Relevance of serum cardiac biomarkers in patients with dermatomyositis/polymyositis

Abstract

Patients with inflammatory myopathies (IM) with cardiac involvement have worse prognosis. Therefore, early identification cardiac involvement would be critical for clinical practice. In this study, we will evaluate high-sensitivity Troponin I (hs-cTnI) serum levels in patients with IM. Aims: The aim of our study is to determine the role of High Sensitivity Troponin I (hs-cTnI),measured at diagnosis, for the prediction of mortality and cardiac disease in long term follow-up of patients with IM. Methods: A observational cohort study involving patients diagnosed with IM will be carried out at the outpatient clinic of Inflammatory Myopathies of the Rheumatology Service of the Clinics Hospital, University of Sao Paulo Medical School (HC / FMUSP) - São Paulo. Patients will be selected according to the availability of serum samples stored at -80ºC in the Laboratory of Inflammatory Myopathies of the Rheumatology Department of the University of Sao Paulo Medical School, between 2009-2016. The following patient information will be obtained from electronic medical records: demographics, clinical-laboratory, treatment, presence of comorbidities, cardiovascular symptoms and signs on admission, electrocardiogram and echocardiogram of admission, follow-upanalysis (each 3-6 months). Patients with diagnosis on suction of muscular dystrophy, immune-mediated necrotizing myopathy, myositis by inclusion bodies, metabolic myopathies, myositis associated with other collagenases (overlaps), myositis associated with neoplasias will be excluded. At the time of the first medical consultation of patients in the Inflammatory Myopathy Unit (HC/ FMUSP), in addition to the electroneuromyography and muscle biopsy tests, routine laboratory tests related to the IM are also requested, which include: Muscle enzyme creative kinase, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and aldolase, myositis-specific and myositis-associated antibodies. A further serum/plasma sample of patients (20mL of blood) is also routinely collected during the study period for additional diagnostic investigation of myositis-specific and myositis-associated autoantibodies performed at the Laboratory of Inflammatory Myopathies for the purpose of diagnostic complementation of patients. The purpose of this projects to use these stored samples at - 80ºC, thus allowing an eventual correlation between the potential biomarkers proposed and the clinical and/or prognostic evolution of the patients analyzed. High sensitivity troponin I will be dosed with the Abbott ARCHITECT STAT High Sensitive Troponin I® assay in the stocked serum/plasma, as previously mentioned. As there are no studies evaluating the relationship between biomarkers and cardiovascular events, and existing studies have evaluated different cardiac biomarkers in a relatively small sample of patients (between 11 and 76 patients), we will carry out a study Pilot study with 200 patients from the Ambulatory of Inflammatory Myopathies(HC/FMUSP). Results will be presented as medians and interquartile range or mean and standard deviation for continuous variables and numbers (%) for categorical variables. P value <0.05 will be considered significant. Patients with altered biomarkers will be compared with those with normal biomarkers regarding the clinical characteristics and outcome.