Background Dilated cardiomyopathy (DCM) has been suggested to be a consequence of a prior viral infection leading to a chronic inflammatory and immunological reaction that leads to a structural and functional deterioration of the heart. Nevertheless, the results of present studies are conflicting, regarding the natural course of heart diseases associated with detection of viral genome and inflammation. On the other hand, diabetes mellitus (DM) is the leading endocrine disorder worldwide and sufficient to induce a cardiomyopathy. It is not known whether DM contributes to the clinical picture of cardiomyopathy associated with the presence of viral genome or inflammatory cells in the myocardium. Therefore, the present study was undertaken to compare histological, immunohistochemical, biochemical, and functional data as well as the outcome of patients presenting with DCM and positive for DM with patients negative for DM to evaluate for a diabetic contribution in the course of the disease. Methods A total of 216 patients were biopsied between January 1998 and April 2003. From 197 patients diagnosed as having DCM, we were able to complete data set regarding the presence of DM in 108 patients, 20 patients with and 88 patients without DM. Results There was no significant difference regarding age, gender, body mass index, presence of viral genome and inflammatory cells in the myocardium, left ventricular function and diameter, and the degree of heart insufficiency. There was a significant difference of apoptotic cells in the myocardium of patients with DCM and DM compared to patients with DCM alone (1.7+/-1.9 vs. 0.2+/-0.4, p=0.028). During the follow-up of 16 months, left ventricular function improved in both groups significantly, but not between the groups. Death or transplantation-free survival was not significantly different. Conclusion The different findings regarding the presence of apoptotic cells suggest a contribution of pathobiological pathways in the patients with DM to the underlying heart disease.
