Editor note
It has been brought to our attention that this guidance (BMJ 2017;356:i6748 doi:10.1136/bmj.i6748) has now been updated by NICE. Please see the latest guidance at https://www.nice.org.uk/guidance/ng59

It has been brought to our attention that this guidance (BMJ 2017;356:i6748 doi:10.1136/bmj.i6748) has now been updated by NICE. Please see the latest guidance at https://www.nice.org.uk/guidance/ng59