PO:23:051 | Quantitative high-resolution computed tomography analysis in Sjögren’s disease-associated interstitial lung disease: CALIPER-derived imaging biomarkers for prognostic assessment

Gaetano La Rocca¹, Francesco Ferro¹, Vincenzo Uggenti², Beatrice Dei¹, Giovanni Fulvio¹, Michele Moretti¹, Chiara Romei², Marta Mosca¹, Chiara Baldini¹. | ¹University of Pisa, Rheumatology Unit, Clinical and Experimental Medicine Department, Pisa, Italy; ²Department of Diagnostic Imaging, Pisa University Hospital, Pisa, Italy.

Background. Interstitial Lung Disease (ILD) is a frequent manifestation of Sjögren’s Disease (SjD), associated with significant morbidity and mortality. However, data on the prevalence of progressive-ILD in SjD remain scarce, and biomarkers for predicting progression are lacking. Computer-Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER) is a validated CT-based software that quantifies ILD patterns such as ground-glass opacities, reticulation, honeycombing, and low attenuation areas. CALIPER-derived parameters correlate with pulmonary function tests (PFT) and outcomes in IPF and other autoimmune ILDs, but their role in SjD-ILD is unexplored. Our aim was to assess the prognostic value of CALIPER-derived parameters in SjD-ILD patients

Materials and Methods. SjD patients (2016 ACR/EULAR criteria) with HRCT-confirmed ILD followed from Jan-2018 to Sep-2023 were retrospectively included if >/=1 HRCT was suitable for CALIPER analysis. Clinical, laboratory and PFT data were collected at baseline and follow-up. Progressive-fibrosing ILD (PF-ILD) was defined (ATS criteria) by >/=2 of: worsening symptoms, FVC decline >/=5% or DLCO >/=10%, or radiological progression within 1 year. CALIPER-derived ILD% (sum of ground-glass, reticular, honeycombing) and VRS% (vascular-related structures) were calculated. Visual ILD extent (Warrick score) and pattern were assessed by a thoracic radiologist

Results. Twenty-three patients (F:M=18:5, mean age 66.2±9.5 yrs, mean follow-up 6.1±5 yrs) were enrolled. ILD patterns included NSIP (n=14), UIP (n=6), and NSIP+OP (n=3). Dyspnea and cough occurred in 21 and 19 patients respectively. Median baseline FVC and DLCO were 83% and 64%. Seventeen patients received immunosuppressants; none received antifibrotics. Seven required long-term oxygen (LTO2) and 7 developed PF-ILD. Baseline ILD% and VRS% demonstrated a moderate-strong correlation with FCV% and DLCO%, visual ILD quantification (Warrick score) and between them (table 1). VRS%, Reticulation%, and Honeycombing% were significantly higher in UIP (p=.021, .038, .047 respectively). On univariate regression analysis, VRS% (OR 3.2, 95%CI 1.1-9.1, p=.03) and ILD% (OR 1.13, 95%CI 1.01-1.3, p=.05) were associated with LTO2. According to ROC analysis, VRS% had an AUC of 0.813 (p=.019) with an optimal cut-off of 3.8% yielding a sensitivity of 71.4% and a specificity of 87.5% in predicting LTO2. ILD% had an AUC of 0.777 (p=.038) with a cut-off of 11.6% resulting in a 71.4% sensitivity and a 75% specificity in predicting LTO2. On univariate analysis VRS% (OR 2.8, 95%CI 1-8, p=.05) was associated with a PF-ILD behavior in the next year, with an AUC of 0.85 (p=.023) and an optimal cut-off of 3.8% resulting in a 83.3% sensitivity and 80% specificity.

Conclusions. CALIPER-derived parameters correlate strongly with lung function and predict adverse outcomes in SjD-ILD. Automated HRCT analysis offers promising digital biomarkers for ILD assessment and risk stratification. Integrating these metrics with clinical and functional data could support early identification of progressive-ILD and guide therapy. Further validation in larger cohorts is warranted.