Received: 22 July 2019
Accepted: 4 December 2019
First Online: 3 January 2020
Ethics approval and consent to participate
: This study received a positive ethics approval from the Ethics Committee of the Medical Faculty of the Heinrich Heine University Düsseldorf, Germany (Study-ID: 6021R; 25 July 2017). An amendment for the inclusion of a control group and confounding variables received a positive ethics approval on 20 February 2018. The data for the retrospective analysis were clinical routine data, which were anonymized at the point of data acquisition. The need for individual consent to participate was waived by the Ethics Committee. This study was obtained according to the Declaration of Helsinki on Ethical Principles for Medical Research Involving Human Subjects.
: Not applicable.
: The authors declare that they have no competing interests.