Funding

Not applicable. The authors of this study received no financial support.

Conflicts of interest

David T.W. Lui, Tingting Wu, Ivan C.H. Au, Xiaodong Liu, Matrix M.H. Fung, Chi Ho Lee, Carol H.Y. Fong, Yu Cho Woo, Brian H.H. Lang, Kathryn C.B. Tan, and Carlos K.H. Wong have declared no conflicts of interest.

Ethics approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Ethics approval of this study was granted by the Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster (reference no. UW 21-320).

Consent to participate

Not applicable, as individuals were analysed anonymously and cannot be identified.

Consent to publication

Not applicable, as individuals were analysed anonymously and cannot be identified.

Availability of data and materials

The data that support the findings of this study are available from Hong Kong Hospital Authority but restrictions apply to the availability of these data, which were used under licence for the current study, and therefore are not publicly available. Data are however available from the authors upon reasonable request and with permission of Hong Kong Hospital Authority.

Code availability

Not available.

Author contributions

DTWL: Conceived the research idea, drafted the paper. TW: Conducted statistical analysis, drafted the paper. ICHA: Data management and reviewed the paper. XL: Data management and reviewed the paper. MMHF: Reviewed and validated the paper. CHL: Assisted data collection. YCW: Reviewed and validated the paper. BHHL: Reviewed and validated the paper. KCBT: Reviewed and validated the paper. CKHW: Conceived the research idea, data collection, supervised the project, and reviewed the paper. All authors read and approved the final version.