Summary
The prevalence of atrial fibrillation is steadily increasing throughout the world because of ageing populations and better management of coronary heart disease. An international literature review was conducted to estimate the prevalence and incidence of atrial fibrillation in France. A review of the literature on comorbidities was also performed. Finally, French mortality and hospitalization data were analysed using the PMSI database. The prevalence of atrial fibrillation is estimated to be between 600,000 and 1 million people; of these, two-thirds are aged > 75 years. The incidence is estimated at between 110,000 and 230,000 new cases per year. In 2008, 412,000 hospitalized patients had a diagnosis of atrial fibrillation; this figure increased by 26% in the 3-year period between 2005 and 2008. These findings highlight the importance of targeting therapy, of upstream therapy, and of therapy that provides clear clinical and economic advantages over the well-established reductions already achieved in atrial fibrillation morbidity, mortality and cost. In addition, new prevention strategies should be developed, particularly secondary prevention strategies in patients with cardiovascular diseases.
Résumé
La fibrillation atriale (FA) est en augmentation constante dans le monde, du fait du vieillissement des populations et de la meilleure prise en charge de la pathologie coronaire. Une revue de littérature internationale a été réalisée pour estimer la prévalence et l’incidence de la FA en France. Une analyse des publications sur les comorbidités a également été réalisée, ainsi qu’une analyse des données françaises de mortalité et d’hospitalisations (PMSI). La prévalence de la FA est estimée entre 600 000 et un million de personnes, dont deux tiers de plus de 75 ans et l’incidence est estimée entre 110 000 et 230 000 nouveaux cas par an. En 2008, 412 000 patients hospitalisés ont eu un diagnostic de FA. Ce chiffre a augmenté de 26 % sur les trois années 2005–2008. Ces données soulignent l’importance de la prévention des maladies cardiovasculaires et du développement de thérapies ciblant la FA, avec des avantages clairement établis en termes d’efficacité clinique et de rapport bénéfice/risque, ainsi que le développement de stratégies de prévention secondaire chez les patients porteurs de maladie cardiovasculaire.
Abbreviations
AF
atrial fibrillation
CHF
congestive heart failure
CI
confidence interval
NYHA
New York Heart Association
PMSI
Programme for the Medicalization of Information Systems
Background
AF is the most common arrhythmia and is characterized by uncontrolled atrial activation and a subsequent deterioration of atrial mechanical function. Stroke and CHF are the most common complications in subjects with AF , and associated mortality rates are higher than in patients without AF .
Epidemiological surveys show that the risk of AF increases with age, particularly during the sixth and seventh decades of life . The increase in prevalence of AF over the past 50 years, due to the growing elderly population in industrialized countries, reflects this trend . The projected continued increase in the prevalence of AF is a cause of great concern, as this disease presents a major public health and socioeconomic burden . Targeting preventive healthcare and treatment for patients who are at risk is becoming an increasingly attractive option in order to reduce morbidity and control medical costs.
In this report, we carried out a systematic review of the literature to gather data on the prevalence and consequences of AF. Extrapolation of these data to French population statistics should enable us to better define the public health repercussions of AF in France and to identify specific target populations for monitoring and treatment. The incidence and prevalence of AF are not well known in France. A study by Guize et al. was published in 2007, but the study population was not representative of the general population .
Methods
Literature review
A literature review of published epidemiological studies in the field of AF was conducted using PubMed, with the following terms: ‘atrial fibrillation’ and ‘epidemiology’ or ‘prevalence’ or ‘incidence’ or ‘mortality’ or ‘comorbidity’. This literature review took into account only general population or community-based studies, which relate to the sampling of a geographical territory or of an administrative database, such as the Health Maintenance Organization in the USA or the General Practitioner database in the UK or other European countries. These studies cover all types of AF and the distinction between different types of AF is generally not detailed in the published articles or in the data sources.
Statistics
Data from international studies were used to extrapolate incidence and prevalence rates in the French population: the prevalence or incidence rates by age observed in the different studies were applied to the French population structure.
Analysis of French hospitalization data
Since 1991, public and private hospitals have been required to evaluate and analyse their activities. This analysis is based on the systematic collecting and computerized processing of minimal standardized medicoadministrative information contained in the standardized discharge case records, in a medicoeconomic database called PMSI.
The standardized discharge case record contains a limited amount of mandatory information: diagnoses (principal diagnosis and associated diagnosis) according to the International Classification of Diseases (ICD-10), procedures, related complications and/or morbidities and other information such as length of stay, patient’s age, etc.
An analysis of the PMSI database records for 2005–2008 was conducted for patients hospitalized for AF (as the principal or associated diagnosis).
Classification of atrial fibrillation
Several different classifications of AF can be found in the literature, complicating interstudy group comparisons . The following classification, dividing AF into one of four types based on the number and duration of episodes, is recommended by the current guidelines of the American College of Cardiology, the American Heart Association and the European Society of Cardiology : first detected episode of AF (symptomatic or asymptomatic); paroxysmal (self-terminating) AF, when an episode lasts ≤ 7 days and usually < 24 hours; persistent AF, when an episode lasts > 7 days, usually requiring termination by electrical or pharmacological cardioversion; permanent AF (previously referred to as chronic AF ), when AF fails to stop after cardioversion, or cardioversion is not attempted . Paroxysmal and persistent AF may both be recurrent (two or more episodes) and are often progressive. Approximately 8–9% of patients with paroxysmal AF progress to permanent AF within 1 year and 25% within 5 years . Higher rates of progression are observed in patients with persistent AF, with approximately 40% developing permanent AF by the end of the 1-year period .
The classifications have been defined for clinical research; they are very detailed and based on clinical features, so they are difficult to use in epidemiological studies.
Results
Prevalence of atrial fibrillation: international data
The prevalence of AF increases with age in both men and women ( Table 1 ) and approximately 70% of patients with AF are aged 65–85 years . In the general population aged > 60 years, the prevalence of AF is estimated to be below 1% . However, a meta-analysis of four large population-based surveys carried out in the USA, western Australia and Europe revealed that the prevalence of AF doubles with each decade of life after the age of 50 years, increasing to around 10% in individuals aged > 80 years . In another long-term, follow-up study of 3983 male aircrew recruits, the probability of developing AF over a 44-year follow-up period was 7.5% . These observations are supported by surveys conducted in the UK and Scotland . Murphy et al. recorded a prevalence of 9.4/1000 persons in men and 7.9/1000 in women, increasing to 71/1000 in subjects aged > 85 years ( Fig. 1 ).
| Study | |
|---|---|
| Meta-analysis of four USA studies | |
| Number of persons | 14,000 |
| Prevalence of atrial fibrillation (%) | |
| Overall | 0.89 |
| ≥ 40 years | 2.3 |
| ≥ 65 years | 5.9 |
| Median age (years) | 75 |
| Atrial fibrillation in California 1996–1997 (ATRIA study) | |
| Number of persons | 17,974 |
| Prevalence of atrial fibrillation (%) | |
| Overall (≥ 20 years) | 0.95 |
| 20–55 years | 0.1 |
| ≥ 60 years | 3.8 |
| ≥ 80 years | 9.0 |
| Median age (years) | 71.2 |
| ECG baseline study (Rotterdam study) | |
| Number of persons | 6808 |
| Prevalence of atrial fibrillation (%) | |
| Overall (≥ 55 years) | 5.5 |
| 55–59 years | 0.7 |
| ≥ 85 years | 17.8 |
A higher age-adjusted prevalence of AF has been documented consistently in men compared with in women . The age-adjusted risk of developing AF is also significantly higher in Caucasians than in Africans .
Asymptomatic AF has been reported in 11–32% of patients in different studies and seems to be more common in white (92% vs 88%, P = 0.01), male (77% vs 59%, P < 0.0001) patients.
The prevalence of AF has increased significantly over the past 50 years. Between 1968 and 1970, the prevalence of AF in US men aged 65–84 years was reported to be 3.2%, but this increased to 9.1% in the same age group between 1987 and 1989 . A similar increase in the prevalence of AF, from 0.84 to 1.49% in men, and from 0.83 to 1.29% in women, was also observed in the UK between 1994 and 2003 .
Prevalence of atrial fibrillation in France
A study carried out in the 1990s (ALFA) attempted to characterize the different subsets of AF observed by general cardiologists in office practice in France. The relative prevalences of paroxysmal, chronic and recent onset AF among 756 patients with electrocardiogram-confirmed AF were 22.1, 51.4 and 26.4%, respectively . Patients with chronic AF were significantly older ( P < 0.0002) than those with paroxysmal AF but there was no association between sex and type of AF . Asymptomatic AF was present in 11.4% of patients.
The current prevalence of AF in France was recently estimated by Guize et al. in a study population comprising 98,961 men and 55,109 women, who had a free check-up in the Centre d’Investigations Préventives et Cliniques, Paris . AF was identified in 0.05% of men and 0.01% of women aged < 50 years, compared with in 6.5% of men and 5.2% of women aged > 80 years.
By applying the prevalence figures calculated for the different age groups and sexes in the USA, Australia and Europe to the French population, we estimated that there are currently between 600,000 and 1 million people in France with AF, that two-thirds of these subjects are likely to be aged > 75 years and that most of them will be women.
Incidence of atrial fibrillation: international data
The incidence of AF is also higher in older subjects ( Table 2 ) . The incidence of AF has been reported to double for every 10-year increment in age, with an annual incidence of 3.1 cases per 1000 patient-examinations in men and 1.9 cases in women aged 55–64 years, increasing to 38.0 and 31.4 cases, respectively, in elderly patients aged 85–94 years . Mabo et al. also reported a higher annual incidence in older subjects, increasing from 0.1% in those aged < 40 years to more than 1.5% in women and more than 2% in men aged > 80 years .
| Framingham study | Cardiovascular Health study | Manitoba follow-up study | Rotterdam study | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Age (years) | Incidence of AF | Age (years) | Incidence of AF | Age (years) | Incidence of AF | Age (years) | Incidence of AF | |||
| Men | Women | Men | Women | Men & women | Men | Women | ||||
| < 50 | 0.5 | |||||||||
| 50–54 | 0.8 | |||||||||
| 55–64 | 3.1 | 1.9 | 55–59 | 2.2 | 55–59 | 2.6 | ||||
| 60–64 | 3.6 | 60–64 | 4.9 | 2.1 | ||||||
| 65–75 | 9.0 | 5.5 | 65–69 | 12.3 | 10.9 | 65–69 | 5.0 | 65–69 | 6.6 | 4.7 |
| 70–74 | 22.8 | 9.1 | ≥ 70 | 9.7 | 70–74 | 12.4 | 10.1 | |||
| 75–84 | 17.5 | 15.0 | 75–79 | 34.8 | 23.1 | 75–79 | 19.9 | 11.5 | ||
| ≥ 80 | 58.7 | 25.1 | 80–84 | 25.5 | 18.2 | |||||
| 85–94 | 38.0 | 31.4 | ≥ 85 | 16.9 | ≥ 85 | 25.4 | 15.2 | |||
| Total | Total | 26.4 | 14.1 | Total | 2.0 | Total | 11.5 | 8.9 | ||
| Combined total | 19.2 | |||||||||
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