Background and Objective:
Although Healthcare associated infections (HAIs) pose per se extraordinary burden on Public Health, the impact of COVID-19 on healthcare is still on debate. Here, we aim to describe national trends of HAIs in Intensive Care Units (ICUs) from 2006 to 2021, and to compare clinical characteristics and outcomes of patients with or without COVID-19.

Methods:
We analyzed personal and clinical data of patients participating to the “Italian Nosocomial Infections Surveillance in Intensive Care Units” (SPIN-UTI) project, who were admitted to Italian ICUs for more than 48 hours. In addition, data about diagnosis, clinical conditions, therapy, treatments and outcomes of COVID-19 patients were collected.

Results:
On a total of 21523 patients from 2006 to 2021, 3485 (16.2%) presented at least one HAI. Overall, we observed an increasing trend for both the incidence of patients with HAI and the incidence density of HAIs (p-trend<0.001). Compared to the pre-pandemic period, the incidence density of HAIs increased of about 15% in 2020-21, with pneumoniae (PN) that mostly contributed to this increase (from approximately 9 to 13 infections per 1,000 patient days). Moreover, incidence of HAIs was higher in ICUs dedicated to COVID-19 patients (p<0.001), who showed a greater risk of HAIs and death than patients without COVID-19. Accordingly, the mortality in ICU increased and doubled during the pandemic (p-trend<0.001). Notably, co-infected patients had a higher mortality than in those with COVID-19 infection or HAI alone (66.2% and 39.9%, respectively) and those without any infection (23.2%).

Conclusion:
Our analysis provides useful insight on whether and how the COVID-19 pandemic influenced HAI incidence and death in Italian ICUs, highlighting the need of evaluating the long-term effect of the pandemic.