POS0588 USUAL INTERSTITIAL PNEUMONIA DURING RHEUMATOID ARTHRITIS: PREVALENCE AND ASSOCIATED FACTORS
Authors: C. Daldoul, N. El Amri, A. Guiga, S. Laataoui, K. Baccouche, H. Zegaloui, E. Bouajina
Journal: Annals of the Rheumatic Diseases (2021)

Background: Lung involvement is the second common extraarticular manifestation of rheumatoid arthritis (RA). Its prevalence varies widely according to the screening tool used and it could reach up to 80% of patients. This lung disease can affect all the lung compartments. However, interstitial lung disease during RA needs a particular attention due to the increased morbidity and usual interstitial pneumonia (UIP) pattern especially due to its higher rate of mortality. Objectives: To determine the frequency and associated factors of UIP among RA patients Methods: This was a retrospective study conducted at the Rheumatology department of Farhat Hached University Hospital from 2005 to 2020. We included all RA patients who had undergone high-resolution computed tomography (HRCT) scans of the lung. Demographic data, disease characteristics, pulmonary function tests (PFT) and drugs intake were collected at the time of the realization of the HRCT. UIP pattern and NON-UIP patterns were based on HRCT results. Khi-2 and T-student tests were used in the univariate analysis. Binary logistic regression was used in the multivariate analysis. Statistical significance level was set at 5%. Results: Fifty-nine patients with RA patients having HRCT of the lung were identified among them 27.1% (16) were male. The mean age of the patients was 60.27± 11.3 years; the mean disease duration was 7.16 ± 2.9 years and current or previous smoking habits were recorded in 18.8% (11) of our population with a median. Secondary Sjogren’s syndrome and cutaneous rheumatoid nodules were documented in 33.9% (20) and 10.17% (6) respectively. RA was erosive in 81.5% (48) of our population. The median tender joint count and the median swollen joint count were 10 and 4 respectively. The mean erythrocyte sedimentation rate (ESR) and the mean C-reactive protein (CRP) were 49±20.31 mm and 32±14.07 mg/dl respectively. The mean disease activity score (DAS 28 ESR) was 5.49±1.66. The median rheumatoid factor and Anti-CCP levels were 260UI/ml and 68 UI/ml respectively. Exertional dyspnea (stage 2 or higher) was present in 42.37% (25) and inspiratory crackles were found in 22.4% (13) of our patients. PFT revealed a restrictive ventilatory defect, an obstructive pattern and a mixed pattern were found in 20.3% (12), 13.6 (8) and 3.4% (2) respectively. The mean DLCO value was 70±24.6%. According to HRCT results, parenchymal involvement was found in 83.1% (49) of our patients and among them, we documented UIP pattern in 18 (36.73%), Non Specific Interstitial Pneumonia (NSIP) in 14.28% (7), unclassifiable fibrosis in 14.29 (7), organizing pneumonia in 2% (1) and isolated pulmonary nodules in 32.6% (16). Pleural effusion was found in 5.1% (3) and airways disease in 15.3% (9). Mediastinal lymphadenopathy was found in 15.25% (9). Abnormalities on HRCT lead to a change in treatment in 30.5% (18) of our patients. Compared to the group with a non-UIP pattern, male sex was significantly associated with UIP pattern on HRCT (47.4% vs. 17.5%, p=0.016). UIP pattern was significantly associated with smoking (37.5% vs. 9.4% p=0.022, Unadjusted OR=5.88, 95%IC=[1.217-27.634]), with cutaneous rheumatoid nodules (31.3% vs.3.4%, p=0.017, Unadjusted OR=12.72, 95IC=[1.331-121.658]) and with the presence of lymphadenopathy on HRCT (41.2% vs. 6.5%, p=0.004, Unadjusted OR=10.15, 95%IC=[1.803-57.140]). There was no significant difference between the two groups regarding age (p=0.454), disease duration (p=0.126), DAS28 (p=0.447), anti-CCP level (p=0.454). After multivariate analysis, male sex (Adjusted OR=11.58, 95%IC=[1.622-82.67] p=0.015), Presence of lymphadenopathy on HRCT (Adjusted OR=10.53, 95%IC=[1.146-96.87], p=0.037) and exertional dyspnea (Adjusted OR=6.43, 95%IC=[1.036-40.011], p=0.046) were independently associated with UIP pattern. Conclusion: UIP was present in 36.73% and it was the most prevalent pattern of lung involvement in RA. It was associated with male sex, mediastinal lymphadenopathy and exertional dyspnea. Disclosure of Interests: None declared