Secondary invasive fungal infection in hospitalised patients with COVID-19 in the United States.

Background: Invasive fungal infections (IFIs) have been identified as a complication in patients with Coronavirus disease 2019 (COVID-19). To date, there are few US studies examining the excess humanistic and economic burden of IFIs on hospitalised COVID-19 patients.

Objectives: This study investigated the incidence, risk factors, clinical and economic burden of IFIs in patients hospitalised with COVID-19 in the United States.

Patients/methods: Data from adult patients hospitalised with COVID-19 during 01 April 2020-31 March 2021 were extracted retrospectively from the Premier Healthcare Database. IFI was defined either by diagnosis or microbiology findings plus systemic antifungal use. Disease burden attributable to IFI was estimated using time-dependent propensity score matching.

Results: Overall, 515,391 COVID-19 patients were included (male 51.7%, median age: 66 years); IFI incidence was 0.35/1000 patient-days. Most patients did not have traditional host factors for IFI such as hematologic malignancies; COVID-19 treatments including mechanical ventilation and systemic corticosteroid use were identified as risk factors. Excess mortality attributable to IFI was estimated at 18.4%, and attributable excess hospital costs were $16,100.

Conclusions: Invasive fungal infection incidence was lower than previously reported, possibly due to a conservative definition of IFI. Typical COVID-19 treatments were among the risk factors identified. Furthermore, diagnosis of IFIs in COVID-19 patients may be complicated because of the several non-specific shared symptoms, leading to underestimation of the true incidence rate. The healthcare burden of IFIs was significant among COVID-19 patients, including higher mortality and greater cost.