This study evaluated the neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) as indicators for diagnosing rheumatoid arthritis (RA) complicated by interstitial lung disease (RA-ILD).

The study included 163 newly diagnosed RA patients, divided into RA (122) and RA-ILD (41) groups. During a 2-year follow-up, ILD developed in 10 RA patients, and 17 RA-ILD patients required ILD treatment.

NLR and PLR were higher in the RA-ILD group (p < 0.05). Optimal diagnostic thresholds were 3.15 for NLR and 152.62 for PLR, with AUCs of 0.615 and 0.61, respectively. Sensitivity was 72% for NLR and 62% for PLR, with specificities of 54% and 64%. NLR and PLR increased with ILD, while lung function measures decreased (p < 0.05). After treatment, NLR and PLR decreased, and lung function improved (p < 0.05). Both ratios correlated negatively with lung function measures pre- and post-treatment (p < 0.05).

Elevated NLR and PLR suggest RA complicated by ILD and can serve as treatment effect indicators for RA-ILD.