Epidemiological study on atrial fibrillation among aged members of a Japanese community

AIM: 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. CONCLUSION: 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.