CRTAC1 and osteoarthritis: Determination of the reasons behind and significance of decreased CRTAC1 concentration in a subset of post‐COVID‐19 patients will require more detailed analysis of the roles of age, nature, and timing of the episode of COVID‐19, and conditions that drive plasma CRTAC1 concentration up, such as osteoarthritis (Styrkarsdottir et al., 2021, 2023; Szilagyi et al., 2023; Tardif et al., 2022), or down, such idiopathic pulmonary fibrosis (Mayr et al., 2021) or COPD (this study).