Received: 4 May 2021
Accepted: 29 September 2021
First Online: 11 October 2021
: This was a retrospective cohort study conducted at the Singapore General Hospital. This study was approved by the Institutional Review Board prior to its initiation (SingHealth Centralized Institutional Review Board (CIRB) 2014/651/D). The informed consent of the participants was not required for this study because it was a retrospective cohort study. Written informed consent was waived by the SingHealth CIRB because our study did not involve the privacy or treatment of patients. The study protocol was performed in accordance with the relevant guidelines.
: Not applicable.
: The authors declare that they have no competing interests.