Problematic Dichotomization of Risk for Intensive Care Unit (ICU)-Acquired Invasive Candidiasis: Results Using a Risk-Predictive Model to Categorize 3 Levels of Risk From a Multicenter Prospective Cohort of Australian ICU Patients.
BACKGROUND
Delayed antifungal therapy for invasive candidiasis (IC) contributes to poor outcomes. Predictive risk models may allow targeted antifungal prophylaxis to those at greatest risk.


METHODS
A prospective cohort study of 6685 consecutive nonneutropenic patients admitted to 7 Australian intensive care units (ICUs) for ≥72 hours was performed. Clinical risk factors for IC occurring prior to and following ICU admission, colonization with Candida species on surveillance cultures from 3 sites assessed twice weekly, and the occurrence of IC ≥72 hours following ICU admission or ≤72 hours following ICU discharge were measured. From these parameters, a risk-predictive model for the development of ICU-acquired IC was then derived.


RESULTS
Ninety-six patients (1.43%) developed ICU-acquired IC. A simple summation risk-predictive model using the 10 independently significant variables associated with IC demonstrated overall moderate accuracy (area under the receiver operating characteristic curve = 0.82). No single threshold score could categorize patients into clinically useful high- and low-risk groups. However, using 2 threshold scores, 3 patient cohorts could be identified: those at high risk (score ≥6, 4.8% of total cohort, positive predictive value [PPV] 11.7%), those at low risk (score ≤2, 43.1% of total cohort, PPV 0.24%), and those at intermediate risk (score 3-5, 52.1% of total cohort, PPV 1.46%).


CONCLUSIONS
Dichotomization of ICU patients into high- and low-risk groups for IC risk is problematic. Categorizing patients into high-, intermediate-, and low-risk groups may more efficiently target early antifungal strategies and utilization of newer diagnostic tests.
Infection Management Services, Princess Alexandra Hospital.|School of Medicine, University of Queensland.
E Geoffrey
EG
Playford
Department of Intensive Care, Royal Brisbane and Women's Hospital.|University of Queensland, Brisbane.
Jeffrey
J
Lipman
Psychology Department, Macquarie University, Sydney.
Michael
M
Jones
Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research.
Anna F
AF
Lau
Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research.
Masrura
M
Kabir
Centre for Infectious Diseases and Microbiology Laboratory Services, Institute for Clinical Pathology and Medical Research, Westmead Hospital.|Sydney Medical School, University of Sydney.
Sharon C-A
SC
Chen
Department of Microbiology and Infectious Diseases, St Vincent's Hospital.
Deborah J
DJ
Marriott
Department of Intensive Care Medicine, Nepean Hospital, University of Sydney.
Ian
I
Seppelt
Department of Microbiology and Infectious Diseases.
Thomas
T
Gottlieb
Department of Intensive Care Medicine, Concord Hospital.
Winston
W
Cheung
Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research.|Department of Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney.
Jonathan R
JR
Iredell
Department of Victorian Infectious Diseases Service, Royal Melbourne Hospital, University of Melbourne, Australia.
Emma S
ES
McBryde
Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research.|Department of Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney.
Tania C
TC
Sorrell
D000328:Adult; D000368:Aged; D000935:Antifungal Agents / Q000627:therapeutic use; D001315:Australia / Q000453:epidemiology; D002175:Candida / Q000302:isolation & purification; D002177:Candidiasis / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control; D058365:Candidiasis, Invasive / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D015331:Cohort Studies; D016638:Critical Illness; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D018570:Risk Assessment; D012307:Risk Factors
D000935:Antifungal Agents
candidemia; critical care; invasive candidiasis; prophylaxis; risk prediction