Identifying predictors of systemic sclerosis-associated interstitial lung disease

Interstitial lung disease (ILD) is a major cause of morbidity and mortality in systemic sclerosis (SSc); yet, data from Middle Eastern populations remain limited. This study aimed to describe clinical characteristics, pulmonary involvement, and predictors of ILD in a Jordanian SSc cohort. A retrospective analysis was conducted on 129 adult patients with confirmed SSc based on the 2013 American College of Rheumatology/European Alliance of Associations for Rheumatology classification criteria or rheumatologist-confirmed diagnosis, all of whom had available high-resolution computed tomography (HRCT) scans. ILD was defined by fibrotic bands, ground-glass opacities, and honeycombing on HRCT, interpreted by an experienced radiologist. Patients were categorized into an old cohort (pre-2019, n = 71) and a new cohort (2019 or later, n = 58). Demographic, clinical, serologic, pulmonary function, and radiologic data were analyzed. Multivariable logistic regression was used to identify predictors of ILD. The cohort was predominantly female (90%) with a mean disease duration of 13.4 years. Mean age at symptom onset was 40.7 ± 13 years, with a diagnostic delay of 3.4 ± 5.1 years. ILD was present in 58.9% of patients and was more frequent in diffuse cutaneous SSc (dcSSc) compared with limited cutaneous SSc (77.2% vs 44.4%), with dcSSc associated with 2.82-fold higher odds of ILD (P < .001). HRCT was performed a mean of 6.9 years after diagnosis, indicating delayed ILD assessment. ILD prevalence was higher in the new cohort (69% vs 50.7%). Pulmonary arterial hypertension (PAH) occurred in 27.1% and was associated with ILD (P = .015). Patients with ILD had significantly lower diffusing capacity of the lung for carbon monoxide (DLCO), forced expiratory volume in 1 second, and forced vital capacity. Independent predictors of ILD included dcSSc, anti-Scl70 antibody positivity, PAH, and reduced DLCO. Treatment patterns differed between cohorts, with increased use of mycophenolate and nintedanib in the new cohort. Overall mortality was 11.6%, with ILD present in 80% of deaths. ILD is highly prevalent in Jordanian patients with SSc and is strongly associated with the diffuse disease subtype, anti-Scl70 positivity, PAH, and reduced DLCO. Delayed HRCT assessment may underestimate the true incidence. Early screening and adherence to international guidelines are essential to improve detection and outcomes.