DESCRIPTIVE EPIDEMIOLOGY OF IDIOPATHIC DILATED CARDIOMYOPATHY IN WASHINGTON COUNTY, MARYLAND, 1975-1991

Estimates of the incidence of idiopathic dilated cardiomyopathy (IDC) were obtained by identifying cases from Washington County, Maryland wh o were hospitalized at local and regional hospitals over a recent 17 y ear period. All of the verified cases had evidence of ventricular dila tation and hypokinesis, with a left ventricular ejection fraction of l ess than 40%. A total of 26 cases were hospitalized over the period 19 75-1991. The average age of the cases at the time of diagnosis was 55. 5 years (range 22-80 years of age). About 58% of the subjects were mal es. A marked increase in newly diagnosed cases of IDC occurred in this population in recent years; 38% of the cases (10 of 26) were newly di agnosed during 1991 alone. Over the period 1975-1991, the average annu al incidence rate of hospitalized cases was 1.6 per 100,000 among men and 1.2 per 100,000 among women. During the last 7 years of the case a scertainment period (1985-1991), the average annual incidence rate was 3.5 per 100,000 among men and 2.5 per 100,000 among women. These resu lts provide additional evidence that IDC is being increasingly recogni zed by clinicians, and underscore the need for an improved understandi ng of the distribution and determinants of this often fatal condition.