Fig. 2.

Overview of included studies by disease group and study design*

*Totals were calculated based on the number of unique studies rather than articles. For IPF, two articles were based on the same trial (NCT00600028), counted as a single trial and two articles were derived from the same cohort/registry study (PROOF), counted as one observational study. Similarly, for CTD-ILD, three articles were based on the same trial, counted as a single trial (NCT00883129).

CTD-ILD, connective tissue disease-associated ILD; ILD, interstitial lung disease; IPF, idiopathic pulmonary fibrosis; PS, pulmonary sarcoidosis; RCT, randomised controlled trial