Cardioembolic Stroke Is the Most Serious Problem in the Aging Society: Japan Standard Stroke Registry Study Yuji Kato, MD, PhD,* Takeshi Hayashi, MD, PhD,* Norio Tanahashi, MD, PhD,* Shotai Kobayashi, MD, PhD,† and the Japan Standard Stroke Registry Study Group
Background: Japan has the fastest aging society in the world. Older patients have a different stroke risk profile and different stroke features compared with younger patients. The aim of the present study was to examine the stroke subtypes, risk factor profiles, stroke severities, and functional outcomes in the different age groups. Methods: A total of 78,096 patients with acute ischemic stroke, including transient ischemic attacks, were included in a multicenter, hospital-based registration study based on a computerized database involving 95 Japanese institutes between 2000 and 2012. Results: The frequency of atrial fibrillation increased even after the age of 90 years; consequently, the proportion of patients experiencing cardioembolic stroke also increased in the same age group. Furthermore, more severe symptoms on arrival and worse functional outcomes were observed with increasing age. The frequency of hypertension increased with age, peaking in patients in their 70s, and decreasing slightly thereafter. The frequency of diabetes mellitus and hyperlipidemia peaked in patients in their 50s or 60s and gradually decreased thereafter. Conclusion: The findings of the present study suggest that in the currently aging society, cardioembolic stroke is the most important stroke subtype. The roles of hypertension, diabetes mellitus, and hyperlipidemia are greatest in stroke patients in their 50s to 60s. In older patients, the role of atrial fibrillation is more significant. Key Words: Age stratification—ischemic stroke—epidemiology— Japanese. Ó 2014 by National Stroke Association
Introduction The stroke mortality is higher, and coronary heart disease mortality is lower in Japanese populations compared with Western populations,1 even though the incidence and mortality of stroke, particularly intracerebral hemor-
From the *Department of Neurology and Cerebrovascular Medicine, Saitama International Medical Center, Saitama Medical University, Saitama; and †Department of Neurology, Shimane University, Shimane, Japan. Received November 14, 2014; accepted November 19, 2014. Address correspondence to Yuji Kato, MD, PhD, Department of Neurology and Cerebrovascular Medicine, Saitama International Medical Center, 1397-1 Yamane, Hidaka, Saitama 350-1298, Japan. E-mail: [email protected]. 1052-3057/$ - see front matter Ó 2014 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2014.11.019
rhage, have markedly decreased from the 1960s to the 1970s.1-3 This may be attributed to the reduction in blood pressure levels and the improvement of a lower nutrition status. Consequently, stroke has retracted to being the fourth leading cause of death. However, the prevalence of stroke has been increasing and is still the most frequent cause of a bedridden state. Japan is the fastest aging society in the world and, as a result, is facing a rapid increase in its disabled population and in associated health care costs. Older age groups have different stroke risk profiles and different stroke features compared with younger age groups.4 Nevertheless, there are few studies on stroke, comparing different age groups.5-9 The aim of the present study was to examine stroke subtypes, risk factor profiles, stroke severities, and functional outcomes in different age groups using the Japan Standard Stroke Registry Study database.10-13
Journal of Stroke and Cerebrovascular Diseases, Vol. -, No. - (---), 2015: pp 1-4
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Figure 1. Sex and age distribution. Men were more commonly septuagenarians or younger, and women were more common octogenarians or older.
Methods Japan Standard Stroke Registry Study is an ongoing multicenter stroke registration study based on a computerized database involving 95 Japanese institutes. From January 2000 to December 2012, 101,164 patients with acute stroke were registered. Among them, 78,096 patients with ischemic stroke were enrolled in the present study. Stroke subtypes were defined according to the National Institute for Neurological Disorders and Stroke Classification of Cerebrovascular Disease III system: atherothrombotic, cardioembolic, lacuna, and stroke of other etiologies.14 Underlying risk factors, such as hypertension, diabetes mellitus, hyperlipidemia, and atrial fibrillation, were assessed. The National Institutes of Health Stroke Scale (NIHSS) was used on admission to evaluate stroke severity. A modified Rankin Scale score was used at hospital discharge to assess stroke outcomes.
Results Among the 78,096 enrolled patients, there were 72,775 cases of cerebral infarction and 5321 cases of transient ischemic attacks (TIAs), all of which were included in the analysis. Of the enrolled patients, 47,465 were men
and 30,631 were women. The sex and age distributions of patients registered in the study are shown in Figure 1. Women were older than men at stroke onset (75.5 6 12.1 and 69.7 6 11.6 years, respectively). Regarding ischemic stroke subtype, the absolute distribution is shown in Figure 2, A, whereas the relative distribution, excluding TIAs and stroke of other etiologies, is shown in Figure 2, B. The absolute numbers of cardioembolic stroke increased in the 80- to 84-year-old age group. The proportion of cardioembolic strokes increased consistently, with age, among patients in their 50s to those older than 90 years. In patients older than 80 years, cardioembolic stroke was the most common stroke subtype. The absolute numbers of lacunar and atherothrombotic infarctions increased with age and reached their peaks among patients 70- to 74-year old and 75-to 80-year old, respectively. The frequencies of hypertension, diabetes mellitus, hyperlipidemia, and atrial fibrillation in the different age groups are shown in Figure 3. The frequency of hypertension increased, with age, up to the 70s, but decreased slightly thereafter (Fig 3, A). The frequency of diabetes mellitus was 19% in the under 50 years age group, reached its peak in patients in their 60s, and gradually decreased thereafter (Fig 3, B). The frequency of hyperlipidemia reached its peak in patients in their 50s and gradually decreased thereafter (Fig 3, C). The frequency of atrial fibrillation increased with age (Fig 3, D). The initial NIHSS scores are shown in Figure 4. The initial NIHSS score was higher in the older age groups. The plots in Figure 5 represent the distribution of modified Rankin Scale grades in the different age groups. Functional outcomes declined with increasing age.
Discussion This was a nationwide multicenter registration study on how age affects the characteristics and functional outcomes of Japanese patients with acute ischemic stroke, including TIA. In the present study, the rate of cardioembolic stroke increased with age, and the older groups were more likely to have severe symptoms on arrival and poorer outcomes.
Figure 2. (A) Absolute distribution of stroke subtypes by age group. The number of patients with cardioembolic stroke reached its peak among the 80- to 84-year-old patients. In patients older than 80 years, cardioembolism was the most common stroke subtype. (B) Relative distribution of stroke subtypes, by age group, excluding transient ischemic attacks and strokes of undefined etiologies. The proportion of cardioembolic stroke increased consistently as patients increased in age from 50 to older than 90 years. Abbreviation: TIA, transient ischemic attack.
ISCHEMIC STROKE IN DIFFERENT AGE GROUPS IN JAPAN
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Figure 3. The frequencies of various risk factors by age group. The frequency of hypertension increased with age up to the 70s but slightly decreased thereafter. The frequencies of diabetes mellitus and hyperlipidemia reached their peaks in patients in their 50s or 60s and gradually decreased thereafter. The frequency of atrial fibrillation increased with age.
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Background: Japan has the fastest aging society in the world. Older patients have a different stroke risk profile and different stroke features compared with younger patients. The aim of the present study was to examine the stroke subtypes, risk factor profiles, stroke severities, and functional outcomes in the different age groups. Methods: A total of 78,096 patients with acute ischemic stroke, including transient ischemic attacks, were included in a multicenter, hospital-based registration study based on a computerized database involving 95 Japanese institutes between 2000 and 2012. Results: The frequency of atrial fibrillation increased even after the age of 90 years; consequently, the proportion of patients experiencing cardioembolic stroke also increased in the same age group. Furthermore, more severe symptoms on arrival and worse functional outcomes were observed with increasing age. The frequency of hypertension increased with age, peaking in patients in their 70s, and decreasing slightly thereafter. The frequency of diabetes mellitus and hyperlipidemia peaked in patients in their 50s or 60s and gradually decreased thereafter. Conclusion: The findings of the present study suggest that in the currently aging society, cardioembolic stroke is the most important stroke subtype. The roles of hypertension, diabetes mellitus, and hyperlipidemia are greatest in stroke patients in their 50s to 60s. In older patients, the role of atrial fibrillation is more significant. Key Words: Age stratification—ischemic stroke—epidemiology— Japanese. Ó 2014 by National Stroke Association
Introduction The stroke mortality is higher, and coronary heart disease mortality is lower in Japanese populations compared with Western populations,1 even though the incidence and mortality of stroke, particularly intracerebral hemor-
From the *Department of Neurology and Cerebrovascular Medicine, Saitama International Medical Center, Saitama Medical University, Saitama; and †Department of Neurology, Shimane University, Shimane, Japan. Received November 14, 2014; accepted November 19, 2014. Address correspondence to Yuji Kato, MD, PhD, Department of Neurology and Cerebrovascular Medicine, Saitama International Medical Center, 1397-1 Yamane, Hidaka, Saitama 350-1298, Japan. E-mail: [email protected]. 1052-3057/$ - see front matter Ó 2014 by National Stroke Association http://dx.doi.org/10.1016/j.jstrokecerebrovasdis.2014.11.019
rhage, have markedly decreased from the 1960s to the 1970s.1-3 This may be attributed to the reduction in blood pressure levels and the improvement of a lower nutrition status. Consequently, stroke has retracted to being the fourth leading cause of death. However, the prevalence of stroke has been increasing and is still the most frequent cause of a bedridden state. Japan is the fastest aging society in the world and, as a result, is facing a rapid increase in its disabled population and in associated health care costs. Older age groups have different stroke risk profiles and different stroke features compared with younger age groups.4 Nevertheless, there are few studies on stroke, comparing different age groups.5-9 The aim of the present study was to examine stroke subtypes, risk factor profiles, stroke severities, and functional outcomes in different age groups using the Japan Standard Stroke Registry Study database.10-13
Journal of Stroke and Cerebrovascular Diseases, Vol. -, No. - (---), 2015: pp 1-4
1
Y. KATO ET AL.
2
Figure 1. Sex and age distribution. Men were more commonly septuagenarians or younger, and women were more common octogenarians or older.
Methods Japan Standard Stroke Registry Study is an ongoing multicenter stroke registration study based on a computerized database involving 95 Japanese institutes. From January 2000 to December 2012, 101,164 patients with acute stroke were registered. Among them, 78,096 patients with ischemic stroke were enrolled in the present study. Stroke subtypes were defined according to the National Institute for Neurological Disorders and Stroke Classification of Cerebrovascular Disease III system: atherothrombotic, cardioembolic, lacuna, and stroke of other etiologies.14 Underlying risk factors, such as hypertension, diabetes mellitus, hyperlipidemia, and atrial fibrillation, were assessed. The National Institutes of Health Stroke Scale (NIHSS) was used on admission to evaluate stroke severity. A modified Rankin Scale score was used at hospital discharge to assess stroke outcomes.
Results Among the 78,096 enrolled patients, there were 72,775 cases of cerebral infarction and 5321 cases of transient ischemic attacks (TIAs), all of which were included in the analysis. Of the enrolled patients, 47,465 were men
and 30,631 were women. The sex and age distributions of patients registered in the study are shown in Figure 1. Women were older than men at stroke onset (75.5 6 12.1 and 69.7 6 11.6 years, respectively). Regarding ischemic stroke subtype, the absolute distribution is shown in Figure 2, A, whereas the relative distribution, excluding TIAs and stroke of other etiologies, is shown in Figure 2, B. The absolute numbers of cardioembolic stroke increased in the 80- to 84-year-old age group. The proportion of cardioembolic strokes increased consistently, with age, among patients in their 50s to those older than 90 years. In patients older than 80 years, cardioembolic stroke was the most common stroke subtype. The absolute numbers of lacunar and atherothrombotic infarctions increased with age and reached their peaks among patients 70- to 74-year old and 75-to 80-year old, respectively. The frequencies of hypertension, diabetes mellitus, hyperlipidemia, and atrial fibrillation in the different age groups are shown in Figure 3. The frequency of hypertension increased, with age, up to the 70s, but decreased slightly thereafter (Fig 3, A). The frequency of diabetes mellitus was 19% in the under 50 years age group, reached its peak in patients in their 60s, and gradually decreased thereafter (Fig 3, B). The frequency of hyperlipidemia reached its peak in patients in their 50s and gradually decreased thereafter (Fig 3, C). The frequency of atrial fibrillation increased with age (Fig 3, D). The initial NIHSS scores are shown in Figure 4. The initial NIHSS score was higher in the older age groups. The plots in Figure 5 represent the distribution of modified Rankin Scale grades in the different age groups. Functional outcomes declined with increasing age.
Discussion This was a nationwide multicenter registration study on how age affects the characteristics and functional outcomes of Japanese patients with acute ischemic stroke, including TIA. In the present study, the rate of cardioembolic stroke increased with age, and the older groups were more likely to have severe symptoms on arrival and poorer outcomes.
Figure 2. (A) Absolute distribution of stroke subtypes by age group. The number of patients with cardioembolic stroke reached its peak among the 80- to 84-year-old patients. In patients older than 80 years, cardioembolism was the most common stroke subtype. (B) Relative distribution of stroke subtypes, by age group, excluding transient ischemic attacks and strokes of undefined etiologies. The proportion of cardioembolic stroke increased consistently as patients increased in age from 50 to older than 90 years. Abbreviation: TIA, transient ischemic attack.
ISCHEMIC STROKE IN DIFFERENT AGE GROUPS IN JAPAN
A
Figure 3. The frequencies of various risk factors by age group. The frequency of hypertension increased with age up to the 70s but slightly decreased thereafter. The frequencies of diabetes mellitus and hyperlipidemia reached their peaks in patients in their 50s or 60s and gradually decreased thereafter. The frequency of atrial fibrillation increased with age.
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