Article History
Received: 6 March 2019
Accepted: 3 May 2019
First Online: 11 May 2019
Compliance with ethical standards
:
: None.
: According to Danish law, no ethical approval was necessary in this retrospective study.
: According to Danish law, it is illegal to contact patients to obtain informed consent in retrospective studies, but permission to conduct the study was given by the Danish Patient Safety Authority (# 3-3013-2825/1).