Received: 1 January 2020
Accepted: 30 January 2020
First Online: 12 February 2020
Compliance with ethical standards
: XinYan Yang, Lee Yuanming Alvin, Law Yan Mee, Sim Soon Phang Allen, Tay Kae Jack, Lau Kam On Weber, Ho Sun Sien Henry, Yuen Shyi Peng John, Kenneth Chen declare that they have no conflict of interest.
: All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2000.
: Informed consent was obtained from all patients for being included in the study.