Predisposing factors and incidence of newly diagnosed atrial fibrillation in an urban African community: insights from the Heart of Soweto Study.
BACKGROUND
Little is known about the incidence and clinical characteristics of newly diagnosed atrial fibrillation/flutter (AF) in urban Africans in epidemiological transition.


METHODS
This observational cohort study was carried out in the Chris Hani Baragwanath Hospital in Soweto South Africa. A clinical registry captured detailed clinical data on all de novo cases of AF presenting to the Cardiology Unit during the period 2006-2008.


RESULTS
Overall, 246 of 5328 cardiac cases (4.6%) presented with AF (estimated 5.6 cases/100 000 population/annum). Mean age was 59±18 years and the majority were of African descent (n=211, 86%) and/or female (n=150, 61%). Men were more than twice as likely to smoke (OR 2.88, 95% CI 1.92 to 4.04) than women, but women were twice as likely to be obese (OR 1.80, 95% CI 1.28 to 2.52) than men. Lone AF occurred in 22 (8.9%) cases, while concurrent valve disease and/or functional valvular abnormality occurred in 107 cases (44%). Overall, 171 cases (70%) presented with uncontrolled AF (ventricular rate >90 beats/min) with no sex-based differences. Common co-morbidities were any form of heart failure (56%) and rheumatic heart disease (21%). Women with AF were more likely to present with hypertensive heart failure (OR 2.37, 95% CI 1.24 to 4.54) but less likely to present with a dilated cardiomyopathy (OR 0.42, 95% CI 0.23 to 0.76) or coronary artery disease (OR 0.38, 95% CI 0.14 to 1.02) than men. Mean overall CHADS(2) score (in 195 non-rheumatic cases) was 1.51±0.91 and, despite a similar age profile, women had higher scores than men (1.73±0.94 vs 1.24±0.78; p<0.0001).


CONCLUSIONS
These unique data suggest that urban Africans in Soweto develop AF at a relatively young age. Conventional strategies used to manage and treat AF need to be carefully evaluated in this setting.
Preventative Health, Baker IDI Heart and Diabetes Institute, St Kilda Rd. Central, Melbourne, Vic 8008, Australia.
Karen
K
Sliwa
Melinda Jane
MJ
Carrington
Eric
E
Klug
Lionel
L
Opie
Geraldine
G
Lee
Jocasta
J
Ball
Simon
S
Stewart
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000453:epidemiology*; D001282:Atrial Flutter / Q000188:drug therapy / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D017678:Sex Distribution; D013019:South Africa / Q000453:epidemiology; D013923:Thromboembolism / Q000453:epidemiology / Q000209:etiology; D014504:Urban Health; D055815:Young Adult
D000889:Anti-Arrhythmia Agents