Clinical features and a Nomogram for predicting clinical response in juvenile dermatomyositis associated interstitial lung disease.

Abstract

Juvenile dermatomyositis (JDM) is a rare autoimmune disease and accompany by interstitial lung disease (ILD), a major cause of morbidity and mortality. However, data on clinical features and prognosis of JDM-ILD in Chinese pediatric populations remain limited. The aim is to characterize the clinical features, treatment options and prognosis of JDM-ILD in Chinese pediatric patients, and to develop a nomogram for predicting clinical response. We retrospectively enrolled 244 JDM-ILD patients from Beijing Children's Hospital (May 2015-January 2026). Demographic, clinical, laboratory, treatment, and prognostic data were collected. Clinical response was assessed through a combination of PRINTO-defined clinical inactive disease (CID) , respiratory symptoms and HRCT. Independent prognostic factors were identified using Cox regression analysis and incorporated into a nomogram. Model performance was assessed using C-index, calibration curves and decision curve analysis (DCA). Among 244 patients (55.7% female, median onset age 5.7 years), anti-MDA5 (32.0%) and anti-NXP2 (13.9%) were the most prevalent autoantibodies. At last follow-up visit, 202 patients (82.8%) achieved CID, with CID rates increasing progressively over time. A total of three patients who tested positive for anti-MDA5 antibody died of RP-ILD (median survival 2.7 months). Multivariable Cox regression identified combination therapy with JAK inhibitors (HR 2.09, 95%CI 1.25-3.50) or IL-6 inhibitors (HR 1.83, 95%CI 1.07-3.12) and Gottron's sign (HR 1.80, 95%CI 1.10-2.96) as favorable factors for CID, while high-risk status (HR 0.23, 95%CI 0.10-0.57), higher DAS skin score (HR 0.71, 95%CI 0.48-1.00), and higher neutrophil-to-lymphocyte ratio (NLR) (HR 0.84, 95%CI 0.72-0.97) predicted lower probability of CID. The nomogram showed predictive performance in both training cohort (AUC: 0.67, 0.77, and 0.78 at 1, 3, and 5 years) and testing cohort (AUC: 0.60, 0.78 and 0.77 at 1, 3, and 5 years). This nomogram for predicting clinical response in Chinese pediatric JDM-ILD patients integrates clinical features and treatment variables to enable individualized risk stratification. Combination therapy with JAK or IL-6 inhibitors demonstrates promising efficacy and may improve outcomes.