PSI in totals. Especially stronger correlation was observed between the levels of procalcitonin and CURB-65 in the elderly (procalcitonin and CURB-65, ρ=0.408 with p<0.001; procalcitonin and PSI, ρ=0.293 with p=0.003; procalcitonin and mortality, ρ=0.229 with p=0.023). The correlation between the levels of CRP or WBC and CAP severity was low. The existing cut-off value of procalcitonin was correlated with mortality rate, however, it was not correlated with mortality within the elderly.
  
  
  CONCLUSIONS
  The levels of procalcitonin are more useful than the levels of CRP or WBC to predict the severity of CAP. However, there was no association between the levels of procalcitonin and mortality in the elderly.
authors.affiliation: Department of Internal Medicine, Pusan National University School of Medicine, Busan, Korea.
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Kim
authors.forename: Joo Wan
authors.initials: JW
authors.lastname: Seo
authors.forename: Jeong Ha
authors.initials: JH
authors.lastname: Mok
authors.forename: Mi Hyun
authors.initials: MH
authors.lastname: Kim
authors.forename: Woo Hyun
authors.initials: WH
authors.lastname: Cho
authors.forename: Kwangha
authors.initials: K
authors.lastname: Lee
authors.forename: Ki Uk
authors.initials: KU
authors.lastname: Kim
authors.forename: Doosoo
authors.initials: D
authors.lastname: Jeon
authors.forename: Hye-Kyung
authors.initials: HK
authors.lastname: Park
authors.forename: Yun Seong
authors.initials: YS
authors.lastname: Kim
authors.forename: Hyung Hoi
authors.initials: HH
authors.lastname: Kim
authors.forename: Min Ki
authors.initials: MK
authors.lastname: Lee
keywords: Aged; Community-Acquired Infections; Pneumonia; Procalcitonin