[Clinical characteristics and prognostic analysis of concurrent pneumonia in patients with idiopathic inflammatory myopathy].

To describe the clinical characteristics and to explore the prognostic factors of concurrent pneumonia (PJP) in patients with idiopathic inflammatory myopathy (IIM). We retrospectively enrolled consecutive IIM patients diagnosed with PJP at our center between January 2014 and December 2022. Fifty-eight IIM-PJP patients were enrolled in our study, with the age of 26-79 (56.3±12.1) years. There were 19 males (32.9%) and 39 females (67.1%). The participants were classified into survival group (21 patients) and non-survival group (37 patients) according to the clinical outcome. Cox regression models were used to analyze the prognostic factors. Compared with the survival group, there were more patients with anti- melanoma differentiation-associated gene (MDA5) positive, respiratory failure, hospital-acquired pneumonia, second-line PJP treatment, and caspofungin treatment in non-survival group (<0.05). Meanwhile, the time from onset of IIM, corticosteroid therapy, and immunosuppressant medication to diagnosis of PJP was significantly shorter in non-survival patients than survival patients (<0.05). Additionally, non-survival patients had higher neutrophil percentage and creatine kinase (<0.05), and lower lymphocyte count and percentage, platelets, minimal albumin, NK cell count, T cell count, and CD8T cell count (<0.05). Multivariate analysis showed that anti-MDA5 positive (=3.54, <0.05, 95%: 1.27-9.89), oral candidiasis infection (=2.62, <0.05, 95%: 1.07-6.43) and thrombocytopenia (=5.00, <0.01, 95% 1.88-13.32) were independent risk factors for IIM-PJP patients. Middle-aged females were the main IIM-PJP in our group, and the mortality rate was 63.8%. Anti-MDA5 antibody positive, oral candidiasis infection, and thrombocytopenia were independent survival risk factors for them.