Received: 24 July 2020
Accepted: 15 October 2020
First Online: 5 November 2020
Ethics approval and consent to participate
: The study was approved by the Institutional Review Board of Singapore (Reference Number: NHG DSRB 2014/00034). Waiver of informed consent was granted because our study used de-identified retrospective data and had minimal risk to the study participants.
: Not applicable.
: The authors declare that they have no competing interests.