Mortality rates are similar for patients receiving mechanical ventilation (MV) for severe COVID-19 pneumonia and those receiving MV due to pneumonia from other causes, according to study findings published in the Journal of the American Medical Association Network Open.
Investigators aimed to compare the outcomes of patients receiving MV due to COVID-19 pneumonia vs non-COVID-19 pneumonia. The primary endpoint was 90-day in-hospital mortality. Secondary endpoints included time to mechanical ventilation liberation, static respiratory system compliance, hospital length of stay, and ventilatory ratio.
This retrospective cohort study was conducted at 5 hospitals in the Johns Hopkins Healthcare System in Maryland and Washington, DC. The study involved adult patients hospitalized with pneumonia due to COVID-19 between March 2020 and June 2021 and patients hospitalized with pneumonia due to other causes between July 2016 and December 2019. All patients studied had required MV in the first 2 weeks of hospitalization. Patients with COVID-19 tested positive for SARS-CoV-2 by polymerase chain reaction. Patients with non-COVID-19 pneumonia were identified using ICD-10 codes. All patients with ventilator-associated pneumonia or with a tracheostomy on admission were excluded.
Investigators included 719 patients with severe COVID-19 pneumonia (mean [SD] age 61.8 [15.3] years; 38.5% female; 35% White; 64% minoritized Non-White/Non-Hispanic) and 1127 patients with severe non-COVID-19 pneumonia (mean age 60.9 [15.8] years; 48.0% female; 58% White, 41% minoritized Non-White/Non-Hispanic).
Unadjusted analysis showed patients with COVID-19 pneumonia had higher 90-day mortality (odds ratio [OR], 1.21; 95% CI, 1.04-1.41), longer time on mechanical ventilation (subdistribution hazard ratio, 0.72; 95% CI, 0.63-0.81), and lower static respiratory compliance (32.0 vs 28.4mL/kg PBW/cmH2O; P <.001) vs patients with non-COVID-19 pneumonia. Patients who discontinued mechanical ventilation but died during hospitalization did not contribute to analyses of time on mechanical ventilation but were counted as deaths.
Mechanically ventilated patients with severe COVID-19 pneumonia had similar mortality rates as patients with other causes of severe pneumonia but longer times to liberation from mechanical ventilation.
Prior to matching, investigators noted that patients with COVID-19 were more likely to be men and to be categorized as minoritized Non-White/Non-Hispanic; they were also more likely to have diabetes, a lower Sequential Organ Failure Assessment score, higher mean body mass index, and a lower mean ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FiO2). Those with COVID-19 were intubated a mean 4.1 days (95% CI, 3.8-4.4) after admission vs 3.4 days (95% CI, 3.1-3.6) for patients with non-COVID-19 pneumonia (P <.001).
Propensity score-matched analyses revealed patients with COVID-19 pneumonia were equally likely to die within 90 days as patients with non-COVID-19 pneumonia (OR, 1.04; 95% CI, 0.81-1.35; P =.85). Patients with COVID-19 pneumonia vs non-COVID-19 pneumonia had similar respiratory system compliance (mean difference, 1.82mL/cmH2O; 95% CI, -1.53 to 5.17mL/cmH2O; P =.28) and similar ventilatory ratio (mean difference, -0.05; 95% CI, -0.22 to 0.11; P =.52) but lower rates of liberation from mechanical ventilation (subdistribution hazard ratio, 0.81; 95% CI, 0.65-1.00).
Investigators noted patients with COVID-19 pneumonia had lower (but not statistically significant) rates of hospital discharge alive at 90 days (subdistribution hazard ratio, 0.83; 95% CI, 0.68-1.01) vs patients with non-COVID-19 pneumonia.
Significant study limitations include the single health-system design, missing data, and the identification of patients with non-COVID-19 pneumonia via ICD-10 codes instead of microbiologic data. Additional limitations include unmeasured or residual confounding, unaccounted-for patient/mechanical ventilation management, and failure to include non-COVID-19 pneumonia patients between March 2020 and June 2021.
“Mechanically ventilated patients with severe COVID-19 pneumonia had similar mortality rates as patients with other causes of severe pneumonia but longer times to liberation from mechanical ventilation,” the investigators concluded. They further added, “We did not find convincing evidence of different physiologic phenotypes in patients with COVID-19 pneumonia.”