Text and Data Mining valid from 2019-08-01
Received: 5 January 2019
Accepted: 25 June 2019
First Online: 1 August 2019
Ethics approval and consent to participate
: This multicenter retrospective cohort study was performed after having obtained approval from each hospital’s institutional review board (Delegate: Toho University Ohashi Medical Center, approval no. 15–46).
: Not applicable.
: The authors declare that they have no competing interests.