BEIJING, CHINA. It is estimated that 2.5 million people in the USA and 4.3 million individuals in the EU suffer from atrial fibrillation (AF). Up until now, it has not been clear whether AF is a disease related to Western civilization and lifestyle, or whether it is a worldwide phenomenon. Chinese researchers now provide a partial answer. A large-scale epidemiological study involving more than 29,000 individuals from 13 provinces and 14 ethnic groups in China found an age-adjusted AF rate of 0.61%, suggesting that approximately 8 million adults in China have AF. This prevalence is very similar to that observed in the USA and Europe, thus pretty well laying to rest the idea that AF is somehow related to Western lifestyle and diet.
The Chinese researchers confirmed that the risk of AF increases with age and is more prevalent among men. The percentages of nonvalvular AF, valvular AF, and lone AF were 65%, 13%, and 22% respectively. Hypertension and heart failure were the most common underlying comorbidities in hospitalized AF patients – the majority (76%) of whom had nonvalvular AF with the remaining 24% having valvular AF. Thus, it would appear that lone afibbers are not hospitalized in China.
The incidence of ischemic stroke was high among non-hospitalized individuals with AF at a rate of 12.1% a year vs. 2.1% a year in the general population. Among hospitalized patients with nonvalvular AF, the rate was even higher and dramatically dependent on age. Thus, the average incidence was 4.3% in patients younger than 40 years, but almost 33% in those 80 years of age or older. The main risk factors for stroke in hospitalized patients were found to be hypertension, high systolic blood pressure, diabetes, left atrial thrombi, and age at or above 75 years.
The epidemiological study found that only 2.7% of AF patients were on warfarin and none had their INR monitored on a regular basis. A study involving 828 patients with nonvalvular AF found that warfarin therapy was twice as effective as aspirin therapy (150 – 160 mg/day) in preventing ischemic stroke.
Hu, D and Sun, Y. Epidemiology, risk factors for stroke, and management of atrial fibrillation in China. Journal of the American College of Cardiology, Vol. 52, No. 10, September 2, 2008, pp. 865-68