COVID-19 can manifest as a viral induced hyperinflammation with multi-organ involvement. Such patients often experience rapid deterioration and need for mechanical ventilation. Currently, no prospectively validated biomarker of impending respiratory failure is available.
We aimed to identify and prospectively validate biomarkers that allow the identification of patients in need of impending mechanical ventilation.
Patients with COVID-19 hospitalized from February 29 th to April 09 th, 2020 were analyzed for baseline clinical and laboratory findings at admission and during the disease. Data from 89 evaluable patients were available for the purpose of analysis comprising an initial evaluation cohort (n=40) followed by a temporally separated validation cohort (n=49).
We identified markers of inflammation, LDH and creatinine as most predictive variables of respiratory failure in the evaluation cohort. Maximal interleukin-6 (IL-6) levels before intubation showed the strongest association with the need of mechanical ventilation followed by maximal CRP. Respective AUC values for IL-6 and CRP in the evaluation cohort were 0.97 and 0.86 and similar in the validation cohort 0.90 and 0.83. The calculated optimal cutoff values in the course of disease from the evaluation cohort (IL-6> 80 pg/ml and CRP> 97 mg/l) both correctly classified 80% of patients in the validation cohort regarding their risk of respiratory failure.
We studied laboratory parameters as predictors of impending respiratory failure in COVID-19. Maximum levels of interleukin-6 over the course of disease, followed by CRP, were the best predictors of respiratory failure in two separate cohorts.