90-Day outcomes in patients with severe COVID-19 pneumonia treated with invasive mechanical ventilation.

Background: There are few reports detailing the prognostic factors of severe COVID-19 pneumonia requiring invasive ventilation. We investigated the long-term prognosis and evaluated which factors influenced outcomes in these patients.

Methods: Data was reviewed from severe adult COVID-19 cases admitted to our hospital and treated with mechanical ventilation between February 1, 2020, and October 30, 2021. On admission to our hospital, comorbidities and laboratory findings were collected from clinical records. Prognostic information for 90 days after diagnosis was also obtained from hospitals where patients were transferred after their conditions stabilized.

Results: Prognostic information was obtained in 133 patients, of which 106 were males (79.7 %). Of the 133 patients, 67 were discharged (51.5 %), 21 continued inpatient care (15.8 %), and 45 died (33.8 %). Age, Charlson Risk Index, and the number of patients on hemodialysis were significantly higher in the deceased group. There were no differences in therapeutic interventions between survivors and those who died except for a higher rate of muscle relaxant and vasopressor usage in the deceased group. Laboratory findings on admission showed significantly higher levels of BUN, creatinine, and serum Krebs von den Lungen 6 (KL-6), and significantly lower platelet counts, hemoglobin, and alanine aminotransferase in those who died. Multivariate analysis revealed that age, hemodialysis, lower platelet counts, and higher KL-6 were independent predictors for 90-day mortality.

Conclusions: Older age, hemodialysis, lower platelet counts and high KL-6 on admission were identified as independent predictors of 90-day mortality in patients with respiratory failure due to severe COVID-19 under invasive mechanical ventilation.