Admissions with atrial fibrillation in a multiracial population in Kuala Lumpur, Malaysia
Introduction
Atrial fibrillation (AF) is the most common chronic cardiac arrhythmia [1]. The annual incidence per 1000 person years has been reported at 3.1 cases in men and 1.9 cases in women age 55–64 years, rising to 38.0 and 31.4 cases in men and women in the 85–94 age group [2]. Risk factors for AF include male sex, advancing age, ischaemic heart disease, hypertension, valvular heart disease, heart failure, and diabetes [2]. Atrial fibrillation is also an important risk factor for stroke, resulting in a 3- to 5-fold excess risk [3], [4]. Nevertheless, the information on epidemiology, risk factors, treatment and complications of AF are largely confined to studies in Western (Caucasian) populations.
Although there are recognised differences in cardiovascular disease and stroke between ethnic groups, epidemiological data on AF in non-white populations are very limited. Some racial differences in the prevalence of AF were suggested by the Cardiovascular Health Study, in which 5% of the study population were black [5], where the latter ethnic group had half the age-adjusted risk of developing AF compared with whites (RR 0.47, 95% C.I. 0.22–1.01). In the Northern Manhattan Stroke Study, of those patients presenting with ischaemic stroke, AF was more common in whites (29%) than in either black (11%) or hispanic (11%) patient groups [6]. In our previous survey of acute medical admissions with AF to a city centre hospital in Birmingham, UK, serving a multiethnic population, only 4% were black and 9% were of Indo-Asian origin [7]. The most common risk factor in Afro-Caribbean patients was hypertension, whereas Indo-Asian patients were more likely to have ischaemic heart disease and were younger than black or white patients. Our general practice-based survey in the west Birmingham AF project found the prevalence of AF to be only 0.6% amongst Indo-Asians, who as an ethnic group comprised 65% of the 25 051 general practice population surveyed [8]. Previous small studies have also estimated the prevalence of, and risk factors associated with AF in India, Africa, Japan, Thailand and Hong Kong [9], [10], [11], [12], [13].
AF is common amongst acute medical admissions, and in one USA series, AF accounted for 34.5% of patients admitted with a rhythm disturbance [14]. In view of the lack of information on AF in non-caucasian populations, the aim of the present survey was to study the prevalence of AF in the multiracial population of Malaysia, and to describe the clinical features and management of these patients.
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Patients and methods
We conducted a prospective survey of acute medical admissions to a busy city centre general hospital in Kuala Lumpur, Malaysia over a 4-week period (15th May 2000 to 13th June 2000). This hospital is the main government hospital serving a 1.4 million catchment population of the city of Kuala Lumpur. The multiracial population of Malaysia consists primarily of three main ethnic groups: Malays, Chinese, and Indians.
During the study period, acute admissions were screened for AF. Subjects were
Results
There were a total of 1435 adult acute medical admissions over the 4-week study period. Of these, 40 patients (2.8%; 21 male, mean age 65 years, S.D. 10.3, range 28–93 years) of these had AF: 12 (30%) patients were known to have chronic AF, seven patients (17.5%) had paroxysmal AF and 21 patients (52.5%) patients were newly diagnosed. Of the AF patients, 18 were Malay (44%), 16 were Chinese (40%) and six were Indian (16%).
Discussion
The worldwide literature on AF in non-white groups is limited. In the present study which was based in a busy city centre general hospital in Kuala Lumpur, Malaysia, we found an overall prevalence of AF amongst acute medical admissions of 2.8%, which is lower than reported in similarly conducted previous studies, looking at acute medical admissions in the UK [7], [15].
The prevalence of AF worldwide has been reported to be as high as 22% in one study on sick elderly inpatients, or as low as 0.1%
Acknowledgments
We thank the staff of Kuala Lumpur General Hospital for assistance in conducting our survey.
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