Epidemiology of Idiopathic Dilated Cardiomyopathy (Washington, DC Dilated Cardiomyopathy Study)

BACKGROUND:

Idiopathic dilated cardiomyopathy is an often fatal cause of heart failure in young adults which is characterized by dilatation of the ventricles, increased myocardial mass, and impairment of systolic function. Dilated cardiomyopathy is more common than hypertrophic and restrictive cardiomyopathy, and the symptoms and physical signs are those of left-sided and eventually right-sided heart failure. Histologic findings in the condition include nonspecific interstitial myocardial fibrosis and myocyte hypertrophy. Despite the large number of systemic or generalized disease processes which have been associated with secondary dilated cardiomyopathy, the majority of cases are idiopathic. Mortality rates from cardiomyopathy have increased dramatically since 1970, and in 1990 over 10,000 deaths annually were attributed to cardiomyopathy in the United States.

DESIGN NARRATIVE:

The study had a prospective case-control design. Medical records of possible cases of idiopathic dilated cardiomyopathy who were discharged from five Washington, D. C. acute care hospitals over a two year period were abstracted so that standard diagnostic criteria could be applied. Two neighborhood controls were identified for each case. Cases and controls were matched on five year age intervals, sex, and telephone exchange. Cases were contacted annually during the two to three year follow-up period to determine vital status. The study determined whether the reported association between idiopathic dilated cardiomyopathy and asthma could be confirmed and the possible role of asthma medications, cigarette smoking, moderate alcohol consumption, and diabetes mellitus in the etiology of idiopathic dilated cardiomyopathy. The role of hypertension was also studied.. Statistical analysis consisted of case-control comparisons using conditional logistic regression techniques, and survival analyses using Kaplan-Meier curves and proportional hazards models.

The study was also known as the Washington, D.C. Dilated Cardiomyopathy Study. Dr. Coughlin started his research at Georgetown University in Washington, D.C. and transferred to Tulane University.