Studio prospettico per la valutazione delle caratteristiche epidemiologiche e dei fattori associati all’interstiziopatia polmonare nei pazienti affetti da artrite reumatoide.

Background: Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is a clinically heterogeneous complication with substantial prognostic implications. This study investigated its frequency, clinical correlates, radiological phenotypes and longitudinal evolution. Methods: In this prospective observational study, 97 adults with rheumatoid arthritis were followed at the University Hospital of Sassari. Demographic, clinical, serological, laboratory and treatment variables were assessed at baseline and follow-up. High-resolution computed tomography was performed when clinically indicated. Associations with RA-ILD and usual (UIP) or nonspecific interstitial pneumonia (NSIP) patterns were explored, including logistic regression analyses. Results: At baseline, 14 patients (14.4%) had RA-ILD. Two new cases were identified during follow-up. Older age was the most consistent factor associated with RA-ILD, including in adjusted analyses at both time points. Higher quantitative anti-citrullinated protein antibody (ACPA) levels were associated with pulmonary involvement, particularly the UIP phenotype, whereas ACPA positivity alone showed no independent association. Dyspnea, fine inspiratory crackles and suggestive chest imaging were prominent clinical correlates. Joint disease activity and treatment exposure showed no stable associations. Phenotype-specific findings remained exploratory owing to small subgroup sizes. Conclusions: RA-ILD showed heterogeneous clinical and radiological features. Age and quantitative ACPA levels emerged as relevant clinical and serological correlates, highlighting the importance of integrated clinical and respiratory assessment for the early identification of pulmonary involvement. Further validation in larger prospective cohorts is warranted.