PO:08:116 | Rheumatoid nodulosis: incidence, clinical/instrumental description, and phenotypic correlations in patients with rheumatoid arthritis treated with b-DMARDs. A real-life analysis from a monocentric cohort

Stefano Ruggiero¹, Elisa Montebelli³, Simone Bernardi², Marcello Natali⁴, Francesca Martelli¹, Alessandra Caula¹, Federica Landolfini¹, Gabriella Cucinotta¹, Sofia Giulianelli¹, Francesco Girelli² | ¹UOC Medicina Interna, Ospedale Morgagni-Pierantoni; Dipartimento di scienze Mediche e Chirurgiche Università di Bologna; ²UOS Reumatologia, Ospedale Morgagni-Pierantoni, Forlì; ³Università degli Studi di Bologna; ⁴UOC Radiologia, Ospedale Morgagni-Pierantoni, Forlì, Italy

Background. Rheumatoid nodulosis is the most common cutaneous manifestation of rheumatoid arthritis (RA), with an estimated prevalence of 20–30%. Less frequently, it involves the lungs (<1%), presenting as rheumatoid pulmonary nodulosis. This preliminary study describes a group of RA patients treated with b-DMARDs, analyzing the prevalence of pulmonary and extrapulmonary nodules and potential clinical associations.

Materials and Methods. A retrospective, monocentric, observational study was conducted on 82 RA patients treated with b-DMARDs for at least 12 months. One patient was excluded due to insufficient data. Demographic and clinical features, presence and type of nodules (radiological/histological), and variations in DAS28 at baseline and after 12 months of b-DMARD therapy were analyzed.

Results. Of the 82 patients, 65 were women (79.3%), with a median age of 62.5 years and a median disease duration of 11.8 years. Active smoking was reported in 18.3% and previous smoking in 29.3% of cases. RF and CCP tests were negative in about 23% of patients. At diagnosis, 2 patients were untreated; 24 were on monotherapy (predominantly methotrexate), and 56 on combination therapy. The median time between diagnosis and initiation of biologic therapy was 6.14 years (mean 10.33; skewness 1.13). At baseline, DAS28-4v indicated high disease activity in 30.5% of patients, moderate activity in 41.5%, and remission in 13.4%. After 12 months, 50% achieved remission, 62.2% showed clinical improvement, 20.7% remained stable, and 6.1% worsened. The mean DAS28 reduction was similar across different b-DMARD classes, consistent with literature data. Pulmonary nodules were detected in 23 patients, extrapulmonary in 12, and multiple-site nodules in 5. Among patients with pulmonary nodules, 6 had overlap syndromes (Sjögren’s, systemic sclerosis, or mixed connective tissue disease), and 65.2% were current or former smokers. Nodules were bilateral in 15 cases, cavitated in 3, and located randomly, in the pleural mantle, or parenchyma. In 12 cases, the pulmonary background was altered (ILD or emphysema). Histological data were available in only 4 cases, with one showing findings consistent with RA. The estimated prevalence of rheumatoid pulmonary nodulosis was 1.21%. The mean DAS28 reduction was comparable among anti-TNFα, anti-IL6, and anti-CD20 agents, with moderate variability, in line with published studies. Overall efficacy was good, although the limited sample size reduced comparative power.

Conclusions. Preliminary results show a prevalence of rheumatoid pulmonary nodulosis consistent with existing literature and confirm the overall efficacy of b-DMARDs in reducing DAS28. Study limitations include lack of a control group, small sample size, and limited histological data. Further studies are needed to better clarify potential correlations between biologic therapy and nodulosis development.