Risk Factors Associated with Cardiac Involvement in Patients with Dermatomyositis/Polymyositis

Objective To identify risk factors associated with cardiac involvement (CI) in patients with dermatomyositis/polymyositis (DM/PM). Methods Medical records of 129 DM/PM patients were reviewed retrospectively. The risk factors associated with CI in those patients were screened through χ² tests or independent t tests before a multivariate logistic regression analysis was performed. ROC curves were constructed to determine diagnostic values of the identified risk factors. Results CI occurred in 59 (45.74%) of DM/PM patients, with 41 (69.49%) showing electrocardiographic (ECG) abnormality; 25 (42.37%) showing ultrasonic cardiogram (UCG) abnormality; 8 (13.56%) being diagnosed with heart failure, and 2 (3.39%) being diagnosed with myocardial infarction. Eight (13.56%) of the patients with CI died. CI was more likely to occur in patients with an older age, having interstitial lung disease, antinuclear antibody (ANA) positive, and anti-Jo-1 antibody positive (P<0.05). The logistic regression analysis revealed that interstitial lung disease (β=1.554), aspartic aminotransferase/creatine kinases (AST/CK) ratio (β=1.189), positive ANA (β=1.172) and age (β=0.042) were risk factors associated with CI (P<0.05). Notable areas under ROC curve (0.642) was found for AST/CK in determining CI in DM/PM patients (P<0.05), albeit with low accuracy. A cut-off of AST/CK ratio at 0.312 was identified as a reference point for determining CI in patients with DM/PM. Conclusion Cardiac involvement is the most common complication of DM/PM, although the majority are subclinical. ECG and UCG are common tools for diagnosing cardiac involvement. Interstitial lung disease, AST/CK ratio, positive ANA and age are predictors of CI in DM/PM patients.