Text and Data Mining valid from 2017-05-12
Received: 19 September 2016
Accepted: 28 April 2017
First Online: 12 May 2017
Compliance with ethical standards
: On behalf of all authors, the corresponding author states that there is no conflict of interest.
: Relevant ethical standards were considered in the conduct of this research, which was approved by the local NHS Trust Research and Development, who noted that further review was not required.
: Informed consent was not sought as this study considered collation of retrospective, routinely-collected data.
: This study received no external funding.