Abstract
Background: Influenza-associated pulmonary aspergillosis (IAPA) is an
important complication of severe influenza with high morbidity and
mortality.
Methods: We conducted a retrospective multicenter study in tertiary
hospitals in Switzerland during 2017/18 and 2019/20 influenza seasons.
All adults with PCR-confirmed influenza infection and treatment on
intensive-care unit (ICU) for >24h were included. IAPA was
diagnosed according to previously published clinical, radiological and
microbiological criteria. We assessed risk factors for IAPA and
predictors for poor outcome which was a composite of in-hospital
mortality, ICU length of stay ≥7d, mechanical ventilation ≥7d or
extracorporeal membrane oxygenation.
Results: 158 patients (median age 64 years, 45% females) with influenza
were included, of which 17 (10.8%) had IAPA. Asthma was more common in
IAPA patients (17% vs. 4% in non-IAPA, p=0.05). Asthma (OR 12.0
[95% CI 2.1-67.2]) and days of mechanical ventilation (OR 1.1
[1.1 – 1.2]) were associated with IAPA. IAPA patients frequently
required organ supportive therapies including mechanical ventilation
(88% in IAPA vs. 53% in non-IAPA, p=0.001) and vasoactive support
(75% vs. 45%, p=0.03) and had more complications including ARDS (53%
vs. 26%, p=0.04), respiratory bacterial infections (65% vs. 37%,
p=0.04) and higher ICU-mortality (35% vs. 16.4%, p=0.05). IAPA (OR
28.8 [3.3–253.4]), influenza A (OR 3.3 [1.4-7.8]) and higher
SAPS II score (OR 1.07 [1.05—1.10]) were independent predictors of
poor outcome.
Interpretation: High clinical
suspicion, early diagnostics and therapy are indicated in IAPA because
of high morbidity and mortality. Asthma is likely an underappreciated
risk factor for IAPA.