title: Pneumonia Pathogen Characterization Is an Independent Determinant of Hospital Readmission.
abstract: BACKGROUND
  Hospital readmissions for pneumonia occur often and are difficult to predict. For fiscal year 2013, the Centers for Medicare & Medicaid Services readmission penalties have been applied to acute myocardial infarction, heart failure, and pneumonia. However, the overall impact of pneumonia pathogen characterization on hospital readmission is undefined.
  
  
  METHODS
  This was a retrospective 6-year cohort study (August 2007 to September 2013).
  
  
  RESULTS
  We evaluated 9,624 patients with a discharge diagnosis of pneumonia. Among these patients, 4,432 (46.1%) were classified as having culture-negative pneumonia, 1,940 (20.2%) as having pneumonia caused by antibiotic-susceptible bacteria, 2,991 (31.1%) as having pneumonia caused by potentially antibiotic-resistant bacteria, and 261 (2.7%) as having viral pneumonia. The 90-day hospital readmission rate for survivors (n = 7,637, 79.4%) was greatest for patients with pneumonia attributed to potentially antibiotic-resistant bacteria (11.4%) followed by viral pneumonia (8.3%), pneumonia attributed to antibiotic-susceptible bacteria (6.6%), and culture-negative pneumonia (5.8%) (P < .001). Multiple logistic regression analysis identified pneumonia attributed to potentially antibiotic-resistant bacteria to be independently associated with 90-day readmission (OR, 1.75; 95% CI, 1.56-1.97; P < .001). Other independent predictors of 90-day readmission were Charlson comorbidity score > 4, cirrhosis, and chronic kidney disease. Culture-negative pneumonia was independently associated with lower risk for 90-day readmission.
  
  
  CONCLUSIONS
  Readmission after hospitalization for pneumonia is relatively common and is related to pneumonia pathogen characterization. Pneumonia attributed to potentially antibiotic-resistant bacteria is associated with an increased risk for 90-day readmission, whereas culture-negative pneumonia is associated with lower risk for 90-day readmission.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO.
authors.forename: Adam
authors.initials: A
authors.lastname: Andruska
authors.affiliation: St. Louis College of Pharmacy, St. Louis, MO.
authors.forename: Scott T
authors.initials: ST
authors.lastname: Micek
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO; Institute for Advanced Research, Nagoya University, Nagoya, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Shindo
authors.affiliation: BJC Healthcare (Dr Hampton, Mr Colona, and Ms McCormick), Center for Clinical Excellence, St. Louis, MO.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Hampton
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO.
authors.forename: Brian
authors.initials: B
authors.lastname: Colona
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO.
authors.forename: Sandra
authors.initials: S
authors.lastname: McCormick
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO. Electronic address: mkollef@dom.wustl.edu.
authors.forename: Marin H
authors.initials: MH
authors.lastname: Kollef
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D024881:Drug Resistance, Bacterial; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010359:Patient Readmission / Q000706:statistics & numerical data*; D018410:Pneumonia, Bacterial / Q000382:microbiology* / Q000401:mortality / Q000628:therapy; D011024:Pneumonia, Viral / Q000401:mortality / Q000628:therapy / Q000821:virology*; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D055815:Young Adult