Semiquantitative HRCT scoring: a reliable predictor of rapidly progressive interstitial lung disease in patients with anti-MDA5 positive dermatomyositis.

Background: Anti-melanoma differentiation-associated gene 5 positive dermatomyositis (anti-MDA5 DM) is strongly linked to rapidly progressive interstitial lung disease (RP-ILD), which is associated with high early mortality. This study aimed to explore the feasibility of using semiquantitative visual scoring methods on high-resolution computed tomography (HRCT) to assess RP-ILD in anti-MDA5 DM patients, and to develop a risk prediction model for RP-ILD, given the poor prognosis of RP-ILD in anti-MDA5 DM. Methods: The data of patients with anti-MDA5 DM were retrospectively analyzed. Seven HRCT-based semiquantitative scoring methods were used to assess the extent of interstitial lung disease (ILD), and the correlation of each method with the pulmonary function tests (PFTs) was analyzed. The diagnostic performance of each method for RP-ILD was also evaluated. A nomogram model was developed to predict RP-ILD risk. Results: In total, 67 patients with anti-MDA5 DM were included in the study. Methods 1, 2, 4, 5, and 6 significantly distinguished RP-ILD from non-RP-ILD (P<0.05). Method 1 showed the highest correlation with the PFTs and the best diagnostic performance for RP-ILD [area under the curve (AUC) =0.766, P<0.001]. The least absolute shrinkage and selection operator logistic regression analysis identified male sex, an advanced age at onset, fever, a decreased normal extent in the left lower lung zone, an increased consolidation extent in the left middle lung zone, and elevated C-reactive protein as predictors of RP-ILD. These six predictors were used to construct a prediction model, which had an AUC of 0.842 based on internal validation, and showed good predictive ability and clinical applicability after the calibration and clinical decision curve analyses. Conclusions: Semiquantitative visual scoring based on HRCT can effectively assess the severity of ILD in anti-MDA5 DM patients. A predictive model for RP-ILD that incorporates imaging and clinical information has potential for clinical application.