Funding for this research was provided by:
Deutsche Gesellschaft für Urologie (UhA1/FE-17)
Text and Data Mining valid from 2018-09-25
Received: 18 June 2018
Revised: 2 July 2018
Accepted: 12 July 2018
First Online: 25 September 2018
Compliance with ethical standards
: The scientific guarantor of this publication is Annemarie Uhlig.
: The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.
: Three of the authors have significant statistical expertise.
: Written informed consent was not required for this study because of the meta-analysis study design.
: Institutional Review Board approval was not required because of the meta-analysis study design.
: Study subjects or cohorts have been previously reported as detailed in the references.
: • observational