A community based epidemiological and clinical study of hospitalization of patients with congestive heart failure in Northern Iwate, Japan

Abstract

Background: Community based studies of congestive heart failure (HF) are lacking in the Japanese population. Methods and Results: To delineate the epidemiological and clinical features of advanced HF in the general Japanese population, hospitalized adult cases of HF in all hospitals within the Ninohe district were registered for 3 years. During the survey period, 190 new onset cases (males n=93; females n=97) and a total of 391 hospitalizations (including repeat admissions) were registered. The prevalence of atrial fibrillation in new HF cases was 56% in males and 45% in females. On the basis of the population of the district, the incidence of hospitalized HF was 96 in males and 92 in females per 100,000 person-years. The percentage of HF patients who were ≥65 years of age was 82% in males and 94% in females. In cases undergoing echocardiography, preserved left ventricular systolic function (left ventricular ejection fraction ≥50%) was observed in 29% of males and 41% of females. There was a significant seasonal variation in HF admissions (Spring 32%; Summer 20%; Autumn 20%; Winter 28%; p<0.01). Conclusions: In comparison with published results of USA and European community based studies of HF, the present HF cohort showed that: (1) mean age, prevalence of preserved ejection fraction, and trends in seasonal variation were comparable; however (2) the incidence of HF was obviously lower. These epidemiological and clinical characteristics should be taken into consideration when establishing a therapeutic and preventive approach for HF.