title: Sequence patterns in the resolution of clinical instabilities in community-acquired pneumonia and association with outcomes.
abstract: BACKGROUND
  In patients hospitalized with community-acquired pneumonia (CAP), indicators of clinical instability at discharge (fever, tachycardia, tachypnea, hypotension, hypoxia, decreased oral intake and altered mental status) are associated with poor outcomes. It is not known whether the order of indicator stabilization is associated with outcomes.
  
  
  OBJECTIVE
  To describe variation in the sequences, including whether and in what order, indicators of clinical instability resolve among patients hospitalized with CAP, and to assess associations between patterns of stabilization and patient-level outcomes. DESIGN/PARTICIPANTS / MAIN MEASURES: Chart review ascertained whether and when indicators stabilized and other data for 1,326 adult CAP patients in six U.S. academic medical centers. The sequences of indicator stabilization were characterized using sequence analysis and grouped using cluster analysis. Associations between sequence patterns and 30-day mortality, length of stay (LOS), and total costs were modeled using regression analysis.
  
  
  RESULTS
  We found 986 unique sequences of indicator stabilization. Sequence analysis identified eight clusters of sequences (patterns) derived by the order or speed in which instabilities resolved or remained at discharge and inpatient mortality. Two of the clusters (56% of patients) were characterized by almost complete stabilization prior to discharge alive, but differing in the rank orders of four indicators and time to maximum stabilization. Five other clusters (42% of patients) were characterized by one to three instabilities at discharge with variable orderings of indicator stabilization. In models with fast and almost complete stabilization as the referent, 30-day mortality was lowest in clusters with slow and almost complete stabilization or tachycardia or fever at discharge [OR = 0.73, 95% CI = (0.28-1.92)], and highest in those with hypoxia with instabilities in mental status or oral intake at discharge [OR = 3.99, 95% CI = (1.68-9.50)].
  
  
  CONCLUSIONS
  Sequences of clinical instability resolution exhibit great heterogeneity, yet certain sequence patterns may be associated with differences in days to maximum stabilization, mortality, LOS, and hospital costs.
authors.affiliation: Department of Medicine/Section of Hospital Medicine, University of Chicago, Chicago, IL, USA, ghougham@bsd.uchicago.edu.
authors.forename: Gavin W
authors.initials: GW
authors.lastname: Hougham
authors.forename: Sandra A
authors.initials: SA
authors.lastname: Ham
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Ruhnke
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Schulwolf
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Auerbach
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Schnipper
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kaboli
authors.forename: Tosha B
authors.initials: TB
authors.lastname: Wetterneck
authors.forename: David
authors.initials: D
authors.lastname: Gonzalez
authors.forename: Vineet M
authors.initials: VM
authors.lastname: Arora
authors.forename: David O
authors.initials: DO
authors.lastname: Meltzer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010351:Patient Discharge / Q000639:trends*; D011014:Pneumonia / Q000175:diagnosis* / Q000453:epidemiology* / Q000628:therapy; D012189:Retrospective Studies; D016896:Treatment Outcome