Fig. 3

Predictive model for the incidence of acute exacerbation of idiopathic interstitial pneumonia (AE-IIP). A decision tree for predicting AE incidence after the initial diagnosis of IIP was constructed by recursive partitioning (A). The partitioning process was completed when the study cohort was divided into four groups, namely low, moderate, high, and very high risk. PM/DM- and SSc-related antibodies included anti-ARS antibody, anti-Jo-1 antibody, anti-Scl70 antibody, anti-RNP antibody, anti-RNA polymerase III antibody, and anti-centromere antibody. Cumulative incidence of AE-IIP classified by the decision tree (B): blue line for low-risk group, green line for moderate-risk group, orange line for high-risk group, and red line for very high-risk group (p < 0.001). Kaplan-Meier curve of survival in each group by a predictive model for AE-IIP (C). FVC, forced vital capacity; AE, acute exacerbation; IIP, idiopathic interstitial pneumonia; ANA, antinuclear antibody; CCP, cyclic citrullinated peptide; ARS, aminoacyl tRNA synthetase; PM/DM, polymyositis/dermatomyositis; SSc, systemic sclerosis.