Article History
Received: 28 July 2017
Accepted: 17 April 2018
First Online: 11 May 2018
Ethics approval and consent to participate
: The study is based on two anonymised retrospective datasets, no ethics approval was necessary.
: The authors SD, LA, VT declare that they have no competing interests, financial or non-financial. HP is an employee of the hospital UZLeuven which contributed data to both datasets.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.