Received: 10 September 2020
Accepted: 11 December 2020
First Online: 23 December 2020
Ethics approval and consent to participate
: We obtained ethics approval from the SingHealth Centralised Institutional Review Board (2020/2760), Singapore, with waiver of documented informed consent. We obtained administrative permission to access the data used for our research.
: Not applicable.
: The authors declare that they have no competing interests.