ACPA is a main risk factor for CT-proven pulmonary nodule progression in patients with rheumatoid arthritis.

Objectives: To determine the features of rheumatoid pulmonary nodules and the factors associated with nodule progression in patients with rheumatoid arthritis.

Methods: Between January 2010 and September 2018, RA patients with at least one chest computed tomography (CT) were included. Two experienced radiologists examined chest CTs. Nodules with changing dimensions on follow-up or at least two nodules with different sizes or cavitary nodules were considered rheumatoid pulmonary nodules. To identify follow-up changes in the nodules, progression was defined as the appearance of any new nodules or increase in the size of the nodules, regression was no new nodules and no increase in the size of any nodules and decrease in the size of at least one nodule, and stability was no appearance of new nodules and no change in the size of nodules and no disappearance of the nodule. We compared the demographics, comorbidities, RA-specific treatments, and nodule characteristics according to seropositivity. Factors that may be associated with RPN progression were studied.

Results: A total of 204 (136 (66.7%) female) patients were included in the study. The median disease duration at baseline CT was 7.29 years (0.05-57.5). Pulmonary nodules were detected in the first CT of 21 (10.2%) patients before RA diagnosis, with a median time of 10.38 (0.46-254) months. The median number of nodules and median diameter of the dominant nodule were higher, and cavitation was more prevalent in seropositive patients. ACPA positivity was independently associated with progression (OR 3.69 (1.33-12.4), p = 0.03). Cs-DMARDs and b/ts-DMARDs, especially anti-TNF agents, did not affect nodule progression.

Conclusion: Rheumatoid pulmonary nodules may precede RA, and seropositivity, especially ACPA, is an important independent risk factor for RPN occurrence and progression. Key Points • Rheumatoid pulmonary nodules were mainly located peripherally, in the right lobe, and had a high cavitation rate. • ACPA positivity was found as a main effective factor in RPN progression. • Cs/b-DMARD treatments were not associated with RPN progression.