Prognostic factors for interstitial lung disease progression in rheumatoid arthritis: May methotrexate protect against progression?

Objective: Lung computed tomography (CT) is a valid method for the detection and assessment of the progression of interstitial lung disease (ILD) in rheumatoid arthritis (RA) patients. The objective of this study is to conduct a comparative analysis of the characteristics of individuals with RA-ILD, with and without radiographic progression, determined using lung CT scans.

Method: In this retrospective observational study, three radiologists re-evaluated CT scans of RA-ILD patients who had at least one follow-up CT. The lungs were divided into upper, middle, and lower zones, with equal slices. Progression was defined as the involvement of more zones in the vertical extent by the same elementary findings or the emergence of more severe findings in the same zones compared to the previous examination. Logistic regression analysis was used to assess the possible factors identified in univariate analysis.

Results: This study included 104 patients with 215 lung CT scans for analysis. Radiographic progression was seen in 43 patients (41.3%). Male sex, findings compatible with ILD on the last X-ray, age at diagnosis of ILD > 50 years, and presence of ground-glass opacity on CT were more common in the group with progression. In multivariate analysis (adjusted for ILD disease duration), findings consistent with ILD on chest X-ray and male sex were independent risk factors for progression, while taking methotrexate (ever) was an independent protective factor for progression.

Conclusion: Our findings indicate a negative association between methotrexate use and ILD progression. These results should be confirmed in further studies.