Clinical characteristics and outcomes of influenza-associated pulmonary aspergillosis among critically ill patients: a systematic review and meta-analysis

Invasive pulmonary aspergillosis is increasingly identified as a complication of influenza, termed 'influenza-associated pulmonary aspergillosis' (IAPA).To assess the morbidity and mortality of critically ill influenza patients with and without IAPA.PubMed, Cochrane Library, Scopus and Embase databases were searched for studies containing comparative data of critically ill influenza patients with IAPA. Primary outcomes were all-cause in-hospital and intensive care unit (ICU) mortality. Secondary outcomes were clinical characteristics; duration of invasive mechanical ventilation (IMV); ICU and hospital length of stay (LOS); and requirement for vasopressor, renal replacement therapy (RRT) and extracorporeal membrane oxygenation (ECMO).The incidence of IAPA was 28.8% in 853 critically ill influenza patients, with an overall mortality rate of 33.4%. No differences in age and comorbidities were observed. Patients with IAPA were predominantly male and received chronic corticosteroids. In-hospital (49.2% vs 27.0%; P=0.002) and ICU (46.8% vs 20.8%; P<0.001) mortality rates were higher among patients with IAPA than in patients without IAPA. A greater proportion of patients with IAPA required IMV, and had a prolonged IMV duration (mean 17.3 vs 10.5 days; P<0.001), ICU LOS (mean 26.8 vs 12.8 days; P=0.001) and hospital LOS (mean 38.7 vs 27.0 days; P=0.003). Patients with IAPA had greater disease severity and were significantly more likely to require vasopressor (76.4% vs 57.9%; P<0.001), RRT (45.7% vs 19.1%; P<0.001) and ECMO (25.9% vs 12.8%; P=0.004) support compared with patients without IAPA.A diagnosis of IAPA in critically ill patients is associated with greater morbidity and mortality. Early recognition and more research are needed to determine better diagnostic and treatment strategies.