High resolution computed tomography thorax findings in rheumatoid arthritis and its correlation with spirometry indices - a cross-sectional study.

Background: Rheumatoid arthritis (RA) is a chronic autoimmune disease primarily affecting joints but also leading to significant extra-articular manifestations. Pulmonary involvement in RA, especially interstitial lung disease (ILD), contributes substantially to morbidity and mortality. This study aims to evaluate the prevalence and pattern of lung involvement in RA patients and correlate these findings with spirometric indices.

Materials and methods: In this cross-sectional study, a total of 50 RA patients aged 18-55 years, diagnosed according to ACR-EULAR criteria, were enrolled. All participants underwent spirometry to measure FEV1, FVC, and FEV1/FVC ratios. Additionally, high-resolution computed tomography (HRCT) of the thorax was performed to identify patterns of lung involvement, including ground-glass opacity, honeycombing, interstitial thickening, and fibrosis. Statistical analyses were used to explore associations between disease duration, spirometric indices, and HRCT findings.

Results: Lung involvement was observed in 30 (60%) patients, with ground-glass opacities in 16 (32%) and interstitial thickening in 14 (28%) patients. ILD was detected in 13 (26%) patients, with usual interstitial pneumonia being the predominant pattern in 9 (69.2%) cases. A significant correlation was found between longer disease duration (>5 years) and the presence of abnormal spirometry findings (odds ratio [OR] = 16.0, 95% CI: 3.527-72.583, P = 0.000326; 63.2%, n = 12) as well as abnormal HRCT findings (OR = 6.476, 95% CI: 1.563-26.836, P = 0.01; 84.2%, n = 16). Patients with abnormal spirometry had significantly higher odds of showing abnormal HRCT findings (OR = 35.0, 95% CI: 7.629-160.719, P = 0.000084).

Conclusion: Abnormal HRCT findings and spirometry patterns correlate significantly with longer disease duration in RA. Early detection and management of pulmonary complications in RA may improve patient outcomes, particularly in those with long-standing disease. Furthermore, longitudinal studies are required to fully comprehend ILD progression in RA and its impact on patient prognosis.