To the Editor:
The interesting manuscript by du Bois et al. [1] states in the discussion section that “only two previous studies have demonstrated an independent association between 6MWD and the risk of mortality in patients with IPF”, quoting the studies of Caminati et al. [2] and of Lederer et al. [3].
It should be noted that in 2012 the European Respiratory Journal published a study demonstrating the significant and independent association between 6-min walk …