Factors associated with withholding of invasive mechanical ventilation in the early phase of the COVID-19 response and their ethical analyses

End-of-life decision making regarding invasive mechanical ventilation (IMV) for patients with severe coronavirus disease (COVID-19) is challenging. We aimed to explore the factors associated with the withholding of IMV in patients with COVID-19. This retrospective study included patients registered in a nationwide COVID-19 Registry Japan. We enrolled patients with COVID-19 admitted between January 1, 2020, and June 30, 2021, and died during hospitalization. The enrolled patients were divided into two groups: those who received IMV (IMV group) and those who did not (non-IMV group). To identify the factors associated with withholding of IMV among patients with COVID-19 who died during hospitalization, we conducted a multivariate logistic regression analysis. A total of 2,401 patients were enrolled. Of these, 588 (24.5%) were in the IMV group and 1813 (75.5%) in the non-IMV group. Withholding IMV was positively associated with older age (95% confidence interval [CI]: 0.82-0.88, <i>p</i> < 0.0001), dementia (95% CI: 0.81-0.91, <i>p</i> < 0.0001), chronic lung disease (95% CI: 0.88-1.00, <i>p</i> = 0.036), and malignancy (95% CI: 0.82-0.94, <i>p</i> < 0.0004) although inversely associated with male sex (95% CI: 1.04-1.15, <i>p</i> = 0.0008), body mass index (95% CI: 1.01-1.02, <i>p</i> < 0.0001), and National Early Warning Score (95% CI: 1.01-1.03, <i>p</i> < 0.0001). We subsequently analyzed these results to inform preparedness for future emerging infectious disease pandemics by retrospectively examining the decision-making processes during the COVID-19 crisis, with particular attention to the role of multidisciplinary collaboration. Based on this study, it will be essential in future pandemics to assess decisions concerning life-sustaining treatments, including IMV, from both scientific and ethical perspectives.