Original articleIncidence of chronic atrial fibrillation in general practice and its treatment pattern
Section snippets
Background
Atrial Fibrillation (AF) is the most common chronic arrhythmia, occurring most frequently in the presence of other cardiovascular disease [1], and is now recognized as the most common cardiac disorder leading to systemic emboli [2].
AF incidence and prevalence is known to increase steeply with advancing age. Incidence at age 50 varies between 0.4 and 0.7 per 1,000 person-years, while at the age of 80 it lies between 1 and 2%. The corresponding prevalence goes from 1.1 per 1,000 patients at age
Source population
We performed a retrospective cohort study using data from the General Practice Research Database (GPRD). The source population includes approximately three million residents in the UK registered with general practitioners (GPs), which provide data to the GPRD. The information recorded includes demographics, medical diagnoses, referrals to consultant and hospital, and a register of written prescriptions. In addition, the GP may record laboratory results and other medical data in a free text
Results
The incidence rate of chronic AF was estimated to be 1.7 per 1,000 person-years. The incidence increased markedly with age. We found a rate of 0.05 among patients aged 40 to 49 years, while among patients aged 80–89 this was 8.6 (Fig. 1). Women presented a lower incidence rate than men, specially in young age. The overall age-adjusted relative risk among males was 1.4 (95%CI 1.2–1.6).
Table 1 shows the distribution of health-related characteristics in both cases and controls. Age was the major
Discussion
We observed an overall incidence rate of chronic AF of approximately 3 per 1,000 person-years among patients older than 60 years in the UK, an estimate lower than that reported by other authors in the United States 4, 15. Different methods of case identification and varying operational definitions of AF make comparisons between studies difficult. In the Cardiovascular Heart Study [4], the majority of incident AF patients were identified in the hospital, with only 7% whose AF was still present
Acknowledgements
We thank the staff at EPIC and the participating general practitioners for their collaboration. We also thank the Boston Collaborative Drug Surveillance Program (BCDSP) for providing access to the database. This study was supported by a research grant of AstraZeneca.
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