Troponin in diabetic patients with and without chronic coronary artery disease

Carlos Alexandre Wainrober Segre, Whady Hueb, Rosa Maria Rahmi Garcia, Paulo Cury Rezende, Desiderio Favarato, Celia Maria Cassaro Strunz, Marília da Costa Oliveira Sprandel, Alessandra Roggério, Ana Luiza de Oliveira Carvalho, Raul Cavalcante Maranhão, José Antonio Franchini Ramires, Roberto Kalil Filho

Cardiac-specific troponin detected with the new high-sensitivity assays can be chronically elevated in response to cardiovascular comorbidities and confer important prognostic information, in the absence of unstable coronary syndromes. Both diabetes mellitus and coronary artery disease are known predictors of troponin elevation. It is not known whether diabetic patients with coronary artery disease have different levels of troponin compared with diabetic patients with normal coronary arteries. To investigate this question, we determined the concentrations of a level 1 troponin assay in two groups of diabetic patients: those with multivessel coronary artery disease and those with angiographically normal coronary arteries. We studied 95 diabetic patients and compared troponin in serum samples from 50 patients with coronary artery disease (mean age = 63.7, 58 % male) with 45 controls with angiographically normal coronary arteries. Brain natriuretic peptide and the oxidative stress biomarkers myeloperoxidase, nitrotyrosine and oxidized LDL were also determined. Diabetic patients with coronary artery disease had higher levels of troponin than did controls (median values, 12.0 pg/mL (95 % CI:10-16) vs 7.0 pg/mL (95 % CI: 5.9-8.5), respectively; p = 0.0001). The area under the ROC curve for the diagnosis of CAD was 0.712 with a sensitivity of 70 % and a specificity of 66 %. Plasma BNP levels and oxidative stress variables (myeloperoxidase, nitrotyrosine, and oxidized LDL) were not different between the two groups. In a multivariate analysis, gender (p = 0.04), serum glucose (0.03) and Troponin I (p = 0.01) had independent statistical significance. Troponin elevation is related to the presence of chronic coronary artery disease in diabetic patients with multiple associated cardiovascular risk factors. Troponin may serve as a biomarker in this high-risk population. http://www.controlled-trials.com Registration number: ISRCTN26970041.