PREDICTORS OF CORONARY ANGIOGRAPHY IN PATIENTS WITH IDIOPATHIC DILATED CARDIOMYOPATHY - THE WASHINGTON, DC DILATED CARDIOMYOPATHY STUDY

Although a number of clinical and demographic factors have been associ ated with the performance of angiography in cardiac patients, clinical studies of idiopathic dilated cardiomyopathy (DCM) have often exclude d patients who have not undergone coronary angiography to rule out cor onary artery disease (CAD). To examine the impact of this diagnostic c riterion on population-based studies of idiopathic DCM, we examined ch aracteristics of probable cases of DCM who did or did not have a recor ded history of angiography. The cases (n = 129) were ascertained from five medical centers in the Washington, DC metropolitan area over the period 1 July 1990 through 29 February 1992. All of these cases had ev idence of ventricular dilation and hypokinesis, with a left ventricula r ejection fraction of less than 40%. Cases with a history of known CA D, congenital heart disease, valvular heart disease, or secondary card iomyopathy were excluded. Sixty-two (48%) of the cases had a recorded history of angiography. Age, educational level, diabetes, alcohol use, insurance status, and type of hospital were significantly associated with angiography in bivariate analysis (p < 0.05). Diabetes and hypert ension were inversely associated with history of angiography among bla ck cases, and positively associated with angiography among whites. In logistic regression analysis, age was the strongest independent predic tor of angiography (p < 0.025). The associations with educational atta inment and alcohol use were of borderline significance (p < 0.10). Thu s, in epidemiologic studies of idiopathic DCM, particularly in biracia l populations, the exclusion of cases who have not undergone angiograp hy may bias risk estimates and result in the underestimation of incide nce and prevalence.