Elsevier

International Journal of Cardiology

Volume 205, 15 February 2016, Pages 127-132
International Journal of Cardiology

Prevalence, incidence, risk factors and treatment of atrial fibrillation in Australia: The Australian Diabetes, Obesity and Lifestyle (AusDiab) longitudinal, population cohort study

https://doi.org/10.1016/j.ijcard.2015.12.013Get rights and content

Abstract

Objective

We sought to describe the prevalence, incidence, risk factors and treatment (according to stroke risk) of atrial fibrillation (AF) in the national, population-based Australian Diabetes, Obesity and Lifestyle (AusDiab) study cohort.

Methods

ECG data were available from 8273/11,247 participants of AusDiab study in 1999/2000 and from 5422 participants in 2004/2005. Minnesota coding was used to identify prevalent and incident cases of AF.

Results

90 prevalent cases of AF (14.1 per 1000) comprising 56 men (mean age 70.5 ± 1.9 years) and 34 women (aged 78.3 ± 1.2 years) were identified in 1999–2000. AF prevalence was associated with sedentary behaviour versus physically active (PR 2.0, 95% CI 1.2–3.6). 53 incident cases of AF (2.0, 95%, CI 1.5–2.6 per 1000 person–year) were subsequently identified in 2004–2005. Increased risk of incident AF was associated with male sex, obesity, history of angina, myocardial infarction and stroke. Both increased weight gain and increased weight loss appeared to be associated with increased risks of developing AF in women, while no obvious association was observed in men. Despite their high risk for stroke, anti-thrombotic therapy was observed in only 39.3% of participants with CHA2DS2-VASC scores  2.

Conclusions

This study contributes to a better understanding of the AF burden. With the ageing population, coordinated efforts will be needed to anticipate the future health care costs related to AF and its impacts on the health care system. This will include appropriate application of anti-thrombotic therapy according to risk of thrombo-embolic events.

Introduction

Affecting more than 33 million individuals in the world [1], atrial fibrillation (AF) is the most common cardiac arrhythmia and one of the most common cardiac conditions overall [2]. As originally confirmed by the Renfrew–Paisley study cohort in Scotland, independent of other factors, AF is not a benign condition in respect to conveying a markedly higher risk of long-term mortality [3]. In particular, AF is associated with increased risks of morbidity and mortality from complications including stroke, other embolic complications and heart failure [4], [5], [6]. The worldwide burden of AF is increasing, with more than 5 million new cases each year [1]. Ball et al. estimated that without any changes in incidence of AF or survival rates in patients with AF, the number of individuals affected by AF in Australia will double between 2014 and 2034 (300,000 to 600,000) [7]. The lack of Australian data on AF prevalence and incidence mainly explains why Ball and colleagues applied international AF prevalence statistics to the Australian adult population aged ≥ 55 years to estimate the current and potential future prevalence of AF in Australia [7]. Although hospital admissions data may provide useful information on the predictors and outcomes associated with AF [8], they may be limited in describing the broader epidemiology of AF.

With AF becoming a greater public health burden, AF prevalence and incidence figures as well as predictors of AF in the Australian population are urgently needed to facilitate future health care planning. Using data from the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) [9], therefore, we sought to describe the epidemiology and risk factors of AF in this national, population-based cohort. Given the importance of prescribing anti-thrombotic therapy to prevent stroke in high risk individuals with AF (those with CHA2DS2-VASC  2) [10], we also sought to characterize the application of such therapy in identified cases of AF. To our knowledge, this is the first report on the prevalence, incidence and risk factors of AF derived from a national population-based sample of the Australian adult population.

Section snippets

Study population

The AusDiab study methods have been previously reported [9]. Briefly, AusDiab is a national, population-based survey of adults aged ≥ 25 years, with baseline examination in 1999–2000. Information was collected during a household interview and a subsequent biomedical examination. Of the 20,347 eligible people who completed a household interview, 11,247 (55.3%) attended for the biomedical examination including 55.1% of females [9]. Over 85% of the sample was born in Australia, New Zealand or UK,

Results

Among 8273 men and women aged ≥ 35 years who had ECGs at baseline, AF was found in 90 participants (a prevalence of 14.1 per 1000). Although the crude prevalence of AF was similar in men and women (14.6 per 1000 versus 13.6 per 1000 respectively), the pattern of age specific prevalence of AF was different in men compared to women. AF was more prevalent in men aged < 75 years compared to women of the same age group: age < 55 years (3.4 per 1000 versus 0.0 per 1000); 55–64 years (9.4 per 1000 versus 0.0

Discussion

This study is the first report on the prevalence, incidence and risk factors of AF derived from a national population-based sample of the Australian adult population. AF prevalence was associated with sedentary behaviour (sedentary versus physically active). Increased incidence of AF was associated with male sex, obesity and prior history of angina, myocardial infarction and stroke. Both increased weight gain and increased weight loss appeared to be associated with increased risks of developing

Conclusion

This study contributes to a better understanding of the AF burden. AF is a disease of the elderly and with the ageing population, its impact will be largely amplified in the next decades. Co-ordinated efforts will be needed to anticipate its future health care costs and its impacts on the health care system. Future challenges will also include appropriate application of anti-thrombotic therapy according to risk of thrombo-embolic events.

Conflict of interest

No relevant disclosures.

Acknowledgements

We are most grateful to the following for their support of the study: Commonwealth Dept. of Health and Aged Care, Abbott Australasia Pty Ltd., Alphapharm Pty Ltd., AstraZeneca, Aventis Pharmaceutical, Bristol-Myers Squibb Pharmaceuticals, Eli Lilly (Aust) Pty Ltd., GlaxoSmithKline, Janssen-Cilag (Aust) Pty Ltd., Merck Lipha s.a., Merck Sharp & Dohme (Aust), Novartis Pharmaceutical (Aust) Pty Ltd., Novo Nordisk Pharmaceutical Pty Ltd., Pharmacia and Upjohn Pty Ltd., Pfizer Pty Ltd., Roche

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  • Cited by (0)

    1

    These authors take responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.

    2

    These authors participated to the interpretation of the results and the redaction of the manuscript.

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