Invasive aspergillosis in critically ill patients: analysis of risk factors for acquisition and mortality.

OBJECTIVE: To investigate outcome in patients who develop invasive aspergillosis in the ICU, and to evaluate whether specific risk factors for the acquisition of invasive aspergillosis are associated with mortality.
DESIGN: Retrospective cohort study (07/1997-12/1999) with screening of 8988 admissions.
SETTING: 54-bed ICU of the 1060-bed Ghent University Hospital. PATIENTS: 38 ICU patients with invasive aspergillosis. Invasive aspergillosis was defined as proven by positive histology and tissue culture and as probable by a combination of clinical suspicion as well as microbiological and radiological data. Seventeen patients had risk factors (neutropenia, haematological malignancy, immunosuppressive therapy). In the other 21 apparently immunocompetent patients, invasive aspergillosis was a complication following ARDS, COPD, pneumonia, acute liver failure, burns, severe bacterial infection and malnutrition. MEASUREMENTS: Population characteristics and outcome were compared for patients with and without risk factors for the acquisition of invasive aspergillosis.
RESULTS: Patients with risk factors had higher APACHE II scores. No difference was found between patients with and without risk factors in in-hospital mortality (82% vs. 71%; p=0.431). In patients with specific risk factors, the observed mortality was not different from the mortality as expected on basis of the APACHE II (p=0.940). In patients without risk factors the observed mortality exceeded the expected mortality (p<0.001).
CONCLUSION: The incidence of invasive aspergillosis in this series is 4/1000 admissions. No difference in mortality was found between patients with and without risk factors for the acquisition of invasive aspergillosis. Yet, the prognosis of the patients without risk factors seems to alter more seriously by the development of this infection.