Clinical and laboratory predictors at ICU admission affecting course of illness and mortality rates in a tertiary COVID-19 center.

Retrospective single-center study from electronic records, so unmeasured confounding and missing data could affect the results. Only the most severe patients were admitted to the ICU because many high-flow oxygen patients were managed in specialized wards, so the findings may not apply to less severe ICU patients. Many patients came from other institutions or palliative facilities, which could have increased mortality and selection bias. Patients re-transferred to other hospitals after negative PCR tests were not followed long term, so later outcomes are incomplete. Treatments such as corticosteroids, anticoagulation, antiplatelet therapy, antivirals and immunomodulators were not recorded electronically, so their effects could not be analysed. The study is observational, so it cannot prove that any factor or intervention caused death; some adjusted associations, such as arterial hypertension and CRP, are difficult to interpret. Some biomarker and complication associations were inconsistent between analyses, making them hard to interpret.

The authors declared no known competing financial interests or personal relationships that could have influenced the work.

Do not conclude that invasive mechanical ventilation caused death. Patients who needed ventilation were already much sicker, and this retrospective observational study cannot separate the effect of treatment from severity.