Risk factors for atrial fibrillation in Ibadan, Nigeria: A case-controlled study

Atrial fibrillation (AF) is a common arrhythmia that is a potent independent risk factor for stroke. The incidence of AF increases with age, and most affected people have underlying cardiac disease. This study aimed to describe the risk factors for AF in Nigeria.

This was a hospital-based case-controlled study. The cases were adult male and female clinic attendees aged 18 years and above who had 12-lead ECG-diagnosed atrial fibrillation. They were age- and sex-matched with clinic attendees who were free of AF. A uniform case report form was used for data collection for the cases and controls. These included: socio-demographic, clinical history, cardiovascular risk factors and co-morbidities, symptoms and signs, laboratory, 12-lead ECG, and echocardiography data.

The mean age of the cases was 63.57 ± 4.59 years, while that of the control group was 63.21 ± 14.29 years. There were 114 and 101 males and females in each group. There were similarities in the socio-demographic characteristics. The pulse rate was significantly higher in the cases, but the blood pressure was significantly lower. Family history of CVD, cardiomyopathy, hypertension, myocardial infarction, congenital heart disease, rheumatic heart disease, and stroke were significantly more common in cases than in controls. The cases had lower packed cell volume, serum sodium, estimated glomerular filtration rate, plasma glucose, total cholesterol, low-density lipoprotein cholesterol, and triglyceride; as well as larger atria, thinner walls, and larger left ventricular internal dimensions. The independent risk factors associated with AF in the study were: left atrial dimension-aOR-6.49, 95% CI-2.05-20.51, p=0.001; left ventricular internal dimension in diastole-aOR=3.13, 95%CI, 1.03-9.52, p=0.044, eGFR-aOR-0.93, 95% CI-0.89-0.97, 0.001; total cholesterol- aOR=1.02, 95%CI, 1.00-1.03, p=0.044 and, HDL cholesterol aOR=0.94, 95%CI, 0.91-0.98, p=0.001 CONCLUSION: The study identified left atrial dimension, left ventricular internal dimension in diastole, eGFR, total cholesterol, and HDL cholesterol as the independent predictors of AF. Stroke rates were also high in the AF population. Modification of these risk factors at the population level will prevent or delay the onset of AF. Appropriate management of AF cases, especially with anti-coagulation, will also prevent or reduce stroke incidences in them.