Table 2:

Selected studies investigating RA-ILD or pulmonary abnormalities in early-RA (within 1–2 years of articular RA diagnosis).

Study	Country	Study Period	Population	n	Methods of detection of ILD or other pulmonary abnormalities	Findings
Reynisdottir, et al.[11]	Sweden	n/a	New RA diagnosis, no treatment	105	HRCT	63% of ACPA-positive with pulmonary abnormalities
Doyle, et al.[31]	USA	n/a	New RA diagnosis, no treatment	18	ABG, CXR, spirometry, plethysmography, eucapneic hyperventilation	53% with at least 1 abnormality
Gabbay, et al.[30]	Australia	n/a	RA <2 years duration	36	CXR, HRCT, BAL, PFTs, nuclear scan	Clinical RA-ILD in 14% Subclinical RA-ILD in 44%
Habib, et al.[32]	Saudi Arabia	2007–2009	RA <2 years duration	40	HRCT, PFTs	Clinical RA-ILD in 10% Subclinical RA-ILD in 35%
Dong, et al.[34]	USA	2011–2013	RA <1 year duration	18	HRCT, PFTs	39% with abnormalities
Mori, et al.[33]	Japan	2003–2007	RA <1 year duration	65	HRCT, PFTs	13.8% with classic ILD pattern

ABG = arterial blood gas; BAL = bronchoalveolar lavage; CXR = chest radiograph; ILD = interstitial lung disease; HRCT = high resolution computed tomography; n/a = not available; PFTs = pulmonary function tests; RA = rheumatoid arthritis.