Correlates and consequences of atrial fibrillation in a prospective study of 25,000 participants in the China Kadoorie Biobank

The prevalence of atrial fibrillation (AF) is positively correlated with prior cardiovascular diseases (CVD) and CVD risk factors, but is lower in Chinese than Europeans despite their higher burden of CVD. We examined the prevalence and prognosis of AF and other ECG abnormalities in the China Kadoorie Biobank. A random sample of 25,239 adults (mean age 59.5 years, 62% women) had a 12-lead ECG recorded and interpreted using a Mortara VERITAS™ algorithm in 2013-2014. Participants were followed-up for 5 years for incident stroke, ischaemic heart disease (IHD), heart failure (HF) and all CVD, overall and by CHA2DS2-VASc scores, age, sex, and area. Overall, 1.2% had AF, 13.6% had left ventricular hypertrophy (LVH), and 28.1% had ischaemia (two-thirds of AF cases also had ischaemia or LVH). The prevalence of AF increased with age, prior CVD and levels of CHA₂DS₂-VASc scores (0.5%, 1.3%, 2.1%, 2.9%, and 4.4% for scores <2, 2, 3, 4,  ≥ 5, respectively). AF was associated with 2-fold higher hazard ratios (HR) for CVD (2.15; 95% CI, 1.71–2.69) and stroke (1.88; 1.44–2.47), and a 4-fold higher HR for HF (3.79; 2.21–6.49). The 5-year cumulative incidence of CVD was comparable for AF, prior CVD and CHA₂DS₂-VASc scores ≥2 (36.7% vs 36.2% vs 37.7%, respectively), but was 2-fold greater than for ischaemia (19.4%), LVH (18.0%) or normal ECG (14.1%), respectively. The findings highlight the importance of screening for AF together with estimation of CHA₂DS₂-VASc scores for prevention of CVD in Chinese adults.