Interstitial lung disease related to rheumatoid arthritis: evolution after treatment

To describe the evolution of lung function in a cohort of rheumatoid arthritis (RA) patients with interstitial lung disease (ILD) treated according to the medical judgment of attending physicians.

Retrospective cohort of RA patients with ILD, defined by a restrictive pattern in lung function tests and evidence of ILD in high resolution computed tomography (HRCT). Patients had an assessment of lung function including spirometry, diffusing capacity for carbon monoxide (DLCO), and HRCT. At a minimum of 4 months of follow up, a second assessment of lung function was done. All patients received a high dose of prednisone (1 mg/kg/day) scheme for 6 weeks with a reduction scheme ending with a dose of 10 mg/day of prednisone at about 6-8 months of follow up. Methotrexate was used in 18/40 (45%) patients and leflunomide or azathioprine or both were indicated in 22/40 (55%).

Forty patients were identified. An indeterminate pattern with diffuse ground glass and reticulation images (50%) was the most prevalent pattern on HRCT scans. At a minimum of 4 months of follow up, an improvement in basal FVC values was observed (median (IQR)) 1.47 Lts. (0.99-1.91) vs 1.66 Lts. (1.37-2.1)), P<0.004. Patients with lower Kazerooni scores for fibrosis (<0.47) had a better improvement in the FVC values.

Patients with RA and ILD may have an improvement in the FVC after a treatment with high doses of corticosteroids and disease modifying antirheumatic drugs (DMARDs).