What is the Link between Lung Involvement and Anti-CCP Antibodies in Rheumatoid Arthritis: A Cross-sectional Study

Background: In Rheumatoid Arthritis (RA), pulmonary involvement is one of the most frequent extra-articular manifestations. Several studies have demonstrated an association between RA-related lung disease and the positivity of anti-cyclic citrullinated peptide (anti-CCP) antibodies. Objective: Our aim is to describe the frequency of pulmonary involvement in the RA population and investigate the association between anti-CCP antibodies and diverse lung compartment involvement in RA patients. Methods: An observational retrospective cross-sectional study was conducted, during which data were collected from the medical records of the patients with RA who had been tested for anti-CCP antibodies and had thoracic high resolution computerized tomography (HRCT) evaluation from January 2011 to March 2022. The univariate and multivariate analyses using logistic regression models was performed to calculate odds ratios (ORs) with 95% CIs. Results: A total of 390 patients with RA were included, the mean age of patients was 58.99 ± 12.44 years, with a predominance of females (85.9%). Two hundred and fifty-two (64.6%) patients were positive for anti-CCP antibodies. The frequency of RA-related lung diseases was 14.4% (n=56). The different manifestations observed in the thoracic HRCT included Nodules (67.9%), Interstitial lung disease (ILD) (28.6%), bronchiectasis (25%), fibrosis (21.4%), obliterative bronchiolitis (7.1%), and pleuritis (1.8%). In univariate and multivariate analysis, pulmonary involvement was associated with positive anti-CCP antibodies with an odds ratio (OR) of 5.25 (95% CI: 2.17-12.70, p < 0.0001). Conclusion: The study demonstrated a positive association between anti-CCP antibodies and pulmonary involvement in RA and highlighted the importance of tight monitoring in RA patients with positive anti-CCP for pulmonary complications.