Funding for this research was provided by:
Ministry of Science and Technology, Taiwan (MOST 101-2314-B-010-038-MY3, MOST 102-2314-B-010-034-MY3)
Received: 22 April 2018
Accepted: 2 August 2019
First Online: 19 August 2019
Ethics approval and consent to participate
: This study has been approved by a research ethics committee of Institutional Review Board of National Yang-Ming University. Both databases (NHIRD and LHID) are only open to academic personnel in Taiwan for research purposes. Both databases are regulated and managed by the Ministry of Health and Welfare. We submitted an official application for the databases to the National Health Research Institute according to the regulations of the Ministry of Health and Welfare, and we received the administrative permission to access and use the datasets for research purposes.
: Not applicable.
: Nicole Huang is a member of the editorial board of this journal---BMC Health Service Research. Besides, the authors declare that they have no other competing interests.