- Email: [email protected]
Risk Factors among Stroke Subtypes in Brazil
Risk Factors among Stroke Subtypes in Brazil Luiz Carlos Porcello Marrone, MD,* Luciano Passamani Diogo, MD, PhD,† Faberson Mocelin de Oliveira, MD,‡ Sheila Trentin, MD,x Renata Siciliani Scalco,x Andrea Garcia de Almeida, MD,* Luis del Carmo Vega Gutierres, MD,* ^nio Carlos Huf Marrone, MD, PhD,{ and Jaderson Costa da Costa, MD, PhDk Anto
Stroke is a leading cause of mortality and disability in Brazil. Among the risk factors for cerebrovascular disease, some have more influence than others in certain stroke subtypes. Little data are available in the literature on the prevalence of stroke subtypes in Latin America. We analyzed data from 688 patients with acute ischemic stroke (52.3% women; mean age, 65.7 years) who were enrolled in a stroke data bank. Standardized data assessment and stroke subtype classification were used. The most common stroke subtype was large-artery atherosclerosis (n 5 223; 32.4%), followed by cardioembolism (n 5 195; 28.3%), and microangiopathy (n 5 127; 18.5%). Stroke risk factors differ among stroke subtypes. The population of South America is ethnically diverse, and few previous studies have describe the distribution of risk factors among stroke subtypes in this population. In this study, the most important risk factors were hypertension and dyslipidemia. Key Words: Stroke in Brazil—Trial of Org 10172 in Acute Stroke Treatment classification— stroke risk factors. Ó 2013 by National Stroke Association
Stroke is a leading cause of mortality and disability in Brazil and in Latin America overall because of an increasing life expectancy and changes in the lifestyle of the population. Current knowledge of stroke risk factors is based mostly on North American and European studies, however.1 Stroke is classified primarily into 2 types, ischemic (80%-85% of cases) and hemorrhagic (15%-20% of cases). From the *Neurology Department, Sao Lucas Hospital, Pontifıciae Universidade Cat olica do Rio Grande do Sul (PUCRS)/ Instituto do Cerebro (INSCER); †Department of Internal Medicine, PUCRS School of Medicine; ‡PUCRS School of Medicine; xNeurology Department, Sao Lucas Hospital, Pontifıciae Universidade Cat olica do Rio Grande do Sul (PUCRS); {Neurology Department, PUCRS School of Medicine/Brain Institute; and kNeurology Department, PUCRS School of Medicine, Pontifıciae Universidade Cat olica do Rio Grande do Sul (PUCRS). Received January 31, 2011; revision received May 20, 2011; accepted May 21, 2011. Address correspondence to Luiz Carlos Porcello Marrone, MD, Neurology Department, Sao Lucas Hospital, Rua Coronel Bordini 300/1204, 90440-002 Porto Alegre, RS, Brazil. E-mail: lcpmarrone@ gmail.com. 1052-3057/$ - see front matter Ó 2013 by National Stroke Association doi:10.1016/j.jstrokecerebrovasdis.2011.05.022
32
The clinical characteristics of stroke vary according to etiology and risk factors, which may be related to racial and sociocultural factors.2-4 The Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification system designates 5 subtypes of ischemic stroke: large-artery atherosclerosis, cardioembolism, small-vessel occlusion, stroke of other determined etiology, and stroke of undetermined etiology. The identification of stroke etiology guides decisions regarding early and long-term secondary prevention in current practice. Differences in these factors could influence the response to acute stroke therapy and overall stroke outcome. The etiology of ischemic stroke affects prognosis, outcome, and management.5 The most important etiologies of ischemic stroke include large-artery atherosclerosis (macroangiopathy), cardioembolism, and cerebral small-vessel disease (microangiopathy).2,6-11 The prevalence of risk factors in patients with stroke varies by subtype and the population studied.5,12-15 For example, a study of ischemic stroke in persons with diabetes revealed a different clinical pattern from that seen in persons without diabetes, with a greater prevalence of atherothrombotic stroke and lacunar infarcts.13
Journal of Stroke and Cerebrovascular Diseases, Vol. 22, No. 1 (January), 2013: pp 32-35
STROKE SUBTYPES IN BRAZIL
33
The objectives of the present study were to describe the prevalence of stroke risk factors in Porto Alegre, Brazil and to determine the patterns of stroke subtypes in a population of patients in S~ao Lucas Hospital.
Materials and Methods We analyzed data from 688 patients with acute ischemic stroke admitted to S~ao Lucas Hospital between January 2006 and December 2009. We analyzed the prevalence of the most important stroke risk factors in each stroke subtype, including age (over or under 65 years), sex, diabetes, hypertension, smoking, dyslipidemia, previous stroke, cardiac dysrhythmias, and family history of coronary disease. Porto Alegre is a city in southern Brazil with a population of 1.4 million inhabitants, predominantly of European and African origin. Our study was carried out exclusively with patients admitted in the hospital’s emergency department. In this investigation, all patients underwent brain computed tomography and/or magnetic resonance imaging (both in 85.6% of the patients), electrocardiography, chest radiography, and basic blood tests. The majority of patients also underwent transesophageal echocardiography, Doppler ultrasonography of the neck vessels, and/ or angiomagnetic resonance imaging. Ischemic strokes were classified into the following categories according to TOAST classification.5 Hypertension was defined as receipt of antihypertensive therapy or 2 measurements of systolic pressure .140 mm Hg and/or diastolic pressure .90 mm Hg. Diabetes mellitus was defined as a history of elevated serum glucose level (.126 mg/dL) on 2 independent readings before stroke or receipt of antidiabetes medication. Dyslipidemia was defined as a history of total cholesterol .200 mg/dL or triglycerides .200 mg/dL or receipt of lipid-lowering medication. Patients who presented in the emergency department with previous stroke (without acute lesions or who had been treated as an outpatient were not included in the sample. The stroke subtype was identified after review all imaging data.
Continuous variables are presented as mean 6 standard deviation, age were compared by analysis of variance with Tukey’s post hoc test according to TOAST subtypes. Categorical variables are presented as percentages, and they were compared among the subtypes using Pearson’s c2 test with 5 degrees of freedom. Thus, significance levels refer to differences among all groups. All statistical analyses were performed using SPSS version 13.0 (SPSS Inc, Chicago, IL).
Results Our study cohort comprised included 688 patients with ischemic stroke, including 360 (52.3%) women and 328 (47.7%) men, with a mean age of 65.7 6 11.26 years. Large-artery atherosclerosis was the most common stroke subtype (n 5 223; 32.4%), followed by cardioembolism (n 5 195; 28.3%), microangiopathy (n 5 127; 18.5%), unknown (n 5 113; 16.4%), and other etiology (n 5 30; 4.4%). The mean age of the patients in the macroangiopathy, microangiopathy, and cardioembolic groups was .65 years, compared with 48 years in the unknown and other etiology groups. We speculated that approximately 15% of our patients had intracranial atherosclerotic disease. In our cohort, the prevalence of hypertension was 75.1% (n 5 517), that of diabetes was 22.6% (n 5 146), that of dyslipidemia was 47.1% (n 5 324), and that of smoking (current or previous) was 23.8% (n 5 164). These prevalences varied among the subtypes of stroke when evaluated separately (Table 1). For example, hypertension and smoking were most prevalent in the microangiopathy group, whereas dyslipidemia and diabetes were more common in the macroangiopathy group. Hypertension was the major risk factor in all groups. Atrial fibrillation was present in 47.7% of the patients in the cardioembolism group. The prevalence of previous ischemic event was 26.8% in the cardioembolism group, 24.7% in the atherothrombosis of large vessels group, and 20.9% in the microangiopathy group. Overall, 127 patients (18.4%) had a family history of coronary disease, and 113 had a family history of cerebrovascular disease.
Table 1. Risk factors among stroke subtypes, %
TOAST, n Males, % Females, % Age .65 years, % Hypertension, % Diabetes, % Dyslipidemia, % Smoking, %*
Macroangiopathy
Cardioembolism
Microangiopathy
Other etiologies
Unknown
223 47.5 52.3 63.2 80.7 26.9 57.8 29.1
195 46.7 53.3 56.9 69.7 18.5 40 16.9
127 50.4 49.6 72.4 92.1 27.6 50.4 29.1
30 26.7 73.3 13.3 43.3 10 23.3 13.3
113 52.2 47.8 54.9 62.8 10.2 40.7 22.1
*Includes patients who were smokers and stopped smoking cigarettes within the previous 5 years.
P
.153 ,.001 ,.001 ,.01 ,.03 .014
L.C. PORCELLO MARRONE ET AL.
34
Table 2. Stroke subtypes in South American, studies % Study location
n
Porto Alegre Guayaquil2 Santiago6 Buenos Aires7 Bogota8 Santiago9
688 313 233 250 119 110
Macroangiopathy Cardioembolism Small-vessel occlusion Other etiology Undetermined etiology 32.4 7.4 33.5 12 19 7
28.3 14 32.6 21 18 14
Discussion Our study was conducted exclusively with patients who were admitted to the emergency department with signs of acute stroke, which possibly confers a more serious character to the group selected for study. A previous study that assessed differences in risk factors between hospitalized patients and nonhospitalized patients found no differences between the 2 groups in terms of the subtype of ischemia and the prevalence of risk factors.16 The hospitalized patients had a higher prevalence of cardioembolic phenomena of ischemia and a lower prevalence of microangiopathy.16 In an evaluation of 5017 patients with stroke in Germany, the most common subtype was cardioembolic (25.6%), followed by unknown etiology (22.7%), macroangiopathy (20.9%), microangiopathy (20.5%), concurrent etiologies (6.9%), and other causes (3.5%).10 In a French study that analyzed 332 patients with ischemic stroke, the distribution of ischemic stroke subtypes was 119 (35.8%) large-artery atherosclerosis, 89 (26.8%) small artery occlusion, 81 (24.4%) cardioembolism, and 43 (13%) other and undetermined causes.11 Overall, the most frequent vascular risk factor was hypertension, with a total prevalence of 62%. In Spain, Moreno et al15 studied 615 patients (307 controls) and found that hypertension was the most prevalent risk factor in all stroke subgroups, followed by smoking (which is more closely associated with atherothrombotic types) and other unspecified causes. When analyzed separately by sex, men had a higher prevalence of smoking and dyslipidemia than women, whereas women had more hypertension than men, and diabetes had a similar prevalence in men and women. In that study, the atherothrombotic subtype was the most prevalent (32.5%), followed by indefinite (29.2%), cardioembolic (18.5%), lacunar (16.6%), and other etiologies (3.2%).15 Sacco et al17 reported racial-ethic–based differences in age in their cohort, with whites having an older age at stroke compared with blacks and Hispanics. Differences in other risk factors are also reported among these groups.17 The South American population is heterogeneous and includes native Indians, immigrants of all races, and a number of racial admixtures. Porto Alegre in southern
18.5 43.1 14.1 42 19 43
4.4 6 5.2 6 8 6
16.4 29.5 14.6 18 21 29
Brazil has a population of approximately 1.4 million, composed of immigrants of various ethnic origins. Studies of stroke incidence in South America have yielded rates ranging from 0.35 to 1.83 per 1000 population.18-20 However, in some regions of Brazil, stroke is the leading cause of death and disability. Although stroke is the leading cause of death in South America, little data are available on the epidemiology of stroke subtypes. The most important South American studies are listed in Table 2. In summary, we found differences in the prevalence of major risk factors among the stroke subtypes, demonstrating that knowledge of pathophysiology is essential for the proper management of these patients. Given this, learning more about the epidemiologic data of the region is vital. In this study, the most prevalent risk factors were hypertension and dyslipidemia, and the most common etiology was large-artery atherosclerosis. The differences between our findings and those of previous studies may be attributed to variations in the patients samples in terms of age, sex, race, and socioeconomic conditions, and whether or not the patients were admitted to the emergency department.
References 1. Saposnik G, Del Brutto OH. Stroke in South America: A systematic review of incidence, prevalence, and stroke subtypes. Stroke 2003;34:2103-2107. 2. Del Brutto OH, Mosquera A, S anchez X, et al. Stroke subtypes among Hispanics living in Guayaquil, Ecuador: Results from the Luis Vernaza Hospital stroke registry. Stroke 1993;24:1833-1836. 3. Hassaballa H, Gorelick PB, West CP, et al. Racial differences in the trial of danaparoid in acute stroke (TOAST). Neurology 2001;57:691-697. 4. Bonita R. Epidemiology of stroke. Lancet 1992;339:342-344. 5. Adams HP, Bendixen BH, Kappelle LJ, et al. Classification of subtype of acute ischemic stroke: Definitions for use in a multicenter clinical trial. Stroke 1993;24:35-41. ~ ez L, Arriagada C, et al. 6. Nogales-Gaete J, N un Caracterizaci on clınica de 450 pacientes con enfermedad cerebrovascular ingresados a un hospital p ublico durante 1997. Rev Med Chil 2000;128:1227-1236. 7. Saposnik G, Caplan LR, Gonzalez LA, et al. Differences in stroke subtypes among natives and caucasians in Boston and Buenos Aires. Stroke 2000;31:2385-2389. 8. Pe~ na I, Ruiz C, Morillo LE, et al. Clasificaci on del TOAST en la pr actica clınica de un hospital universitario. Acta Neurol Colomb 2001;17:304-308.
STROKE SUBTYPES IN BRAZIL 9. Diaz V, Plate L, Erazo S, et al. Prevalencia de la ateromatosis carotıdea en pacientes con enfermedad cerebrovascular oclusiva. Rev Med Chil 2001;129:161-165. 10. Grau A, Weimar C, Buggle F, et al. Risk factors, outcome, and treatment in subtypes of ischemic stroke: The German Stroke Data Bank. Stroke 2001;32: 2559-2566. 11. Giroud Rouaud M, Osseby G-V, Durier J, et al. Ischemic stroke subtypes and associated risk factors: A French population-based study. J Neurol Neurosurg 2008; 12:1344-1348. 12. Biller J, Love BB. Vascular disease of nervous system. In: Bradley WG, Daroff RB, Fenichel GM, et al, eds. Neurology in Clinical Practice. Philadelphia: Butterworth Heinemann, 2004:1197-1249. 13. Arboix A, Rivas A, Garcia-Eroles L, et al. Cerebral infarction in diabetes: Clinical pattern, stroke subtypes, and predictors of in-hospital mortality. BMC Neurol 2005;5:9. 14. Jackson C, Sudlow C. Are lacunar strokes really different? A systematic review of differences in risk factor
35
15.
16.
17.
18.
19.
20.
profiles between lacunar and nonlacunar infarcts. Stroke 2005;36:891-904. Moreno VP, Garcia-Raso A, Garcia-Bueno MJ, et al. Factores de riesgo vascular en pacientes com ictus isquemico: Distribuci on seg un edad, sexo y subtipo de ictus. Ver Neurol 2008;46:593-598. Schulz UGR, Rothwell PM. Differences in vascular risk factors between etiological subtypes of ischemic stroke. Stroke 2003;34:2050-2059. Sacco RL, Kargman DE, Zamanillo MC. Racial-ethnic differences in stroke risk factors among hospitalized patients with cerebral infarction. Neurology 1995;45:659-663. Jaillard AS, Hommel M, Mazetti. Prevalence of stroke at high altitude (3380 m) in Cuzco, a town in Peru: A population-based study. Stroke 1995;26:562-568. Uribe CS, Jimenez I, Mora MO, et al. Epidemiologıa de las enfermedades cerebrovasculares en Sabaneta, Colombia (1992–1993). Rev Neurol 1997;25:1008-1012. Pradilla G, Pardo CA, Daza JS, et al. Neuroepidemiologıa en Colombia: Estudios en 16,032 individuos. Acta Neurol Colombiana 1995;11:129-133.
Stroke is a leading cause of mortality and disability in Brazil. Among the risk factors for cerebrovascular disease, some have more influence than others in certain stroke subtypes. Little data are available in the literature on the prevalence of stroke subtypes in Latin America. We analyzed data from 688 patients with acute ischemic stroke (52.3% women; mean age, 65.7 years) who were enrolled in a stroke data bank. Standardized data assessment and stroke subtype classification were used. The most common stroke subtype was large-artery atherosclerosis (n 5 223; 32.4%), followed by cardioembolism (n 5 195; 28.3%), and microangiopathy (n 5 127; 18.5%). Stroke risk factors differ among stroke subtypes. The population of South America is ethnically diverse, and few previous studies have describe the distribution of risk factors among stroke subtypes in this population. In this study, the most important risk factors were hypertension and dyslipidemia. Key Words: Stroke in Brazil—Trial of Org 10172 in Acute Stroke Treatment classification— stroke risk factors. Ó 2013 by National Stroke Association
Stroke is a leading cause of mortality and disability in Brazil and in Latin America overall because of an increasing life expectancy and changes in the lifestyle of the population. Current knowledge of stroke risk factors is based mostly on North American and European studies, however.1 Stroke is classified primarily into 2 types, ischemic (80%-85% of cases) and hemorrhagic (15%-20% of cases). From the *Neurology Department, Sao Lucas Hospital, Pontifıciae Universidade Cat olica do Rio Grande do Sul (PUCRS)/ Instituto do Cerebro (INSCER); †Department of Internal Medicine, PUCRS School of Medicine; ‡PUCRS School of Medicine; xNeurology Department, Sao Lucas Hospital, Pontifıciae Universidade Cat olica do Rio Grande do Sul (PUCRS); {Neurology Department, PUCRS School of Medicine/Brain Institute; and kNeurology Department, PUCRS School of Medicine, Pontifıciae Universidade Cat olica do Rio Grande do Sul (PUCRS). Received January 31, 2011; revision received May 20, 2011; accepted May 21, 2011. Address correspondence to Luiz Carlos Porcello Marrone, MD, Neurology Department, Sao Lucas Hospital, Rua Coronel Bordini 300/1204, 90440-002 Porto Alegre, RS, Brazil. E-mail: lcpmarrone@ gmail.com. 1052-3057/$ - see front matter Ó 2013 by National Stroke Association doi:10.1016/j.jstrokecerebrovasdis.2011.05.022
32
The clinical characteristics of stroke vary according to etiology and risk factors, which may be related to racial and sociocultural factors.2-4 The Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification system designates 5 subtypes of ischemic stroke: large-artery atherosclerosis, cardioembolism, small-vessel occlusion, stroke of other determined etiology, and stroke of undetermined etiology. The identification of stroke etiology guides decisions regarding early and long-term secondary prevention in current practice. Differences in these factors could influence the response to acute stroke therapy and overall stroke outcome. The etiology of ischemic stroke affects prognosis, outcome, and management.5 The most important etiologies of ischemic stroke include large-artery atherosclerosis (macroangiopathy), cardioembolism, and cerebral small-vessel disease (microangiopathy).2,6-11 The prevalence of risk factors in patients with stroke varies by subtype and the population studied.5,12-15 For example, a study of ischemic stroke in persons with diabetes revealed a different clinical pattern from that seen in persons without diabetes, with a greater prevalence of atherothrombotic stroke and lacunar infarcts.13
Journal of Stroke and Cerebrovascular Diseases, Vol. 22, No. 1 (January), 2013: pp 32-35
STROKE SUBTYPES IN BRAZIL
33
The objectives of the present study were to describe the prevalence of stroke risk factors in Porto Alegre, Brazil and to determine the patterns of stroke subtypes in a population of patients in S~ao Lucas Hospital.
Materials and Methods We analyzed data from 688 patients with acute ischemic stroke admitted to S~ao Lucas Hospital between January 2006 and December 2009. We analyzed the prevalence of the most important stroke risk factors in each stroke subtype, including age (over or under 65 years), sex, diabetes, hypertension, smoking, dyslipidemia, previous stroke, cardiac dysrhythmias, and family history of coronary disease. Porto Alegre is a city in southern Brazil with a population of 1.4 million inhabitants, predominantly of European and African origin. Our study was carried out exclusively with patients admitted in the hospital’s emergency department. In this investigation, all patients underwent brain computed tomography and/or magnetic resonance imaging (both in 85.6% of the patients), electrocardiography, chest radiography, and basic blood tests. The majority of patients also underwent transesophageal echocardiography, Doppler ultrasonography of the neck vessels, and/ or angiomagnetic resonance imaging. Ischemic strokes were classified into the following categories according to TOAST classification.5 Hypertension was defined as receipt of antihypertensive therapy or 2 measurements of systolic pressure .140 mm Hg and/or diastolic pressure .90 mm Hg. Diabetes mellitus was defined as a history of elevated serum glucose level (.126 mg/dL) on 2 independent readings before stroke or receipt of antidiabetes medication. Dyslipidemia was defined as a history of total cholesterol .200 mg/dL or triglycerides .200 mg/dL or receipt of lipid-lowering medication. Patients who presented in the emergency department with previous stroke (without acute lesions or who had been treated as an outpatient were not included in the sample. The stroke subtype was identified after review all imaging data.
Continuous variables are presented as mean 6 standard deviation, age were compared by analysis of variance with Tukey’s post hoc test according to TOAST subtypes. Categorical variables are presented as percentages, and they were compared among the subtypes using Pearson’s c2 test with 5 degrees of freedom. Thus, significance levels refer to differences among all groups. All statistical analyses were performed using SPSS version 13.0 (SPSS Inc, Chicago, IL).
Results Our study cohort comprised included 688 patients with ischemic stroke, including 360 (52.3%) women and 328 (47.7%) men, with a mean age of 65.7 6 11.26 years. Large-artery atherosclerosis was the most common stroke subtype (n 5 223; 32.4%), followed by cardioembolism (n 5 195; 28.3%), microangiopathy (n 5 127; 18.5%), unknown (n 5 113; 16.4%), and other etiology (n 5 30; 4.4%). The mean age of the patients in the macroangiopathy, microangiopathy, and cardioembolic groups was .65 years, compared with 48 years in the unknown and other etiology groups. We speculated that approximately 15% of our patients had intracranial atherosclerotic disease. In our cohort, the prevalence of hypertension was 75.1% (n 5 517), that of diabetes was 22.6% (n 5 146), that of dyslipidemia was 47.1% (n 5 324), and that of smoking (current or previous) was 23.8% (n 5 164). These prevalences varied among the subtypes of stroke when evaluated separately (Table 1). For example, hypertension and smoking were most prevalent in the microangiopathy group, whereas dyslipidemia and diabetes were more common in the macroangiopathy group. Hypertension was the major risk factor in all groups. Atrial fibrillation was present in 47.7% of the patients in the cardioembolism group. The prevalence of previous ischemic event was 26.8% in the cardioembolism group, 24.7% in the atherothrombosis of large vessels group, and 20.9% in the microangiopathy group. Overall, 127 patients (18.4%) had a family history of coronary disease, and 113 had a family history of cerebrovascular disease.
Table 1. Risk factors among stroke subtypes, %
TOAST, n Males, % Females, % Age .65 years, % Hypertension, % Diabetes, % Dyslipidemia, % Smoking, %*
Macroangiopathy
Cardioembolism
Microangiopathy
Other etiologies
Unknown
223 47.5 52.3 63.2 80.7 26.9 57.8 29.1
195 46.7 53.3 56.9 69.7 18.5 40 16.9
127 50.4 49.6 72.4 92.1 27.6 50.4 29.1
30 26.7 73.3 13.3 43.3 10 23.3 13.3
113 52.2 47.8 54.9 62.8 10.2 40.7 22.1
*Includes patients who were smokers and stopped smoking cigarettes within the previous 5 years.
P
.153 ,.001 ,.001 ,.01 ,.03 .014
L.C. PORCELLO MARRONE ET AL.
34
Table 2. Stroke subtypes in South American, studies % Study location
n
Porto Alegre Guayaquil2 Santiago6 Buenos Aires7 Bogota8 Santiago9
688 313 233 250 119 110
Macroangiopathy Cardioembolism Small-vessel occlusion Other etiology Undetermined etiology 32.4 7.4 33.5 12 19 7
28.3 14 32.6 21 18 14
Discussion Our study was conducted exclusively with patients who were admitted to the emergency department with signs of acute stroke, which possibly confers a more serious character to the group selected for study. A previous study that assessed differences in risk factors between hospitalized patients and nonhospitalized patients found no differences between the 2 groups in terms of the subtype of ischemia and the prevalence of risk factors.16 The hospitalized patients had a higher prevalence of cardioembolic phenomena of ischemia and a lower prevalence of microangiopathy.16 In an evaluation of 5017 patients with stroke in Germany, the most common subtype was cardioembolic (25.6%), followed by unknown etiology (22.7%), macroangiopathy (20.9%), microangiopathy (20.5%), concurrent etiologies (6.9%), and other causes (3.5%).10 In a French study that analyzed 332 patients with ischemic stroke, the distribution of ischemic stroke subtypes was 119 (35.8%) large-artery atherosclerosis, 89 (26.8%) small artery occlusion, 81 (24.4%) cardioembolism, and 43 (13%) other and undetermined causes.11 Overall, the most frequent vascular risk factor was hypertension, with a total prevalence of 62%. In Spain, Moreno et al15 studied 615 patients (307 controls) and found that hypertension was the most prevalent risk factor in all stroke subgroups, followed by smoking (which is more closely associated with atherothrombotic types) and other unspecified causes. When analyzed separately by sex, men had a higher prevalence of smoking and dyslipidemia than women, whereas women had more hypertension than men, and diabetes had a similar prevalence in men and women. In that study, the atherothrombotic subtype was the most prevalent (32.5%), followed by indefinite (29.2%), cardioembolic (18.5%), lacunar (16.6%), and other etiologies (3.2%).15 Sacco et al17 reported racial-ethic–based differences in age in their cohort, with whites having an older age at stroke compared with blacks and Hispanics. Differences in other risk factors are also reported among these groups.17 The South American population is heterogeneous and includes native Indians, immigrants of all races, and a number of racial admixtures. Porto Alegre in southern
18.5 43.1 14.1 42 19 43
4.4 6 5.2 6 8 6
16.4 29.5 14.6 18 21 29
Brazil has a population of approximately 1.4 million, composed of immigrants of various ethnic origins. Studies of stroke incidence in South America have yielded rates ranging from 0.35 to 1.83 per 1000 population.18-20 However, in some regions of Brazil, stroke is the leading cause of death and disability. Although stroke is the leading cause of death in South America, little data are available on the epidemiology of stroke subtypes. The most important South American studies are listed in Table 2. In summary, we found differences in the prevalence of major risk factors among the stroke subtypes, demonstrating that knowledge of pathophysiology is essential for the proper management of these patients. Given this, learning more about the epidemiologic data of the region is vital. In this study, the most prevalent risk factors were hypertension and dyslipidemia, and the most common etiology was large-artery atherosclerosis. The differences between our findings and those of previous studies may be attributed to variations in the patients samples in terms of age, sex, race, and socioeconomic conditions, and whether or not the patients were admitted to the emergency department.
References 1. Saposnik G, Del Brutto OH. Stroke in South America: A systematic review of incidence, prevalence, and stroke subtypes. Stroke 2003;34:2103-2107. 2. Del Brutto OH, Mosquera A, S anchez X, et al. Stroke subtypes among Hispanics living in Guayaquil, Ecuador: Results from the Luis Vernaza Hospital stroke registry. Stroke 1993;24:1833-1836. 3. Hassaballa H, Gorelick PB, West CP, et al. Racial differences in the trial of danaparoid in acute stroke (TOAST). Neurology 2001;57:691-697. 4. Bonita R. Epidemiology of stroke. Lancet 1992;339:342-344. 5. Adams HP, Bendixen BH, Kappelle LJ, et al. Classification of subtype of acute ischemic stroke: Definitions for use in a multicenter clinical trial. Stroke 1993;24:35-41. ~ ez L, Arriagada C, et al. 6. Nogales-Gaete J, N un Caracterizaci on clınica de 450 pacientes con enfermedad cerebrovascular ingresados a un hospital p ublico durante 1997. Rev Med Chil 2000;128:1227-1236. 7. Saposnik G, Caplan LR, Gonzalez LA, et al. Differences in stroke subtypes among natives and caucasians in Boston and Buenos Aires. Stroke 2000;31:2385-2389. 8. Pe~ na I, Ruiz C, Morillo LE, et al. Clasificaci on del TOAST en la pr actica clınica de un hospital universitario. Acta Neurol Colomb 2001;17:304-308.
STROKE SUBTYPES IN BRAZIL 9. Diaz V, Plate L, Erazo S, et al. Prevalencia de la ateromatosis carotıdea en pacientes con enfermedad cerebrovascular oclusiva. Rev Med Chil 2001;129:161-165. 10. Grau A, Weimar C, Buggle F, et al. Risk factors, outcome, and treatment in subtypes of ischemic stroke: The German Stroke Data Bank. Stroke 2001;32: 2559-2566. 11. Giroud Rouaud M, Osseby G-V, Durier J, et al. Ischemic stroke subtypes and associated risk factors: A French population-based study. J Neurol Neurosurg 2008; 12:1344-1348. 12. Biller J, Love BB. Vascular disease of nervous system. In: Bradley WG, Daroff RB, Fenichel GM, et al, eds. Neurology in Clinical Practice. Philadelphia: Butterworth Heinemann, 2004:1197-1249. 13. Arboix A, Rivas A, Garcia-Eroles L, et al. Cerebral infarction in diabetes: Clinical pattern, stroke subtypes, and predictors of in-hospital mortality. BMC Neurol 2005;5:9. 14. Jackson C, Sudlow C. Are lacunar strokes really different? A systematic review of differences in risk factor
35
15.
16.
17.
18.
19.
20.
profiles between lacunar and nonlacunar infarcts. Stroke 2005;36:891-904. Moreno VP, Garcia-Raso A, Garcia-Bueno MJ, et al. Factores de riesgo vascular en pacientes com ictus isquemico: Distribuci on seg un edad, sexo y subtipo de ictus. Ver Neurol 2008;46:593-598. Schulz UGR, Rothwell PM. Differences in vascular risk factors between etiological subtypes of ischemic stroke. Stroke 2003;34:2050-2059. Sacco RL, Kargman DE, Zamanillo MC. Racial-ethnic differences in stroke risk factors among hospitalized patients with cerebral infarction. Neurology 1995;45:659-663. Jaillard AS, Hommel M, Mazetti. Prevalence of stroke at high altitude (3380 m) in Cuzco, a town in Peru: A population-based study. Stroke 1995;26:562-568. Uribe CS, Jimenez I, Mora MO, et al. Epidemiologıa de las enfermedades cerebrovasculares en Sabaneta, Colombia (1992–1993). Rev Neurol 1997;25:1008-1012. Pradilla G, Pardo CA, Daza JS, et al. Neuroepidemiologıa en Colombia: Estudios en 16,032 individuos. Acta Neurol Colombiana 1995;11:129-133.