Received: 13 August 2017
Accepted: 18 June 2018
First Online: 22 June 2018
Ethics approval and consent to participate
: This study was approved by Chang Gung Medical Foundation Institutional Review Board, and access to the National Health Insurance Research Database (NHIRD) was permitted by the National Health Research Institutes in Taiwan. Since the identification numbers of all subjects in the NHIRD were encrypted to protect the privacy of the individuals, the informed consents were waived. All the lack of consent forms is in accordance with Chapter II, “Information Collection, Processing and Use by a Government Agency”, of the Personal Information Protection Act of Taiwan.
: Not applicable
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.