Characteristics of patients with connective tissue disease-associated interstitial lung diseases

Aim of the work: To characterize the clinical features and outcome in patients with connective tissue diseaseassociated interstitial lung disease (CTD-ILD). Patients and methods: The study included 74 adult patients with CTD-ILD following-up at the rheumatology and pulmonology outpatient clinics of two healthcare centers in Egypt between 2018 and 2023. Demographic, clinical, radiological and treatment data were collected. High-resolution computed tomography (HRCT), spirometer and 6-minute walk test (6MWT) were analyzed. Results: The patients mean age was 41.8 +/- 6.5 years, 89.2 % were females, systemic sclerosis (SSc) (44.6 %) and rheumatoid arthritis (RA) (33.8 %) were the most common diagnosed CTDs. 54.1 % of patients had nonspecific interstitial pneumonia (NSIP), and 33.8 % had usual interstitial pneumonia (UIP). 93.2 % showed abnormal spirometer. Established diagnosis of ILD was preceded and coincided with CTD diagnosis in 40.6 %. 35.1 % had lung affection >= 20 % which was significantly associated with RA (p = 0.001), onset of ILD before/with the diagnosis of CTD (p = 0.027), lower CTD duration (p = 0.01) and desaturation in 6MWT (p-0.006). Shorter CTD duration and 6MWT desaturation independently affected the extent of lung affection (p = 0.004 and p = 0.001 respectively). Conclusion: Both SSc and RA were the most frequent CTDs associated ILD. Spirometer, HRCT and 6MWT are valuable for early diagnosis. NSIP and UIP were the most frequent ILD patterns with variable outcomes. Severe lung affection was linked to RA, lower CTD duration, ILD onset before/with the CTD and desaturation in 6MWT. Shorter CTD duration and desaturation with 6MWT independently affected the percentage of lung affection.