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Baseline characteristics and outcomes of 1591 patients infected with SARS-CoV-2 admitted to ICUs of the Lombardy Region, Italy

Our take —

This study, a large case series from Lombardy, Italy during the early phase of the epidemic in Europe, provides strong evidence for the higher prevalence of comorbidities, including hypertension and cardiovascular dysfunction, among those progressing to severe disease. Critically-ill COVID-19 patients were more likely to be male and of older age, and the vast majority required mechanical ventilation.

Study design

Case Series

Study population and setting

The study consisted of 1591 patients with laboratory-confirmed COVID-19 disease admitted to an ICU within the Lombardy ICU Network, established in response to the outbreak, and treated between February 20 and March 18, 2020. Final follow-up was on March 25, 2020.

Summary of Main Findings

82% of the patients were male and the median age was 63 years. Sixty-eight percent had at least 1 comorbidity upon admission: 49% had hypertension, 21% had cardiovascular disease, and 18% had hypercholesterolemia. Among those requiring respiratory support, 88% received mechanical ventilation and 11% received noninvasive ventilation. By the end of follow-up, 26% (n=405) had died, 16% (n=256) had been discharged, and 58% (n=920) remained in the ICU. Mortality was higher among patients older than 63 (36%) than those 63 years or younger (11%). The median length of stay in the ICU was 8 days among patients who were discharged, 7 days among those who died, and 10 days among those still in the ICU at end of follow-up. The prevalence of hypertension among those who died was 23% higher relative to those who were discharged (p<0.001).

Study Strengths

This is a large case series of critically-ill patients with laboratory-confirmed COVID-19 disease admitted to a network of ICUs, thus permitting more robust estimates of symptom prevalence, disease progression, and outcomes.


Asymptomatic and milder cases are not represented. Many patients remained hospitalized at the time of publication; therefore, data on outcomes were incomplete and it is possible the disease trajectories of these patients may differ from those who had an observable outcome (either death or discharge). Given the descriptive nature of the study, no formal hypotheses were tested, nor were analyses adjusted for any potential confounders.

Value added

This is the largest case series of critically-ill COVID-19 patients in the Lombardy region of Italy (through April 6,2020). Authors present key data on outcomes and ventilator requirements in a high-income setting.