WHAT EXPLAINS BLACK-WHITE DIFFERENCES IN SURVIVAL IN IDIOPATHIC DILATED CARDIOMYOPATHY - THE WASHINGTON, DC, DILATED CARDIOMYOPATHY STUDY

We have Found race to be an independent predictor of mortality in a pr eliminary analysis of data from an ongoing study of patients with idio pathic dilated cardiomyopathy. Our previous analyses, however, were ba sed on only 12 to 24 months of follow-up. In the present analysis, whi ch is based on up to 5 years of follow-up, we extended our earlier obs ervations and examined whether other socioeconomic factors account For the association with race. A total of 128 patients from five Washingt on, DC, area hospitals were included in the analysis. One hundred thre e (80.5%) of the patients were black and 25(19.5%) were white. The bla ck patients were less likely to have private health insurance, less ed ucated on average, and more likely to-have a household income less tha n or equal to$15,000. No racial differences were found in cardiac medi cation usage, with the exception of beta blockers and antiarrhythmics. The cumulative survival among black patients at 12 and 60 months was 71.5% and 39.1%, respectively compared with 92% and 31.4% among whites . Age, ventricular arrhythmias, and election fraction were significant predictors of survival in univariate analysis. The univariate associa tion with black race was of borderline significance. In multivariable analysis using the proportional hazards model, age and election fracti on were significant independent predictors of survival. The associatio n with ventricular arrhythmias was of borderline significance. The ass ociation with black race, which was statistically nonsignificant, was diminished even further by adjustment for income and type of health in surance. Thus,the previously reported association with black race may be accounted For by socioeconomic factors related to access to health care.