Letter to the Editor: Response to ‘Overlooked Shortcomings of Observational Studies of Interventions in Coronavirus Disease 2019: An Illustrated Review for the Clinician‘ by Tleyjeh et al

We commented on the publication by Tleyjeh et al regarding the overlooked shortcomings of observational studies of interventions in Coronavirus Disease 2019. Although we agree with Tleyjeh and colleagues on the issue of the competing risk bias in observational studies, the recommendations on the application of the Fine-Gray model provided by the authors are incomplete. The Fine-Gray approach may not be suitable in the presence of interval time-dependent covariates, that are often the case in the studies assessing therapeutic interventions for patients with Coronavirus Disease 2019.