Thank you for this concise and helpful statement. Plainly, there will be much more to say on this question when the guidelines are eventually revised.

As you may be aware, guideline statements must be approved (in this case by the BTS Standards of Care Committee) and a further time period is then needed for preparation of a guideline supplement. The two studies to which you refer appeared only a month or two before the final publication of the guideline document and their exclusion from consideration was unavoidable. The BTS guideline group had concluded their deliberations very much earlier. Post hoc changes in guideline statements cannot be made by individuals at the proof reading stage.

However, this does highlight a problem with guideline statements: recommendations can be dated within a matter of months. Interstitial lung disease is currently changing rapidly as a speciality and, as the BTS guidelines may not be revised for a further 10 years, there is a strong case for brief updates every 2 years in which changes to the evidence base are summarised. This possibility will be explored.