Methotrexate may delay onset of interstitial lung disease in RA
Treatment with methotrexate (MTX) does not contribute to an increased risk of interstitial lung disease (ILD) in patients with rheumatoid arthritis (RA) and rather delays ILD onset, according to a study.
Researchers drew data from two early RA inception cohort studies, the early RA study (ERAS) and the early RA network (ERAN), and identified 2,701 RA patients. They collected data including demographics, drug therapies and clinical outcomes such as the presence of RA-ILD at baseline, within 3–6 months, at 12 months and annually thereafter.
There were 92 RA-ILD cases, which was recorded in 39 of 1,578 (2.5 percent) patients who were exposed to MTX and in 53 of 1,114 (4.8 percent) patients who were not exposed.
Analysis of the primary outcome of the relationship of MTX use with RA-ILD diagnosis was restricted to cases where ILD was only diagnosed after exposure to any conventional synthetic disease-modifying antirheumatic drug (csDMARD; n=67), excluding 25 cases with ILD recorded at baseline.
Results revealed no association between MTX and incident RA-ILD (odds ratio [OR], 0.85, 95 percent CI, 0.49–1.49; p=0.578) and a nonsignificant trend for delayed ILD diagnosis (OR, 0.54, 0.28–1.06; p=0.072).
In an extended analysis including all RA-ILD cases (n=92), MTX use significantly cut the risk of incident RA-ILD (OR, 0.48, 0.3–0.79; p=0.004) and prolonged time to ILD diagnosis (OR, 0.41, 0.23–0.75; p=0.004).
Factors independently associated with incident RA-ILD were higher age at RA onset, ever smoking, male sex, rheumatoid nodules and longer time from first RA symptom to first outpatient visit.
In light of the findings, researchers emphasized that the association of MTX and hypersensitivity pneumonitis with the onset of RA-ILD should not be confused.
Supposing lung function at baseline is adequate to withstand an episode of hypersensitivity pneumonitis, there are no other respiratory contraindications to the use of MTX, which is a very effective anchor of csDMARD in RA, they added.