Methotrexate (MTX) does not increase the risk for rheumatoid arthritis interstitial lung disease (RA-ILD) and may even reduce the risk, suggests new research published in BMJ Open.
The study used data from the early RA study (ERAS) and the early RA network (ERAN) to assess predictive factors for RA-ILD. ERAN included data from 23 secondary care centres in England, Wales and Ireland, while ERAS included nine centres.
The data show that, of 92 eligible ILD patients, 39 occurred in 1578 (2.5%) MTX exposed and 53 in 1114 (4.8%) non-MTX exposed patients.
The primary analysis of RA-ILD patients only developing after any conventional synthetic disease-modifying anti-rheumatic drug treatment (n=67) showed MTX exposure not to be associated with incident RA-ILD (OR, 0.85; 95% CI, 0.49-1.49; P=.578) and a non-significant trend for delayed ILD diagnosis (HR, 0.54; 95% CI, 0.28-1.06; P=.072).
In an extended analysis including RA-ILD patients present at RA diagnosis (n=92), MTX exposure was associated with a significantly reduced risk for incident RA-ILD (OR, 0.48; 95% CI, 0.30-0.79; P=.004) and longer time to ILD diagnosis (HR, 0.41; 95% CI, 0.23-0.75; P=.004).
Other independent baseline associations with incident RA-ILD were higher age of RA onset, ever smoking, male sex, rheumatoid nodules and longer time from first RA symptom to first outpatient visit.
“MTX treatment was not associated with an increased risk of RA-ILD diagnosis. On the contrary, evidence suggested that MTX may delay the onset of ILD,” the authors concluded.
