title: Clinical Utility of Testing for Legionella Pneumonia in Central Texas.
abstract: BACKGROUND
  Legionella pneumophila is an uncommon cause of community-acquired pneumonia in the south central region of the United States, and regular testing may not be cost effective in areas of low incidence.
  
  
  OBJECTIVE
  To evaluate the incidence of Legionella in central Texas and to determine the cost effectiveness of Legionella urinary antigen testing.
  
  
  METHODS
  We performed a single-center retrospective cohort study of patients admitted with pneumonia between January 2001 and December 2013. Patients were identified by Binax Legionella urinary antigen and International Classification of Disease, Ninth Revision codes. Demographic characteristics and clinical history of the confirmed Legionella pneumonia cases were obtained by chart review. Descriptive statistics were used to describe patient characteristics.
  
  
  RESULTS
  Over 12 years, 5,807 patients with 11,377 admissions for pneumonia were tested for Legionella urinary antigen. A positive Legionella urinary antigen was found in 17 patients. Cumulative incidence during the study period was 0.23%. Among the Legionella-positive patients, intensive care unit admission and median length of stay were 58.8% and 8.5 days, respectively. Most patients (64.7%) met American Thoracic Society criteria for severe pneumonia. All patients empirically received either a macrolide or fluoroquinolone covering Legionella. There were two in-hospital and three total 90-day deaths in those with a positive urinary antigen. The estimated cost of screening this population with Legionella urinary antigen was $214,438 over 13 years.
  
  
  CONCLUSIONS
  This study reveals the low incidence of Legionella pneumonia in central Texas. Use of guideline-concordant antibiotic treatment provides coverage for Legionella. We speculate that testing in a low-prevalence area would not influence outcomes or be cost effective.
authors.affiliation: 1 Division of Pulmonary, Critical Care and Sleep Medicine and.
authors.forename: Christopher
authors.identifier: http://orcid.org/0000-0002-1130-4267
authors.initials: C
authors.lastname: Henry
authors.affiliation: 1 Division of Pulmonary, Critical Care and Sleep Medicine and.
authors.forename: Carl
authors.identifier: http://orcid.org/0000-0002-2854-4195
authors.initials: C
authors.lastname: Boethel
authors.affiliation: 2 Center for Applied Health Research, Baylor Scott and White Health, Temple, Texas.
authors.forename: Laurel A
authors.identifier: http://orcid.org/0000-0002-9478-0209
authors.initials: LA
authors.lastname: Copeland
authors.affiliation: 1 Division of Pulmonary, Critical Care and Sleep Medicine and.
authors.forename: Shekhar
authors.identifier: http://orcid.org/0000-0001-6924-9494
authors.initials: S
authors.lastname: Ghamande
authors.affiliation: 1 Division of Pulmonary, Critical Care and Sleep Medicine and.
authors.forename: Alejandro C
authors.identifier: http://orcid.org/0000-0002-7245-2159
authors.initials: AC
authors.lastname: Arroliga
authors.affiliation: 1 Division of Pulmonary, Critical Care and Sleep Medicine and.
authors.forename: Heath D
authors.identifier: http://orcid.org/0000-0003-1065-3681
authors.initials: HD
authors.lastname: White
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D000942:Antigens, Bacterial / Q000652:urine; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology / Q000652:urine; D003362:Cost-Benefit Analysis; D005260:Female; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units; D016952:Legionella pneumophila / Q000276:immunology; D007877:Legionnaires' Disease / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology / Q000652:urine; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000175:diagnosis / Q000382:microbiology / Q000652:urine; D012189:Retrospective Studies; D013781:Texas / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D000942:Antigens, Bacterial
keywords: Legionella; Legionella urinary antigen; community-acquired pneumonia