title: Reporting catheter-associated urinary tract infections: denominator matters.
abstract: OBJECTIVE
  To evaluate two different methods of measuring catheter-associated urinary tract infection (CAUTI) rates in the setting of a quality improvement initiative aimed at reducing device utilization.
  
  
  METHODS
  Comparison of CAUTI measurements in the context of a before-after trial of acute care adult admissions to a multicentered healthcare system.
  
  
  METHODS
  CAUTIs were identified with an automated surveillance system, and device-days were measured through an electronic health record. Traditional surveillance measures of CAUTI rates per 1,000 device-days (R1) were compared with CAUTI rates per 10,000 patient-days (R2) before (T1) and after (T2) an intervention aimed at reducing catheter utilization.
  
  
  RESULTS
  The device-utilization ratio declined from 0.36 to 0.28 between T1 and T2 (P = .001), while infection rates were significantly lower when measured by R2 (28.2 vs 23.2, P = .02). When measured by R1, however, infection rates trended upward by 6% (7.79 vs. 8.28, P = .47), and at the nursing unit level, reduction in device utilization was significantly associated with increases in infection rate.
  
  
  CONCLUSIONS
  The widely accepted practice of using device-days as a method of risk adjustment to calculate device-associated infection rates may mask the impact of a successful quality improvement program and reward programs not actively engaged in reducing device usage.
authors.affiliation: Department of Infection Control, NorthShore University HealthSystem, Evanston, Illinois 60201, USA. mwright@northshore.org
authors.forename: Marc-Oliver
authors.initials: MO
authors.lastname: Wright
authors.forename: Maureen
authors.initials: M
authors.lastname: Kharasch
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Beaumont
authors.forename: Lance R
authors.initials: LR
authors.lastname: Peterson
authors.forename: Ari
authors.initials: A
authors.lastname: Robicsek
mesh_terms: D000328:Adult; D055499:Catheter-Related Infections / Q000453:epidemiology*; D002408:Catheters, Indwelling / Q000706:statistics & numerical data*; D003428:Cross Infection / Q000453:epidemiology*; D003627:Data Interpretation, Statistical; D004812:Epidemiologic Methods; D006785:Hospitals, University; D006801:Humans; D058996:Quality Improvement / Q000706:statistics & numerical data*; D020379:Risk Adjustment / Q000379:methods; D014546:Urinary Catheterization / Q000706:statistics & numerical data; D014552:Urinary Tract Infections / Q000453:epidemiology*