title: Concordance of the SHEA-IDSA severity classification for Clostridium difficile infection and the ATLAS bedside scoring system in hospitalized adult patients.
abstract: OBJECTIVE
  The Society for Healthcare Epidemiology of America and Infectious Diseases Society of America (SHEA-IDSA) guidelines for the treatment of Clostridium difficile infection (CDI) recommend initial treatment of CDI based on disease severity. This severity definition has not been validated or evaluated based on clinical outcomes. The ATLAS scoring system is a validated tool useful in predicting treatment response and mortality in CDI. The main purpose of this study is to evaluate the concordance of the ATLAS scoring system and the SHEA-IDSA staging for CDI severity.
  
  
  METHODS
  This was a retrospective study which included hospitalized patients with confirmed CDI. Bivariate analyses compared baseline demographics and clinical information between patients with nonsevere and severe CDI based on the SHEA-IDSA criteria for CDI severity. Kappa scores were calculated to compare the concordance of the two scoring systems in defining CDI severity. Sensitivity and specificity of the ATLAS scoring system to determine CDI severity were calculated using the SHEA-IDSA criteria as the reference standard.
  
  
  RESULTS
  Sixty-four patients met inclusion criteria. Of those, 62.5% were classified as mild to moderate CDI, 25% were severe, uncomplicated, and 12.5% were severe, complicated based on SHEA-IDSA criteria. In the bivariate analyses, ATLAS score breakpoints of ≥ 4, ≥ 5, and ≥ 6 revealed moderate agreement with the SHEA-IDSA classification for severity. The sensitivities and specificities for ATLAS scores in predicting CDI severity ranged from 58.3 to 87.5, and 67.5-87.5%, respectively.
  
  
  CONCLUSIONS
  The ATLAS score may be useful in evaluating CDI severity and determining drug therapy selection.
authors.affiliation: Department of Pharmaceutical Services, Vanderbilt University Medical Center, Nashville, TN, USA, diana.l.wells@vanderbilt.edu.
authors.forename: D W
authors.initials: DW
authors.lastname: Mulherin
authors.forename: A M
authors.initials: AM
authors.lastname: Hutchison
authors.forename: G J
authors.initials: GJ
authors.lastname: Thomas
authors.forename: R A
authors.initials: RA
authors.lastname: Hansen
authors.forename: D T
authors.initials: DT
authors.lastname: Childress
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016360:Clostridioides difficile / Q000302:isolation & purification*; D003015:Clostridium Infections / Q000145:classification* / Q000175:diagnosis*; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index