[Epidemiological study on atrial fibrillation among aged members of a Japanese community].
OBJECTIVE
Epidemiological studies on atrial fibrillation (AF) in Japanese is scarce. As aging is one of the contributing factors to AF, we investigated the prevalence of AF among aged members of a Japanese community.


METHODS
Samples were community residents who were aged 65 years or older from town I, which is located at the north end of Kyoto Prefecture, Japan, and 39.9% of the population is over age 65 years old. For a period of 22 months starting in March, 2006, three groups of residents were evaluated: out-patients of the community clinic (the patients group); those who participated in annual residents' check up including ECG (the check-up group) and residents who visited clinics for influenza vaccinations (the pulse-examination group).


RESULTS
This study screened 550 patients (81.2% of residents more than 65 years old) in the jurisdiction of the town clinic. A total of 44 residents were diagnosed as having AF, that is 8.0% of residents screened over 65 years old in town. This resulted in a prevalence of 6.5% among all residents over 65 years old. Patient's age ranged from 65 to 94 years old. The male to female ratio was 0.58: 1 and chronic AF was 52.3%. There were 42 subjects with AF out of 419 in the patients group, 2 subjects with AF out of 97 in the check-up group, and no subjects with AF in the pulse-examination group. Among the 42 subjects with AF in the patients group, 88.1% had non-valvular AF and 71.4% had hypertension. Eight patients (19%) suffered from brain infarction and transient ischemic attack, and ten had non-symptomatic AF (23.8%). Among this group, 37.8% had a CHADS2 score above 3. Twenty-three patients (54.8%) received anti-coagulation medication and 15 (35.7%) received anti-arrhythmic medication.


CONCLUSIONS
The prevalence of atrial fibrillation among elderly patients in a community in Japan was 8.0%. This group has a high risk of brain infarction. As nearly 24% of patients had non-symptomatic AF, it is important to keep non-symptomatic AF in mind in the treatment of the elderly in order to improve their ADL and QOL.
Imanaka
Shunji
S
Ine Cho National Health Insurance Ine Clinic.
D000368:Aged; D001281:Atrial Fibrillation / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male