Received: 12 July 2020
Accepted: 21 December 2020
First Online: 12 February 2021
Conflict of interest
: The authors declare that they have no conflict of interest.
: This is an observational study. The Research Ethics Committee of the Medical Faculty of LMU Munich has confirmed that no ethical approval is required (17-829).
: Informed consent was obtained from all individual participants included in the study.