Diagnosed, undiagnosed and overall atrial fibrillation research on population over 60 year-old. AFABE study

Background: Undiagnosed atrial fibrillation usually is only detected with the first complication. We estimated undiagnosed Atrial Fibrillation prevalence, overall AF and associated factors in a public health-service area in Catalonia, north-eastern Spain. Methods: Multicentre, cross-sectional study, with people randomly selected among the attended population over 60 years old by primary care teams regardless of follow-up time in health centres or at homes. Information was collected through ECGs, electronic medical history reviews and medical interviews. Descriptive and logistic regression analysis was performed. Results: 1043 subjects were recruited (47.1% male), mean age: 73.1 y-o (SD: 7.8 y-o); 43.3% ≥75-year-old. Overall AF prevalence was 10.9% (CI95% 9.1-12.8%); higher in men than in women, progressively increasing with age (24.4% in ≥85-year-old). Only women ≥85-year-old had higher prevalence (26.2%) than men (22.5%). Undiagnosed AF relative prevalence was 2.2% (IC95% 1.3-3.1%). These results show that about 1 in 50 people over 60 years old could suffer undiagnosed AF. The higher risk of AF undiagnosed was found in: men (OR 2.5 IC95% 1.0-6.2), >75 years old (OR 2.5 IC95% 1.0-6.1), heart failure history (OR 5.2 IC95% 1.3-20.9), who live in rural areas (OR 15.9 IC95% 1.5-160.1) and to whom no one ECG was performed in the last two years. Conclusions: The overall AF prevalence increased 10 times from the sixties to over eighties and the proportion man-woman changes from 4:1 to 1:1. The undiagnosed AF prevalence was 2.2% (IC95% 1.3-3.1). This percentage should be added to the one of untreated cases with OAC.