Received: 6 November 2019
Accepted: 23 December 2019
First Online: 9 January 2020
Ethics approval and consent to participate
: This study was approved by the Medical Ethics Committees United (MEC-U), Nieuwegein, the Netherlands under number NL56169.101.15. The need for written informed consent was waived due to the retrospective design of the study.
: Not applicable
: The authors declare that they have no competing interests.