[A population-based study on incidence of idiopathic cardiomyopathy in Nanjing, 1985-1989]

The epidemiology of idiopathic cardiomyopathy (ICM) is largely unknown among Chinese population. The purpose of this study was to document the incidence of ICM in the entire residents aged less than 60 years in Nanjing city during the five year period from 1985 to 1989. Using the case registered method it was identified that 275 new cases of ICM collecting from all of the clinically diagnosed outpatients and inpatients in the 14 related hospitals within the city among 2,098,175 residents for years 1985-1989. Over all incidence rate was 2.6 per 100,000 person-years, the age-and sex-adjusted average annual rate being 2.1 per 100,000 directly according to the standardized population of China in 1964 (95% confidence interval 1.9-2.2). This incidence rate was increased from 1.7 per 100,000 in 1985 to 3.3 per 100,000 in 1989 and progressively increasing with aging especially in the groups over 20 years old. Among these 275 patients with ICM, 134 were classified to idiopathic dilated cardiomyopathy (IDCM) and 132 to idiopathic hypertrophic cardiomyopathy (IHCM). Both the average annual incidence rates of IDCM and IHCM were 1.3 per 100,000 and the age-and sex-adjusted rates were 1.1 per 100,000 (95% CI 0.9-1.2) in IDCN and 0.9 per 100,000 (95% CI 0.8-1.0) in IHCM, respectively. The incidence rate of ICM in male was 3.0 significantly higher than 2.2 per 100,000 in female especially in IHCM. The result of this survey is first provided with incidence data of ICM on a broad general population-based study in our country and may be of value in further studying its epidemiology and etiology.