Severe influenza is an independent risk factor for invasive pulmonary aspergillosis with an accompanying increased mortality in the ICU, according to a multicenter retrospective cohort study at seven tertiary centers in Belgium and the Netherlands.
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Data was collected from criteria-meeting adult patients admitted to the ICU for more than 24 hours with acute respiratory failure during the 2009-2016 influenza seasons. The included cohort of 432 patients was composed of 56% men and had a median age of 59 years; all participants were diagnosed as having severe type A or type B influenza infection according to positive airway RT-PCR results.
The full cohort was subcategorized into 117 immunocompromised and 315 as nonimmunocompromised individuals using criteria established by the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study group (EORTC/MSG) . To assess influenza as an independent variable in the development of invasive pulmonary aspergillosis, the 315 nonimmunocompromised influenza positive individuals were compared to an influenza-negative control group of 315 nonimmunocompromised patients admitted to the ICU that presented similar respiratory insufficiency symptoms with community-acquired pneumonia.
Determination of other independent risk factors for incidence of invasive pulmonary aspergillosis was achieved by multivariate analysis of factors such as sex, diabetes status, prednisone use, age, and acute physiology and chronic health evaluation (APACHE) II score. The mean APACHE II score was 22, with the majority of patients requiring intubation for mechanical ventilation for a median duration of 11 days.
Influenza is not considered a host factor for invasive pulmonary aspergillosis and will often miss being diagnosed when using strict interpretation of the current EORTC/MSG or AspICU algorithm criteria, according to the researchers. Consequently for patients with influenza and the noninfluenza control group with community-acquired pneumonia, the definition of invasive pulmonary aspergillosis was modified from the AspICU algorithm. Stringent mycological criteria, including bronchoaveolar lavage (BAL) culture, a positive Aspergillus culture, positive galactomannan test, and/or positive serum galactomannan tests, provided supporting diagnostics for an invasive pulmonary aspergillosis determination.