Individualised Trajectories of Patients with COVID-19 Refute Population Mortality Data

Abstract

Background: COVID-19 syndrome is a world-wide pandemic with multiple international publications demonstrating mortality for those admitted to intensive care to be between 46 – 88%. The experience at Chelsea & Westminster’s hospital has been dramatically different from those reported with a mortality of 24·4%. We sought to analyse this difference retrospectively in a case-cohort study. Methods: Whole case of 16 non-survivors with 15 closely matched survivors (age and APACHE-II) were analysed and compared to UK national published data. Patients trajectories were aligned according to the lowest PaO2/FiO2 ratio. Lymphocyte count, ferritin and organ support data were also aligned to PaO2/FiO2 ratio to demonstrate trends in patient trajectories. Findings: Following alignment, patient trajectories were in opposition to aggregated population data suggesting Simpson’s paradox is present in COVID-19 mortality data; a form of confounding. Population based data suggests that patients’s respiratory function declines till death but following alignment, it is shown that respiratory function and lymphocytes recover prior to death. Importance: Data from this study suggests that the day 10 – 15 nadir in respiratory function will improve. Consideration of withdrawal of care should be based on individual cases as aggregated data is misleading and late recovery may occur. Funding Statement: None applicable. Declaration of Interests: None declared by all authors. Ethics Approval Statement: The study was approved by the Chelsea and Westminster NHS Foundation Trust clinical governance team. As the report involves routinely collected non-identifiable clinical audit data, no ethical approval was required under the UK policy framework for health and social care.