Interstitial lung disease with and without pulmonary symptoms at the onset of inflammatory rheumatic disease - similarities and differences

Objective: Interstitial lung disease (ILD) is a common and serious organ manifestation in patients with inflammatory rheumatic disease (IRD), but it is uncertain whether there is a difference in ILD between symptomatic and asymptomatic patients. Therefore, we conducted a study to evaluate differences in the extent of ILD based on radiological findings between symptomatic/asymptomatic patients, using an artificial intelligence (AI)-based quantification of pulmonary high-resolution computed tomography (AIpqHRCT). Methods: Within the study, 67 cross-sectional HRCT datasets and clinical data (including pulmonary function test) of consecutively patients with both, initial diagnosis of IRD and ILD (all without immunosuppressive therapy), were analysed using AIqpHRCT. Results: 25.4% of the patients with ILD at initial diagnosis of IRD had no pulmonary symptoms. The pulmonary function test (PFT) revealed the following mean values (%predicted) in the symptomatic and asymptomatic group, respectively: Forced vital capacity (FVC) 69.4 ± 17.4% versus 86.1 ± 15.8% (p = 0.001), and diffusing capacity of the lung for carbon monoxide (DLCO) 49.7 ± 17.9% versus 60.0 ± 15.8% (p = 0.043). AIqpHRCT data showed a significant higher amount of high attenuated volume (HAV) (14.8 ± 11.0% versus 8.9 ± 3.9%; p = 0.021) and reticulations (5.4 ± 8.7% versus 1.4 ± 1.5%; p = 0.035) in symptomatic patients. Conclusion: A quarter of patients with ILD at the time of initial IRD diagnosis had no pulmonary symptoms, showing DLCO were reduced in both groups. Also, AIqpHRCT clinically relevant ILD in asymptomatic patients. These results emphasize a routine ILD screening should also be carried out in asymptomatic IRD patients, as ILD is associated with increased mortality.