Stehle, P
Stoffel-Wagner, B
Kuhn, K S
Article History
Received: 21 July 2015
Revised: 3 February 2016
Accepted: 6 February 2016
First Online: 6 April 2016
Competing interests
: PS is consultant at Fresenius Kabi Deutschland, GmbH. The remaining authors declare no conflict of interest.