title: The clinical significance of changes in red blood cell distribution width in patients with community-acquired pneumonia.
abstract: OBJECTIVE
  Red cell distribution width (RDW) is associated with mortality in patients with community-acquired pneumonia (CAP). However, little is known about the effect of changes in RDW during treatment on mortality. Thus, the objective of this study was to evaluate the association between RDW changes and mortality in hospitalized patients with CAP.
  
  
  METHODS
  Retrospective analyses were performed using medical records of patients hospitalized for CAP from April 2008 to February 2014. The abstracted laboratory values included RDW (from days one to four), clinical variables, and pneumonia severity index (PSI) scores. The ΔRDWn-1was defined as the change in RDW calculated as: (RDWday1-RDWday-n)/RDWday1×100 (%), where 'day n' refers to hospital day.
  
  
  RESULTS
  During the study period, a total of 1,069 patients were hospitalized for CAP. The 30-day mortality was 100/1,069 (9.4%). The median RDW at baseline was 14.1% (range, 11.1 to 30.2) and differed significantly between survivors and non-survivors (P<0.05). There were 470 patients with available serial RDW data (30-day mortality 58/470 [12.3%]). Of those, age, PSI score, blood urea nitrogen level, total protein concentration, albumin level, RDW at day 1, and the ΔRDW4-1differed significantly between survivors and non-survivors. Multivariate Cox regression analysis showed that the significance of the relationship between ΔRDW4-1and 30-day mortality risk remained after adjusting for age, PSI score, RDW at day 1, total protein concentration, and initial albumin level.
  
  
  CONCLUSIONS
  RDW change from day 1 to day 4 was an independent predictor of mortality in patients with CAP.
authors.affiliation: Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Sang-Min
authors.initials: SM
authors.lastname: Lee
authors.affiliation: Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jae Hyuk
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Kyuseok
authors.initials: K
authors.lastname: Kim
authors.affiliation: Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: You Hwan
authors.initials: YH
authors.lastname: Jo
authors.affiliation: Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jungyoup
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Joonghee
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Hwang
authors.affiliation: Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Young Sang
authors.initials: YS
authors.lastname: Ko
authors.affiliation: Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Chulmin
authors.initials: C
authors.lastname: Ha
authors.affiliation: Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Sujin
authors.initials: S
authors.lastname: Jang
authors.affiliation: Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Hyunmi
authors.initials: H
authors.lastname: Park
keywords: Community-acquired pneumonia; Delta red cell distribution width; Red cell distribution width change