Risk of cardiovascular and cerebrovascular events after atrial fibrillation diagnosis

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Abstract

Background

Atrial fibrillation (AF) is associated with subsequent cardiovascular events including ischemic stroke, transient ischemic events, and coronary events. This study aimed to evaluate the risk of ischemic cerebrovascular events (ICVE), coronary events (CE) or heart failure (HF) following a diagnosis of AF.

Methods

Patients were selected from the UK General Practice Research Database. The incidence of ICVE, CE and HF was determined during a 6-year follow-up period for patients with a first diagnosis of AF (n = 831) and a control group without AF (n = 8226). Relative risk of developing a cardiovascular event associated with prior AF and other potential risk factors was estimated using Cox regression analysis.

Results

A first diagnosis of ICVE, CE or HF was made in 261 patients in the AF group and 622 in the control group. The relative risks associated with AF were 2.1 for CE (95% CI: 1.6–2.9), 3.0 for ICVE (95% CI: 2.3–4.0) and 6.4 for HF (95% CI: 5.0–8.3). The risks of CE, HF and ICVE were higher in patients with chronic AF than paroxysmal AF (odds ratio: 1.5, 95% CI: 1.0–2.2) and in patients aged at least 60 years or with diabetes. Lifestyle factors did not significantly affect the risk of cardiovascular events in patients with AF.

Conclusions

After a first episode of AF there is an increased risk of ICVE, CE and HF. Patients initially diagnosed with chronic AF have a higher risk than those with paroxysmal AF.

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.

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