Towards risk factor assessment in inflammatory dilated cardiomyopathy: the SFB/TR 19 study

BACKGROUND: Patients with idiopathic dilated cardiomyopathy (DCMid) account for about one-third of patients with heart failure. Recent studies found a myocardial viral genomic persistence in up to 67% of DCMid patients, indicating a possible inflammatory etiology (DCMi). Considering the importance of DCMi, we aimed to study the present knowledge on risk factors in DCMi. METHODS: Review of published literature on risk factors for DCMi/DCMid from 1989 through 2005 in Medline database and the Cochrane library (search terms 'epidemiology', 'risk factors', 'inflammatory dilated cardiomyopathy' and 'idiopathic dilated cardiomyopathy'). RESULTS: An extended array of risk factors in DCMid has been investigated in 11 studies. No studies addressing specifically DCMi, however, were found. Consistent associations with DCMid were reported only for diabetes mellitus, black race, male sex and estimated low income. Inconsistent results were observed for the presence of asthma, hypertension and smoking. Few studies addressed potential risk factors such as low education level, infectious diseases and environmental factors. CONCLUSIONS: Considering the high number of potential DCMi patients among patients with DCMid, results on risk factors for DCMid are likely relevant to at least a number of patients with DCMi. Future studies of risk factors in DCMi should include specific case classification and the application of standardized instruments for risk-factor assessment. The four-center SFB/TR 19 study aims to establish a prospective cohort of DCMi patients validated by endomyocardial biopsy.