Fig. 2

Correlation of polymorphonuclear (PMN) elastase levels with disease activity. Area under receiver operating characteristic (ROC) curve analysis was used to assess the ability of PMN elastase, creatine kinase (CK), and PMN elastase-to-neutrophil ratio (ENR) to distinguish between patients with active idiopathic inflammatory myopathies (IIMs), dermatomyositis (DM), and polymyositis (PM) and those in remission (a). The reference curve is also shown. The correlations between PMN elastase levels and myositis disease activity assessment (MYOACT) were assessed using Spearman’s rank correlation coefficients (b). Statistical significance is indicated by asterisks (*P < 0.5, ***P < 0.001)