(Stroke. 1995;26:1995-1998.)
© 1995 American Heart Association, Inc.
Articles |
Stroke in Young Black Patients
Risk Factors, Subtypes, and Prognosis
From the Department of Neurology, Emory University School of Medicine, Atlanta, Ga.
Correspondence to Michael R. Frankel, MD, Department of Neurology, Grady Memorial Hospital, BG 03, 80 Butler St SE, Atlanta, GA 30335.
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Abstract |
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Background and Purpose Stroke subtypes and prognosis differ among older black patients compared with whites; however, few data are available regarding stroke among young black patients.
Methods To determine the risk factors for stroke, stroke subtype, and prognosis among young black patients, we retrospectively reviewed the medical records of all 15- to 44-year-old patients admitted with stroke to a university-affiliated public hospital from January 1990 through June 1994.
Results Of the 248 eligible patients admitted with stroke, 219 were blacks. Hypertension was more frequently associated with stroke in young black than in non-black patients (55% versus 24%, P=.003). Cocaine abuse was frequent among both black and non-black patients (27% versus 38%, P=NS). Hypertensive intracerebral hemorrhage (64%) was the most common subtype of intracerebral hemorrhage (n=67), and lacunar infarction (21%) was the most common subtype of cerebral infarction (n=112) in young black patients. Outcome in black patients with stroke at discharge was 69% independent, 8% dependent, and 23% dead.
Conclusions The high frequency of hypertension, hypertensive intracerebral hemorrhage, and lacunar infarction among young black patients with stroke suggests accelerated hypertensive arteriolar damage, possibly due to poor control of hypertension.
Key Words: blacks • cocaine • hypertension • young adults • prognosis
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Introduction |
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Many reports have suggested that the risk of cerebrovascular disease differs between blacks and whites.1 2 3 In addition, significant racial differences have been found in the types and prognosis of stroke.4 5 6 At younger ages, the risk for subarachnoid hemorrhage (SAH) and intracerebral hemorrhage (ICH) is higher in blacks than in whites.7 8 However, because previous studies of stroke in young adults have primarily included whites,9 10 11 12 13 few data exist regarding stroke risk factors and subtypes in young black patients.
To examine risk factors, subtypes, and prognosis of stroke in young black patients, we undertook a retrospective study of stroke in our university-affiliated public hospital, which serves a predominantly black population.
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Subjects and Methods |
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TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
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Patients
We studied all 15- to 44-year-old patients with stroke admitted to Grady Memorial Hospital in Atlanta, Ga, between January 1, 1990, and June 30, 1994. Eligible patients were identified by computerized search of all discharges with International Classification of Diseases, 9th revision, (ICD-9) codes 430, 431, 432, 433, 434, 436, and 437. The discharge transcription of each patient was reviewed. We excluded patients with transient ischemic attacks and stroke related to trauma and patients in whom further evaluation excluded a vascular event.
Data Collection
We collected the following information from each eligible
patient's discharge transcription: (1) age, sex, and race as
determined by the triage clerk; and (2) the risk factors present
before onset of stroke (mentioned in the discharge transcription), eg,
hypertension, diabetes mellitus, currently smoking, use of cocaine,
notation of alcohol abuse, history of stroke in first-degree
relatives at age less than 55 years, and history of heart disease
associated with stroke such as atrial fibrillation, congestive heart
failure, valvular lesions, and others.14 In women
with cerebral infarction, information regarding pregnancy and use of
oral contraceptives was also determined. We attempted to obtain
information not mentioned in the discharge transcription by reviewing
previous discharge summaries, results of previous laboratory tests, and
the pharmacy record from preceding clinic visits. The information
was presumed to be absent if we were unable to find clear
documentation.
Subtype Classification
One neurologist (A.I.Q.) classified all strokes into cerebral
infarction, ICH, or SAH subtypes. The definitions of cerebral
infarction and ICH were based on the criteria of the National Institute
of Neurological Disorders and Stroke.15 SAH was defined
using the criteria published by Broderick et al.7 Each
patient with a cerebral infarction was further classified into one of
nine categories according to the classification used by the
Baltimore-Washington Young Stroke Study.14 ICH was further
classified into the following categories: (1) hypertensive ICH (defined
as the presence of at least two of the following features: history of
hypertension, markedly elevated blood pressure at
presentation, or location of ICH in typical sites for
hypertensive bleeding [basal ganglia, thalamus, or pons]); (2)
related to arteriovenous malformation; (3) secondary to
aneurysmal rupture; and (4) of undetermined etiology (defined
as ICH without typical features of hypertensive etiology and normal or
no angiograms). Classifications 2 and 3 were angiographic
diagnoses.
Prognosis
A modified Rankin Scale16 was used to assess each
patient's functional status at discharge. Patients with a Rankin score
of 3 or less at discharge were defined as independent. Mortality among
black and non-black patients during hospitalization was also
assessed.
Socioeconomic Status
To gain insight into the socioeconomic status of the patients,
we attempted to determine the insurance status at admission of all the
patients in this study.
Statistical Analysis
We performed univariate analysis with
EPI INFO 5.117 using the
2 method. We considered a value of
P<.05 as significant. Results are given as mean±SD.
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Results |
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TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
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We identified 298 patients by computerized search of all discharges with the above-mentioned ICD-9 codes. Patients with transient ischemic attacks (n=2), stroke related to trauma (n=21), stroke during hospital stay (n=3), and subdural hemorrhage (n=5) and patients in whom further evaluation excluded a vascular event (n=19) were not included in the analysis. A total of 248 patients of 15 to 44 years of age were admitted to our hospital with the diagnosis of stroke from January 1990 through June 1994. Each patient had a CT scan of the head at admission. Of these, 100 patients were further investigated with conventional angiography (39 patients with cerebral infarction, 21 with ICH, 38 with SAH, and 2 with venous thrombosis). Patients with cerebral infarction were also evaluated with transthoracic echocardiography (69 patients), transesophageal echocardiography (27 patients), carotid Doppler ultrasonography (35 patients), MR angiography (4 patients), and prothrombotic profile (58 patients, defined as measurement of proteins C and S, antithrombin III, and antiphospholipid antibodies). There were 219 blacks, 21 whites, 5 Asian Americans, and 3 others. The mean age of black patients was 37±5.9 years; 120 were men (cerebral infarction 53%, ICH 34%, SAH 12%, and venous thromboses 1%), 99 were women (cerebral infarction 50%, ICH 26%, and SAH 24%). The frequency of SAH was significantly higher among women than men (P=.04).
Risk Factors
The frequency of risk factors among young black patients according
to stroke subtype is shown in Table 1
. Preexisting
hypertension was the predominant risk factor among black patients with
ICH and cerebral infarction. Smoking and alcohol abuse were the next
most frequent risk factors for cerebral infarction. Cocaine use was the
most frequent risk factor in SAH and the second most frequent risk
factor in ICH patients. The frequency of hypertension was higher among
black than non-black patients (55% versus 24%, P=.003).
Cocaine use was similar in black and non-black patients (27% versus
38%, P=.3). Oral contraceptive use was seen in 6% of women
with cerebral infarction. Cerebral infarction occurred during the sixth
week of pregnancy in one woman.
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Subtypes of Stroke
The distribution of stroke subtypes among young black patients is
shown in Tables 2 and 3.
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Cerebral Infarction
Lacunar infarction due to small-vessel occlusive disease was
the most common stroke subtype identified. A potential cardiac source
for embolism was demonstrated on echocardiogram or
electrocardiogram in 22 patients (Table 2
). Seven cases of cerebral infarction were presumed to
be due to cocaine use in the absence of other probable causes. No
etiology was identified in 29 cases. Of these, 4 had a complete
evaluation with cerebral angiography, transesophageal
echocardiography, and a prothrombotic profile.
There were 31 cases of cerebral infarction in a small-vessel
distribution and 81 in a large-vessel distribution as determined by
clinical features and neuroimaging. Women were more likely than men to
have cerebral infarction in a large-vessel distribution (84%
versus 64%, P=.03).
Intracerebral Hemorrhage
Hypertensive hemorrhage was diagnosed in 43 patients.
Other etiologies are shown in Table 3. Six of the 15 patients without
an etiologic factor had normal angiograms.
Subarachnoid Hemorrhage
SAH was predominantly due to rupture of an aneurysm. No
etiology was determined in 8 patients, 4 of whom had normal
angiograms.
Prognosis
At discharge, 152 (69%) black patients were functionally
independent. The prognosis at discharge according to stroke subtype is
shown in the Figure. Regardless of stroke subtype, most
survivors were independent at discharge. Mortality among young black
patients was 23% (50 deaths). ICH was associated with a significantly
higher mortality than ischemic stroke (40% versus 12%,
P<.0001). There was a trend for higher mortality from SAH
than from cerebral infarction (26% versus 12%, P=.055).
There was also a trend for increased mortality among black women versus
black men with cerebral infarction (18% versus 6%, P=.09)
and SAH (37% versus 7%, P=.06). Mortality was similar
among black and non-black patients (23% versus 35%,
P=.26).
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Socioeconomic Status
Insurance information was available for 96% of the patients; of
these, 49% were uninsured. Medicaid (24%), Medicaid pending (8%),
Medicare (2%), and others (17%) were the main forms of insurance
among the patients.
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Discussion |
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TopAbstractIntroductionSubjects and MethodsResultsDiscussionReferences |
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This study provides a description of stroke in young black patients at a public hospital. The study highlights important information about stroke in patients with unique racial and socioeconomic characteristics. When compared with stroke patients from other studies,9 10 11 12 13 the young blacks at our hospital had prominent differences in stroke type and prognosis, as described below. These differences may be related in part to the socioeconomic status of the patients treated at our public hospital. Lack of insurance for many of our stroke patients reflects the low socioeconomic status of this population.
Previous studies have found hypertension to be the most prevalent risk factor for stroke among older black patients.8 9 18 19 Our study confirms that this is also true for young blacks and suggests that hypertensive arteriolar damage may be the major contributor to stroke in young blacks. Our findings on other risk factors predisposing blacks to stroke at a young age, such as smoking and alcohol use, are very similar to those of other studies.20 21 22 23 Cocaine use, which has recently been implicated in the pathogenesis of stroke,24 25 26 was prominent among both blacks and non-blacks with stroke and may reflect our urban population.27
This study also demonstrates a high proportion of ICH (30%) among young black patients with stroke. In European studies, ICH accounts for about 10% of all strokes in persons younger than 45 years.28 29 Furthermore, hypertension was the most common etiology (64%) of ICH in our patients. ICH in this age group in other populations is most commonly attributed to arteriovenous malformations,30 31 with hypertension accounting for only 15% to 30% of the cases.31 32 These differences may be related to uncontrolled hypertension and possibly cocaine use in our black patients.
Most ischemic strokes in young black patients were attributable to small-vessel occlusion. This finding differs from results of other studies in which most ischemic strokes in young adults are secondary to cardioembolism and dissection of large vessels.13 29 33 Previous studies have shown that blacks have more pronounced involvement of intracranial arteries and penetrating artery disease,34 35 possibly because of a higher frequency of hypertension and diabetes. The development of small-vessel occlusion at a young age in blacks may be due to an enhanced susceptibility to hypertensive arteriolar damage,36 early-onset hypertension, or delayed therapy.37
Previous studies have shown a mortality of up to 22% in young stroke patients, with 79% to 88% of the survivors having favorable outcome38 39 ; these findings are similar to our results. The good prognosis in survivors with stroke was independent of stroke subtype. The mortality due to ICH in our study (40%) was higher compared with other studies (21% to 24%).31 32 This might be related to the higher proportion of hypertensive ICH in our study. For reasons that are unclear, black women had a higher proportion of SAH and a trend toward higher mortality from cerebral infarction and SAH than black men. An increased subset of large-vessel-distribution cerebral infarction was seen in women and may be responsible for the higher mortality. More studies are required to understand these sex differences in stroke subtypes and prognosis in young blacks.
This study has certain important limitations. The results presented are representative of a public hospital serving a predominantly black population of lower socioeconomic status and therefore may not necessarily reflect the characteristics of patients at other hospitals. Furthermore, since this is a retrospective case series, certain variables such as alcohol and drug abuse may be underrepresented. Because transesophageal echocardiography, vascular imaging, and prothrombotic evaluation were not performed in all patients with stroke of undetermined etiology, our data may underestimate the frequency of cardioembolic strokes and strokes of other determined etiology.
Despite these limitations, we believe that accelerated hypertensive arteriolar damage may be the main risk factor for stroke in young blacks. This conclusion is based on the high proportion of black patients with hypertension, small-vessel occlusion, and ICH in our study. This hypothesis requires confirmation in a well-designed case-control study. In the meantime, we recommend that hypertension control and screening programs be directed to blacks beginning in their third and fourth decade of life to reduce the morbidity and mortality from stroke.
Received June 2, 1995; revision received July 31, 1995; accepted August 15, 1995.
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