Influenza-associated aspergillosis is uncommon in US, study shows
Click Here to Manage Email Alerts
Influenza-associated aspergillosis, or IAA, is uncommon in ICU patients in the United States, with a prevalence of 0.3%, according to an analysis of health insurance claims data.
Researchers said the low frequency of IAA in hospitalized patients might reflect underdiagnosis.
“We had heard from our European colleagues that severe influenza is an emerging risk factor for invasive aspergillosis (IA). IA is a sometimes-fatal mold infection that commonly affects patients who are immunocompromised from conditions like organ or stem cell transplant or cancer, but influenza is not typically considered an immunocompromising condition,” Mitsuru Toda, MS, PhD, an epidemiologist in the CDC’s Mycotic Diseases Branch, told Healio.
For example, Toda mentioned a study from 2018 that showed that up to 19% of ICU patients with influenza in Belgium and the Netherlands had evidence of IA, and half of these patients did not have any known immunocompromising conditions.
Toda added, “Only a few cases of IA/influenza coinfection have been reported in the United States, so we wanted to study a large population to try to understand if this phenomenon is emerging in the U.S., too.”
Using data from the IBM MarketScan Commercial Claims and Encounters database, Toda and colleagues assessed the proportion of ICU patients who developed IA after influenza or non-influenza viral respiratory infection between 2013 and 2018.
Among approximately 64 million patients with any health care encounter during that time, around 7 million patients were hospitalized. Of those hospitalized patients, 948 (0.01%) had IA codes recorded. Among the approximate 1.5 million ICU patients included in the study, 341 (0.02%) had IA without influenza or another viral respiratory infection.
Researchers restricted the study to a 3-month window and found that IA occurred in 25 (0.3%) of 7,672 ICU patients with influenza and in 45 (0.3%) of 14,673 ICU patients with non-influenza viral respiratory infection. After restricting the window to 2 weeks, they found that IA occurred in 15 (0.2%) of 7,672 ICU patients with influenza and in 37 (0.3%) of 14,673 ICU patients with non-influenza viral respiratory infection.
Additionally, the median age range — 56 to 59 years — was similar among patients with IAA, non-influenza viral respiratory infection-associated aspergillosis and IA. Chronic obstructive pulmonary disease was the most common (51% to 60%) underlying condition in all three groups.
“Although relatively few patients were identified with influenza and aspergillosis, this number was substantially more than the dozen or so U.S. cases reported in the literature,” Toda said, adding that although researchers did not find many ICU patients with both influenza and aspergillosis, it does not mean that influenza-associated aspergillosis is not a problem in the U.S., given that Aspergillus testing is limited.
“Given other evidence that testing for Aspergillus in U.S. ICU patients with influenza is uncommon, prospective studies are needed to examine how common influenza-associated aspergillosis truly is in the United States,” Toda said.
Collapse
Read more about
Click Here to Manage Email Alerts