Received: 7 November 2018
Accepted: 25 August 2019
First Online: 23 September 2019
Ethics approval and consent to participate
: The study has been performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and later amendments. This study was a retrospective analysis of administrative claims data and does not contain any human participants or animals. Thus, permission from a research ethics committee was not required and formal informed consent was not obtained.
: Not applicable.
: The authors declare that they have no competing interests.