Prognosis and prognostic factors in patients with idiopathic dilated cardiomyopathy in Japan.

BACKGROUND There have been few large-scale nationwide studies investigating both the prognosis and the prognostic factors of idiopathic dilated cardiomyopathy (IDC). A predictive score that can be used in clinical practice has not been established. METHODS AND RESULTS A nationwide epidemiological study of the prognosis of IDC was conducted in 1999 among randomly selected hospitals in Japan, and 147 departments participated in the present 5-year follow-up survey. The vital status of 1,554 IDC patients was collected in 2004 using medical records and residence-based registers. The crude 5-year survival rate for those diagnosed in 1998 was 78.6%. Cox's regression model selected 5 independent predictors of mortality: male sex, higher age, higher New York Heart Association functional class, higher left ventricular diameter index, and lower left ventricular ejection fraction. A predictive score using these 5 variables effectively predicted prognosis; 5-year survival rates were 90.6% in patients with a score of 4 or less and 49.0% in patients with a score of 9 or 10. CONCLUSIONS This nationwide survey revealed the present prognostic status of IDC in Japan and 5 independent predictors of prognosis that can be used in clinical practice as a predictive score.