Received: 12 December 2017
Accepted: 8 October 2018
First Online: 5 December 2018
Ethics approval and consent to participate
: Routinely collected, retrospective, pseudonymised data were used for this analysis, with a data sharing agreement approved by Valentine Health data holders. Data were analysed as part of an audit and quality improvement initiative approved by the Valentine Health data holders. This study meets national guidelines set out by the Research Ethics Service for the National Health Service in England. No furthers ethics approval was required (ExternalRef removed).
: Not applicable.
: The authors declare that they have no competing interests.
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