title: Assessment of Clostridium difficile-associated disease surveillance definitions, North Carolina, 2005.
abstract: OBJECTIVE
  To determine the timing of community-onset Clostridium difficile-associated disease (CDAD) relative to the patient's last healthcare facility discharge, the association of postdischarge cases with healthcare facility-onset cases, and the influence of postdischarge cases on overall rates and interhospital comparison of rates of CDAD.
  
  
  METHODS
  Retrospective cohort study for the period January 1, 2005, through December 31, 2005.
  
  
  METHODS
  Catchment areas of 6 acute care hospitals in North Carolina.
  
  
  METHODS
  We reviewed medical and laboratory records to determine the date of symptom onset, the dates of hospitalization, and stool C. difficile toxin assay results for patients with CDAD who had diarrhea and positive toxin-assay results. Cases were classified as healthcare facility-onset if they were diagnosed more than 48 hours after admission. Cases were defined as community-onset if they were diagnosed in the community or within 48 hours after admission, and were also classified on the basis of the time since the last discharge: if within 4 weeks, community-onset, healthcare facility-associated (CO-HCFA); if 4-12 weeks, indeterminate exposure; and if more than 12 weeks, community-associated. Pearson's correlation coefficient was used to assess the association between monthly rates of healthcare facility-onset, healthcare facility-associated (HO-HCFA) cases and CO-HCFA cases. We performed interhospital rate comparisons using HO-HCFA cases only and using both HO-HCFA and CO-HCFA cases.
  
  
  RESULTS
  Of 1046 CDAD cases, 442 (42%) were HO-HCFA cases and 604 (58%) were community-onset cases. Of the 604 community-onset cases, 94 (15%) were CO-HCFA, 40 (7%) were of indeterminate exposure, and 208 (34%) community-associated. A modest correlation was found between monthly rates of HO-HCFA cases and CO-HCFA cases across the 6 hospitals (r = 0.63, P < .001). Interhospital rankings changed for 6 of 11 months if CO-HCFA cases were included.
  
  
  CONCLUSIONS
  A substantial proportion of community-onset cases of CDAD occur less than 4 weeks after discharge from a healthcare facility, and inclusion of CO-HCFA cases influences interhospital comparisons. Our findings support the use of a proposed definition of healthcare facility-associated CDAD that includes cases that occur within 4 weeks after discharge.
authors.affiliation: Division of Healthcare Quality Promotion, National Center for Preparedness, Detection, and Control of Infectious Diseases, Centers for Disease Control and Prevention, Department of Health and Human Services, Atlanta, Georgia 30333, USA.
authors.forename: Preeta K
authors.initials: PK
authors.lastname: Kutty
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Benoit
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Woods
authors.forename: Arlene C
authors.initials: AC
authors.lastname: Sena
authors.forename: Susanna
authors.initials: S
authors.lastname: Naggie
authors.forename: Joyce
authors.initials: J
authors.lastname: Frederick
authors.forename: John
authors.initials: J
authors.lastname: Engemann
authors.forename: Sharon
authors.initials: S
authors.lastname: Evans
authors.forename: Brian C
authors.initials: BC
authors.lastname: Pien
authors.forename: Shailendra N
authors.initials: SN
authors.lastname: Banerjee
authors.forename: Jeffery
authors.initials: J
authors.lastname: Engel
authors.forename: L Clifford
authors.initials: LC
authors.lastname: McDonald
mesh_terms: D016360:Clostridioides difficile / Q000302:isolation & purification; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology; D003625:Data Collection / Q000379:methods*; D004761:Enterocolitis, Pseudomembranous / Q000453:epidemiology* / Q000382:microbiology; D005243:Feces / Q000382:microbiology; D006761:Hospitals; D006801:Humans; D009657:North Carolina / Q000453:epidemiology; D010351:Patient Discharge; D012189:Retrospective Studies; D018571:Sentinel Surveillance; D013997:Time Factors