Funding for this research was provided by:
Chief Scientist Office (CZH/4/41118)
Received: 31 July 2018
Accepted: 10 December 2018
First Online: 11 January 2019
: Letters of comfort were issued by the West of Scotland NHS Ethics Committee and the University of Glasgow College of Medical, Veterinary & Life Sciences Ethics Committee confirming that the full study did not need NHS ethics permission. Public Benefit and Privacy Panel approval was granted by NHS Information Services Scotland in December 2016. Data were aggregated where necessary to ensure individual patient privacy.
: No personal information was given so consent to publish was not applicable.
: The authors declare that they have no competing interests.
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