RA Independent ILD Risk — SCE Rheumatology MCQ

Correct answer: E — RA itself increases ILD risk; older age, male sex, smoking, seropositivity and active inflammation further increase risk.

RA-associated ILD is an extra-articular manifestation of RA and is not explained solely by antirheumatic drug exposure. Established clinical risk factors include older age, male sex, smoking, RF or anti-CCP positivity—particularly higher titres—and greater inflammatory disease activity. The MUC5B promoter variant is additionally associated with RA-ILD, especially the UIP pattern. Prevalence varies substantially with case ascertainment: contemporary analyses suggest approximately 10–13% in lower-bias or multimodally assessed populations, while systematic HRCT detects more subclinical disease. Methotrexate can cause a distinct, potentially acute hypersensitivity-type pneumonitis, but observational evidence does not show that it causes chronic fibrotic RA-ILD. Therefore B is incorrect; smoking increases but does not fully account for risk, excluding D. A and E incorrectly deny the persistent, independent association between RA and parenchymal ILD.

Reference: Antoniou KM et al. ERS/EULAR clinical practice guidelines for connective tissue disease-associated interstitial lung disease, RA screening algorithm, 2026. https://pubmed.ncbi.nlm.nih.gov/42078587/