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Article History

Received: 16 July 2017

Accepted: 12 January 2018

First Online: 29 January 2018

Ethics approval and consent to participate

: Due to the study’s nature, which is a retrospective analysis of anonymised data without contact to patients, an ethic approval was not required according to German law. As the study only used routinely-collected, anonymized data, the issue of informed patients’ consent does not apply.

: Not applicable.

: The authors report no conflict of interest.

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