Risk of cardiovascular and cerebrovascular events after atrial fibrillation diagnosis☆
Introduction
Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting approximately 1% of the total adult population [1] increasing to 9% in individuals over 80 years old [2]. Diabetes, hypertension, congestive heart failure and valve disease, among others, are independent risk factors for AF [3]. Several studies have previously reported an adverse prognosis of AF patients in terms of stroke, congestive heart failure and mortality [4], [5], [6]. Mortality from AF is especially high in the first four months after diagnosis [7], but AF is also associated with a long-term elevation in mortality, with the death rate among patients newly diagnosed with chronic AF being almost three times that in the general population during four years of follow-up [8]. The major cause of excess mortality among patients with chronic AF is non-ischemic heart disease, with ischemic cardiovascular and cerebrovascular disease also making a contribution. Thus, while the main burden known to be associated with AF is an increased risk of ischemic cerebrovascular events (ICVE) [4], [8], AF is also common in patients with severe chronic heart failure (HF) [2], [4], although this association is not as well characterized [9]. The association of AF with other subsequent arterial thrombotic disorders such as coronary events (CE) remains unclear.
The aims of the present study were to assess the incidence of further cardiovascular events (ICVE, CE and HF) in patients with a first diagnosis of AF and free of ICVE, CE or HF at baseline, and to evaluate the role of traditional risk factors for ICVE, CE and HF in AF patients.
Section snippets
Data source
The UK General Practice Research Database (GPRD) contains computerized information entered by primary care physicians in the UK. The vast majority of the UK population is registered with a primary care physician. At the time of the study, around 1500 physicians were participating in the GPRD, covering a population of around 3 million individuals broadly representative of the UK population. The primary care physicians hold the complete medical record of registered individuals, including
Results
The AF and comparison groups consisted of 831 and 8226 patients, respectively. The characteristics of both study groups at the start of follow-up are shown in Table 1. Patients were followed for a maximum of 6 years (mean 3.6 ± 1.5 years). During this period, 261 patients in the AF group and 622 in the control group had a first diagnosis of a cardiovascular event, equating to an incidence of 11.1 per 100 patient-years (95% confidence interval [CI]: 9.9–12.5) in the AF group and 2.1 per 100
Discussion
This study found that a first diagnosis of AF significantly increased the subsequent risk of new cardiovascular events compared with patients without AF. This risk was particularly increased in older patients and those with diabetes or other cardiovascular diseases as indicated above, and was greater in patients with CAF than those with PAF. A worse prognosis among patients with CAF has been seen in previous studies. For example, in a study of 145 patients with lone AF, 30.6% of patients with
Acknowledgements
We would like to thank Dr Hector Bueno of Gregorio Marañon University Hospital, Madrid, Spain for his helpful suggestions to prior versions of the manuscript. We also thank Dr Christopher Winchester of Oxford PharmaGenesis Ltd for his editorial assistance. This study was supported by a research grant from AstraZeneca and was presented at the World Congress of Cardiology 2006.
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Disclosures: this study was funded by a research grant from AstraZeneca R&D Mölndal, Sweden. Dr Wallander, Dr Johansson and Dr Edvardsson are employees of AstraZeneca. Dr Ruigómez and Dr García Rodríguez work for CEIFE, which has received research grants from AstraZeneca. The corresponding author had full access to all the data in the study, and takes responsibility for the integrity of the data and the accuracy of the data analysis.