Ischemic Stroke in Women Admitted in a Tertiary Hospital in Burkina Faso

Objective: The objective of this study is to determine the characteristics of ischemic stroke in Women and to compare vascular risk factors, stroke severity and clinical outcome between patients aged under and older 50 years in a tertiary hospital in Burkina Faso. Methodology: We conducted a cross sectional retrospective study on ischemic stroke in adult female patients (≥15 years) admitted in the neurology department of youth from January 1, 2008 to December 31, 2017. Results: During study period, ischemic stroke accounted for 57.6% of all stroke. The mean age of women was of 58.88 (± 17.13) years. About 72.2 % of women was aged over 50 years. Hypertension was the most vascular risk factors (69.7%), followed by dyslipidemia (33.6%) and alcohol consumption (32.7%). Oral contraception pills (8.5%) was the most sex related factors followed by migraine (4.6%) and pregnancy or post-partum state (1.8%). The delay of arrival at emergency department was 4.69 days. At admission, 68% of women had severe neurological deficit (NIHSS ≥ 15). The most common causes of stroke were large vessel disease (37.7%), cardio embolic stroke (20%) and small vessel disease (9.5%). Length of stay was 14.21 days with 15.1% of mortality. Functional outcome at discharge was worse (mRS˃2) in 79.6%of women. After bivariate analysis, hypertension, tobacco use, physical inactivity and diabetes mellitus were most frequent in older women (p=0.0001). Oral contraceptive pill, migraine, HIV and pregnancy were most frequent in young women (p˂0.05). Conclusion: There was a long delay between stroke onset and hospital admission. Hypertension was the most vascular risk factor in older women. The majority of women had severe stroke at admission and worse outcome at discharge.


Introduction
Stroke is emerging as a leading cause of preventable death and disability worldwide [1]. Stroke is the first cause of death for women in France [2] and 60% of all stroke deaths involve women in Unites States [3]. If male sex has been considered a risk factor for stroke, females have a higher lifetime risk for stroke, are more likely to experience recurrent stroke, and are more likely to have more severe strokes [3]. Cohort studies indicate that women and men have differences in risk factor profiles [4,5] stroke presentation [4][5][6] and stroke etiology [7]. Women under age 50 are generally considered to have a lower incidence and prevalence of stroke than men [8]. With the exception of subarachnoid haemorrhage, there is little evidence of sex differences in stroke subtype. While Africa appears to have the highest incidence, prevalence and case fatality of stroke [9][10][11][12], there are few studies regarding stroke in women [13][14][15]. In Burkina Faso, there is no adequate data on ischemic stroke in Women. The objective

Study profile
We carried a cross-sectional study at neurology department of Yalgado Ouedraogo University teaching hospital during the period from 1 January 2008 to 31 December 2017.

Population selection
Adult women patients (≥15 years) were included in this study. Women were classified into young women (15-49 years) and old women (≥50 years). Women with incomplete medical records were not included in this study.

Assessments
The risk factors of stroke were defined in terms of hypertension, diabetes mellitus, physical inactivity, obesity, migraine, HIV infection, pregnancy, dyslipidemia, alcohol and tobacco consumption, ischemic heart diseases, valvular heart disease, history of transient ischemic attack or stroke, smoking and oral contraceptive pill. Hypertension was diagnosed if the patient had a history of hypertension, or if the blood pressure exceeded 140 (systolic) and/or 90 (diastolic) mmHg during hospitalization, or if the patient was receiving antihypertensive drugs. Diabetes Mellitus was diagnosed based on history and fasting serum glucose levels (110 mg/dl), or if the patient was receiving insulin or hypoglycemic drugs. Stress hyperglycemia was defined if patient had glycemic level>6.1 mmol/l at admission. Hyperlipidemia was defined as fasting total blood cholesterol ≥ 5.65 mmol/L (2.20 g/L) and/or LDL-cholesterol ≥ 4.1 mmol/L (1.6 g/L) and/or triglyceride ≥ 1.6 mmol /l (1.35 g/L). Alcohol users were categorized into current users (users of any form of alcoholic drinks). Smoking was defined if patient say his smoking 10 cigarettes/day. Anemia was defined as hemoglobin levels 11 g/dl. Neurological deficit was defined as severe if NIHSS>15. Some investigations like brain CT, cervical ultrasound and Lipid profile were done in all cases. In some selected cases blood sugar, ECG, Echocardiography, lumbar puncture with CSF analysis, VIH test were done. We used the criteria of the NASCET, et al. [16] to define the degree of carotid stenosis in 3 categories (<50 %; 50-69%; >70 %). Stroke was attributed to pregnancy or postpartum state if it happened during pregnancy or within 1 month after delivery. The stroke mechanism was classified into 5 categories according to the TOAST criteria: (1) small-vessel occlusion, (2) large-artery atherosclerosis (LAA), (3) cardioembolism, (4) stroke of other determined etiology, (5) stroke of undetermined etiology. The outcome was classified according to the modified Rankin score (mRS).

Data collection and analysis
Data collection: Data were collected through a questionnaire by doctoral student in medicine and verified by us before inclusion. Questionnaires were checked for the completeness of information by us. The variables considered were socio demographic data (age, gender, profession, marital statutes, and residence), clinical data (complaints at admission, vascular risk factors, blood pressure at admission, stroke severity ( Score de Glasgow, NIHSS at admission, Rankin score at discharge), paraclinical data ( stroke subtype, stress hyperglycemia, lipid profile, presence of athermanous plaque at cervical ultrasound, abnormalities at electrocardiogram and echocardiography), therapeutic data ( anticoagulant agents, antiagregant agents, statins).
Data analysis: Once the information was found to be complete, then it was fed into Epi-Info version 7.2.2.6 for data analysis. Mean and percentages were analyzed by Chi-square tests for large numbers and the exact Fischer test for small numbers. The test is considered statistically significant for p less than 0.05.

Vascular risk factors
Hypertension was the most sex-non-specific modifiable risk factors accounting for 69.7% of cases, followed by dyslipidemia (33.6%) and alcohol consumption (32.7%). According to sex-specific risk factors, oral contraceptive pill, migraine and pregnancy or post-partum state was respectively present in 25(8.5%), 13(4.6%) and 5(1.8%) patients. Twenty (7%) women had history of cesarean delivery and 4(1.4%) history of hysterectomy. After bivariate analysis, hypertension, tobacco use, physical inactivity and diabetes mellitus were most frequent in older patients (p=0.0001) while oral contraceptive pill, migraine, HIV infection and pregnancy were most frequent in young patients (p<0.05).

Investigations
Brain CT was performed in a delay of 2.06 ± 0.7 days after stroke onset (Ranges 1-5 days). The middle cerebral artery was the most represented (71.5%), followed by cerebral anterior artery (25.7%) and posterior circulation stroke (14.4%). There was significant link between involvement in ACA and old age (p=0. 0424). According to lipid profile, 95(33.5%) women had dyslipidemia. Among them, 30(10.56 %) had high level Cho (Total Cholesterol), 25(8.8%) had high level of LDL c and 20( ) had high level of TG. There was no difference between lipid profile and age group (p>0.05). Blood glucose was measured in 207(72.9%) patients. Of whom, 110(53.1%) women had stress hyperglycemia (>6.1 mmol/l). Stress hyperglycemia was most common in older patients than in young patients (p=0.

Discussion
Among women, ischemic stroke was the most prevalent stroke subtype with similar prevalence (57.6%) than in a study from Sudan (59.2%) [14].

Sociodemographic characteristics
The mean age of women with ischemic stroke (58.88 ± 17.13 years) was similar than in others stroke studies in Africa, particularly in Nigeria (55.6 ± 12.4 years) [15] and in Senegal (63 years) [17]. This two studies concerned all stroke subtype in women. The age of women with ischemic stroke is elevated in Spain (76.02 ± 12.93 years) [18], in Brazil (71.5 years) [19] and in France (72.9 years) [17]. The younger age of women could be explained by the low life expectancy in our context. The majority of ischemic stroke (72.2 %) occurred in older patients, in line with the study of Leonardo in Brazil [19].

Vascular risk factors
Hypertension was the most vascular risk factor in women with ischemic stroke (69.71%). Similar descriptions were observed by Caso V, et al. [18] in Spain (75%), Forster (83.8%) [20], and Musa in Nigeria (83.3%) [15]. The prevalence of Diabetes mellitus was lower than in the study of Gu in China: 15.9% versus 24.3% [21]. According to age group, hypertension and diabetes mellitus had significant role in the developing of ischemic stroke in older women, in concordance with several studies [22][23][24]. In contrast, oral contraceptive pills had significant role in developing of ischemic stroke in young age, as in literature [24]. The use of Contraceptive pills in young women was relatively less common in our study (8.8%) than in a study from Senegal (20.8%) [13]. HIV infection was identified as vascular risk factor. The increase in stroke risk was most pronounced in HIV-infected women and in younger age groups [25]. In our study, there was significant link between HIV and young age in the development of ischemic stroke in young women in our context (Tables 1 and 2).

Symptomatology
According to time arrival at ED, all the patients were admitted after thrombolysis delay (4h 30mn). This observation was consistent with several studies witch report longer times from symptom onset to emergency department (ED) arrival for women [26][27][28]. About seventy percent of women had severe stroke at admission (NIHSS>15), higher than in the study of GU (6.9%) [21] and Ong (20.9%) [29]. Women had higher NIHSS at admission (14.77) than in Spain (9.4 ± 6.94) [18] and China (5.4 ± 5.6) [21]. The high severity of stroke in Women could be explained by many factors, as socio-financial constraints, problem of transportation and absence of pre-hospital care facilities for stroke patients.

Stroke investigations
Stroke investigations available in all our patients. The biological assessment had found that stress hyperglycemia was prevalent in women at admission (53.1%). In our study, women aged over   Journal of Neurology and Neurobiology Open Access Journal 50 years old had more stress hyperglycemia than young women. Hyperglycemia affects elderly AIS patients more deeply than younger AIS patients [30]. According to imaging findings, middle cerebral artery was the most involved in women (71.5%), in concordance with Fromm's study [31]. The involvement of ACA (25.7%) was relatively important in comparison with literature in which it's ranging from 1.1% to 2.3% [32]. Indeed, our study found a significant link between ACA involvement and older age in women stroke. Up to date, there are no published study in literature that analysed the link between stroke territory and age group in Women. TOAST Classification showed that large vessel disease was the most finding (37.7%), followed by unknown cause (25.4%) and cardio embolic cause (20%). This figure is different in the study of Caso in which cardio-embolic stroke was the leading cause (30%) [18]. The frequency of stroke with unknown origin (25.4 %) was similar than in literature (25-30%) [33]. This cause was most common in older women (28.3 %) than in young women. Stroke investigations were less frequent in older patients. Large vessel disease was significantly most common in older women. Many studies have shown that ECAS distributed more in older ages than in young ages [34]. The frequency of Large vessel disease in young women (22.4%) was similar than in young Asians women (24%) [35]. The frequency of Cardio-embolic stroke in young women (19%) was similar than in the study of Wassay in Asia (19%) [35]. This frequency seen to be high in our context because most women did not done some cardiovascular investigations (Holter ECG, Esophageal cardio echography). sVD (small vessel disease) play in important role in the development of cognitive impairment. Its frequency was relatively important in young women (11.4%) than in old women (8.8%) but there are no relationship with SVD and age group. In young women, the frequency of SVD was similar than in the study of Wassay (15%) [35]. This low frequency is due to the fact that Nuclear Magnetic Resonance Imaging of the brain was not common use in our context. There was relationship between others causes represented by angiitis and young age. The frequency of angiitis in young patients (16.5) was relatively higher than in the study of Wassay (11.4%) [35]. In Africa, there are not sex difference between HIV status and stroke [15] (Tables 3 and 4).

Treatment and in-hospital outcome
Stroke treatments do not differ according to the age group. Antiaggregant agents was the leading treatment (94%), in line with a study from China (100%) [21]. The majority of women were treated with antidepressive drug (51.7%). Women seem to have twice more likely to experience post-stroke depression than men [36]. The length of stay was longer than in a study from Croatia (14.21 days vs. 5.4 days) [37]. Functional outcome at discharge was particularly worse in our context (79.6%), comparatively to the study from China (10.8%) [21]. Case fatality rate was higher (15.14%) than in the study of Ong (4.55%) [30]. This large proportion of unfavorable outcome could be explained by the longer time of admission, the severity of stroke and the high frequency of stress hyperglycemia among the patients. Post stroke pneumonia was the most common complication during hospitalization (20%), particularly in older women. Post stroke pneumonia and urinary tract infections were less frequent among young patients [32]. The high mortality is due to the absence of stroke unit in our hospital (Tables 5 and 6).

Study limitations
This study had several limitations regarding to study profile. It was single hospital based study, so we can't generalize the results at all the patients admitted in Yalgado Ouedraogo Hospital. Second, our study did not compare sex difference in ischemic stroke by including a control group of men.

Conclusion
There was a long delay between stroke onset and hospital admission. Hypertension was the most vascular risk factor in older women. The majority of women had severe stroke at admission and worse outcome at discharge. There was difference with the group according to the frequency of hypertension, diabetes mellitus, contraceptive use and stroke etiologies.