Understanding the factors affecting COVID-19 mortality in Italy: Does a relationship exist with a sharp increase in Intensive Care Unit admissions?

Background: The present study aims to explore if a relationship exists between the immediate sharp increase in Intensive Care Unit (ICU) admissions and the mortality rates in Italy. Methods: Official epidemiological data on COVID-19 were employed. The forward lagged (0, 3, 7, 14 days) daily variations in the number of deaths according to the number of days after the outbreak started and the daily increases in ICU admissions were estimated. Results: A direct relationship between the sharp increase of ICU admissions and mortality rates has been shown. Furthermore, the analysis of the forward lagged daily variations in the number of deaths showed that an increase in the daily number of ICU admissions resulted in significantly higher mortality after 3, 7, and 14 days. The most pronounced effect was detected after 7 days, with 250 deaths (95% C.I. 108.1-392.8) for the highest increase in the ICU admissions -from 100 to 200- Conclusions: These results would serve as a warning for the scientific community and the health care decision-makers to prevent a quick and out-of-control saturation of the ICU beds in case of a relapse of the COVID-19 outbreak.