Clinical characteristics and factors associated with dysphagia in idiopathic inflammatory myopathy: A cross-sectional observational study

OBJECTIVE: To investigate the clinical and laboratory characteristics of idiopathic inflammatory myopathy (IIM) patients with dysphagia and determine associated factors. METHODS: We conducted an observational study of 96 patients with IIM in the Department of Rheumatology and Immunology at Ma'anshan People's Hospital from September 2019 to June 2024, whose swallowing function was assessed and recorded. Clinical and laboratory characteristics were compared between patients with and without dysphagia in this cross-sectional study. Logistic regression analysis was used to identify factors associated with dysphagia in patients with IIM. RESULTS: Among the 96 patients with IIM, 20 (21%) experienced dysphagia. The incidence was 2 of 9 patients (22%) with polymyositis, 12 of 54 patients (22%) with dermatomyositis, 2 of 27 patients (7%) with antisynthetase syndrome, and 4 of 6 patients (67%) with immune-mediated necrotizing myopathy (IMNM), with significant differences (P=0.015). Patients with dysphagia exhibited significantly higher levels of creatine kinase-MB isoenzyme (CK-MB), lactate dehydrogenase, serum ferritin, rates of concomitant tumor, and positivity for autoantibodies directed against transcription intermediary factor 1-γ (anti-TIF1γ) and against the signal recognition particle (anti-SRP) than those without (all P<0.05). Logistic regression analysis indicated that anti-SRP antibodies, anti-TIF1γ antibodies, concomitant tumor, and elevated CK-MB levels were independent risk factors for the development of dysphagia in patients with IIM. Receiver operator characteristic curve (ROC) analysis demonstrated that the areas under the curve (AUC) for anti-TIF1γ antibody, concomitant tumor, and CK-MB levels alone in predicting dysphagia in IIM patients were 0.699, 0.759, and 0.656, respectively. The combined predictive model yielded an area under the curve (AUC) of 0.914. CONCLUSION: Dysphagia is not rare in patients with IIM. It is important to be vigilant for the occurrence of dysphagia in IIM patients positive for anti-SRP antibodies, anti-TIFγ antibodies, concomitant tumors, and elevated CK-MB levels. Anti-TIF1γ antibodies, concomitant tumors, and elevated CK-MB levels may have potential value in identifying IIM patients at higher risk of dysphagia.