Hospitalised COVID-19 outcomes are predicted by hypoxaemia and pneumonia phenotype irrespective of the timing of their emergence

Brittany Salter; Bianca DeBenedictis; Laura Spatafora; Jessica Kapralik; Candice Luo; Steven Qiu; Laura Dawson; Mats Junek; Tyler Pitre; Aaron Jones; Marla Beauchamp; Rebecca Kruisselbrink; MyLinh Duong; Andrew P Costa; Jennifer Ly Tsang; Terence Ho

doi:10.1136/bmjopen-2022-062453

Hospitalised COVID-19 outcomes are predicted by hypoxaemia and pneumonia phenotype irrespective of the timing of their emergence

BMJ Open. 2022 Dec 29;12(12):e062453. doi: 10.1136/bmjopen-2022-062453.

Authors

Brittany Salter¹, Bianca DeBenedictis², Laura Spatafora², Jessica Kapralik², Candice Luo², Steven Qiu², Laura Dawson², Mats Junek³, Tyler Pitre², Aaron Jones⁴, Marla Beauchamp⁵, Rebecca Kruisselbrink², MyLinh Duong⁶, Andrew P Costa⁷, Jennifer Ly Tsang^{2

8}, Terence Ho^{2

6}

Affiliations

¹ Department of Medicine, McMaster University, Hamilton, Ontario, Canada brittany.salter@medportal.ca.
² Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
³ Department of Rheumatology, McMaster University, Hamilton, Ontario, Canada.
⁴ Department of Health Research Methods, Evidence, and Impact, McMaster University Faculty of Health Sciences, Hamilton, Ontario, Canada.
⁵ School of Rehabilitation Science, McMaster University, Hamilton, Ontario, Canada.
⁶ Respirology, McMaster University, Hamilton, Ontario, Canada.
⁷ McMaster University, Hamilton, Ontario, Canada.
⁸ Medicine, Niagara Health System - Saint Catharines Site, Saint Catharines, Ontario, Canada.

Abstract

Despite the known clinical importance of hypoxemia and pneumonia, there is a paucity of evidence for these variables with respect to risk of mortality and short-term outcomes among those hospitalised with COVID-19.

Objective: Describe the prevalence and clinical course of patients hospitalised with COVID-19 based on oxygenation and pneumonia status at presentation and determine the incidence of emergent hypoxaemia or radiographic pneumonia during admission.

Methods: A retrospective study was conducted using a Canadian regional registry. Patients were stratified according to hypoxaemia/pneumonia phenotype and prevalence. Clinical parameters were compared between phenotypes using χ² and one-way Analysis of variance (ANOVA). Cox analysis estimated adjusted Hazard Ratios (HR) for associations between disease outcomes and phenotypes.

Results: At emergency department (ED) admission, the prevalence of pneumonia and hypoxaemia was 43% and 50%, respectively, and when stratified to phenotypes: 28.2% hypoxaemia⁺/pneumonia⁺, 22.2% hypoxaemia⁺/pneumonia^-, 14.5% hypoxaemia^-/pneumonia⁺ and 35.1% hypoxaemia^-/pneumonia^-. Mortality was 31.1% in the hypoxaemia⁺/pneumonia^- group and 26.3% in the hypoxaemia⁺/pneumonia⁺ group. Hypoxaemia with pneumonia and without pneumonia predicted higher probability of death. Hypoxaemia either <24 hours or ≥24 hours after hospitalisation predicted higher mortality and need for home oxygen compared with those without hypoxaemia. Patients with early hypoxaemia had higher probability of Intensive care unit (ICU) admission compared with those with late hypoxaemia.

Conclusion: Mortality in COVID-19 infection is predicted by hypoxaemia with or without pneumonia and was greatest in patients who initially presented with hypoxaemia. The emergence of hypoxaemia was predicted by radiographic pneumonia. Patients with early and emergent hypoxaemia had similar mortality but were less likely to be admitted to ICU. There may be delayed identification of hypoxaemia, which prevents timely escalation of care.

Keywords: COVID-19; adult intensive & critical care; adult thoracic medicine; public health; respiratory infections; thoracic medicine.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

COVID-19* / complications
Canada / epidemiology
Humans
Hypoxia / epidemiology
Hypoxia / etiology
Intensive Care Units
Pneumonia*
Retrospective Studies

Grants and funding

172754/CIHR/Canada