This study, published on JAMA, evaluates the independent risk factors associated with mortality of patients with COVID-19 requiring treatment in ICUs in the Lombardy region of Italy.

This retrospective, observational cohort study includes 3988 consecutive critically ill patients with laboratory-confirmed COVID-19 referred for
ICU admission to the coordinating center of the COVID-19 Lombardy ICU Network from February 20 to April 22, 2020.

Infection with severe acute respiratory syndrome coronavirus 2 was confirmed by real-time reverse transcriptase– polymerase chain reaction assay of nasopharyngeal swabs.

Follow-up was completed on May 30, 2020.
Main outcomes are time to death in days from ICU admission to hospital
discharge.

Of the 3988 patients included in this cohort study, the median age was 63
years; 3188 were men, and 1998 of 3300 had at least 1 comorbidity.

At ICU admission, 2929 patients (87.3%) required invasive mechanical ventilation (IMV).
The median follow-up was 44 days; median time from symptoms onset to ICU admission was 10 days; median length of ICU stay was 12 days and median length of IMV was 10 days. Cumulative observation time was 164 305 patient-days.

Hospital and ICU mortality rates were 12 and 27 per 1000 patients-days,
respectively. In the subgroup of the first 1715 patients, as of May 30, 2020, 865 (50.4%) had been discharged from the ICU,

836 (48.7%) had died in the ICU, and 14 (0.8%) were still in the ICU; overall, 915 patients (53.4%) died in the hospital.

Independent risk factors associated with mortality included older age (hazard ratio [HR], 1.75; 95% CI, 1.60-1.92), male sex (HR,
1.57; 95% CI, 1.31-1.88), high fraction of inspired oxygen (FiO2) (HR, 1.14; 95% CI, 1.10-1.19), high positive end-expiratory pressure (HR, 1.04; 95% CI, 1.01-1.06) or low PaO2:FiO2 ratio (HR, 0.80; 95% CI, 0.74-0.87) on ICU admission, and history of chronic obstructive pulmonary disease (HR, 1.68; 95% CI, 1.28-2.19), hypercholesterolemia (HR, 1.25; 95% CI, 1.02-1.52), and
type 2 diabetes (HR, 1.18; 95% CI, 1.01-1.39). No medication was independently associated with mortality (angiotensin-converting enzyme inhibitors HR, 1.17; 95% CI, 0.97-1.42; angiotensin receptor blockers HR, 1.05; 95% CI, 0.85-1.29).

In this retrospective cohort study of critically ill patients
admitted to ICUs in Lombardy, Italy, with laboratory-confirmed COVID-19, most patients required IMV. The mortality rate and absolute mortality are high.