Cardiovascular risk and cardiac involvement in idiopathic inflammatory myopathies: insights from a cross-sectional Swedish single-centre study

OBJECTIVE: We aimed to investigate the cardiovascular profile, including risk factors and cardiovascular abnormalities, in patients with idiopathic inflammatory myopathies (IIMs). METHOD: In this cross-sectional study, 109 IIM patients and 20 age- and gender-matched healthy controls were enrolled and underwent electrocardiographic and transthoracic echocardiographic examinations. We analysed blood levels of cardiac troponin I (cTnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP), assessed IIM disease-specific features, and evaluated the medical history of cardiovascular risk factors. IIM patients were stratified into two groups: those with previous cardiac involvement and those without. RESULTS: IIM patients had a higher body mass index (BMI) and a greater prevalence of diabetes mellitus and dyslipidaemia than healthy controls (p = 0.023, p = 0.024, and p = 0.042, respectively). They also showed significantly higher rates of arrhythmia, cardiac axis deviation, negative T-waves, and suspected pulmonary hypertension, along with elevated NT-proBNP levels (p = 0.041, p = 0.004, p = 0.041, p = 0.012, and p = 0.034, respectively). A significantly higher proportion (p = 0.037) of immune-mediated necrotizing myopathy (IMNM) subtype (50%) was found among IIM with previous cardiac involvement compared to those without (20%). cTnI levels were significantly higher in IIM with cardiac involvement than in IIM without cardiac involvement (p = 0.009). CONCLUSIONS: Cardiovascular complications in patients with IIM may result from an increased prevalence of traditional cardiovascular risk factors, such as higher BMI, diabetes mellitus, and dyslipidaemia, and/or from direct cardiac involvement, such as previous myocarditis. Cardiac involvement in IIM is notably associated with the IMNM subtype.