Funding for this research was provided by:
Medical Research Council (G106/1177)
Article History
Received: 13 September 2017
Accepted: 16 January 2018
First Online: 25 January 2018
Ethics approval and consent to participate
: The study was approved by the Royal Free Hospital NHS Ethics Committee (06/Q0501/31). This included the procedure for verbal consent for the original data collection, which was allowed, at the time, because this was an observational study using measures routinely collected in clinical practice. Data was de-identified before we received it and used it for this analysis.
: Not applicable.
: The authors declare that they have no competing interests.
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