Factors associated with pulmonary function decline in patients with rheumatoid arthritis-associated interstitial lung...

Antifibrotic drugs have recently been recommended for patients with interstitial lung disease with progressive pulmonary function decline. However, the clinical characteristics of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) with progressive pulmonary function decline, including the relationship with RA disease activity, are unclear.

This retrospective study included patients diagnosed with RA-ILD at our hospital from 2011 to 2019 for whom data on pulmonary function tests (PFTs) and chest high-resolution computed tomography (HRCT) were available. Factors associated with a percent forced vital capacity (%FVC) absolute decline were determined using multivariate regression analysis, and a scoring system based on the results of the multivariate logistic regression analysis was developed to identify patients with progressive RA-ILD with an absolute decline in %FVC of ≥5 %.

A total of 92 patients were enrolled, and the multivariate regression analysis showed that older-age (β, -0.27; 95 % confidence interval [CI], -0.49 to -0.05), worse Disease Activity Score 28-erythrocyte sedimentation rate (DAS28-ESR) (β, -1.52; 95 % CI, -2.61 to -0.42), and HRCT modified-fibrosis score (FS) increase (β, -0.39; 95 % CI, -0.53 to -0.25) were negatively correlated with %FVC absolute change. The new scoring system to identify the progressive-RA-ILD patients based on five factors (advanced-age, male, increasing modified-FS, increasing ground-glass opacities, and worsening DAS28-ESR) showed an area under the curve of 0.830 (95 % CI, 0.731-0.929).

The scoring system combining five factors may be useful in estimating progressive-RA-ILD patients without conducting PFTs and help clinicians reconsider appropriate treatments with antifibrotic drugs and/or immunosuppressive therapies to control RA disease activity and suppress progressive pulmonary function decline.