INTRODUCTION

Stroke is defined as a focal neurological deficit lasting for more than 24 hours having a vascular aetiology. It is a common neurological disorder being second leading cause of death in the world and third leading cause of disability (11). Stroke is caused by the sudden death of brain cells due to the lack of oxygen when the blood flow to the brain is lost by block or rupture of the artery of the brain. It is also a leading cause of depression and dementia. Globally, 70% of the strokes and 87% of both stroke-related deaths and disability-adjusted life years occur in low and medium-income countries (LMIC).

During these decades, the western countries have seen a decline in stroke while the LMIC have seen an upsurge of stroke. The occurrence of stroke is 15 years earlier and causes more deaths of people who are living in LMIC. Strokes mainly affect the individuals who are the most productive of a nation. It is impacting the gross domestic product (GDP) of a nation and the growing crisis has gathered less attention which is unfortunate (11).

Stroke in sub-Saharan Africa is a major public issue. It has been documented to have higher mortality than the developed countries. Rural south Africa is seeing a flurry of cases. According to the latest world health organization (WHO), data published in 2017 Stroke Deaths in the Central African Republic reached 3,899 or 6.26% of total deaths. The age-adjusted Death Rate is 155.11 per 100,000 population and the Central African Republic ranks #13 in the world (8). The aetiology of these strokes is hypertension, diabetes mellitus (DM), alcohol intake, smoking, diet/nutrition, and human immunodeficiency virus (HIV). Several non-modifiable factors such as age, gender, ethnicity, race, and hereditary have also been identified (4). The incidence of ischemic strokes is higher than the haemorrhagic ones. Ischemic strokes account for 80-85% of the burden while the rest is 15-20% is haemorrhagic (3).

In Africa, most people live in rural areas, where poverty, illiteracy, unavailability, and lack of good care facility play’s an important role in the outcomes of stroke. Since limited publications exists defining the stroke subtypes and epidemiology. This study aims to retrospectively review the data of patients admitted to our in-patient and out- patients visiting the department of neurology for determining the epidemiology of stroke and their sub-types with further details about the aetiology pertaining to the strokes.

MATERIAL AND METHODS

We carried out a retrospective study of all the patients who had a clinical diagnosis of stroke with neurological deficit and pointing to a vascular cause as confirmed by computerized tomography (CT) or magnetic resonance imaging (MRI) of the brain. Transient ischemic attack (TIA), which is a transient neurological deficit with recovery in 24 hours was excluded from the analysis. We are tertiary care centre located in the DRC.

DRC is a sub-Saharan African country despite its natural worth in billions due to the presence of precious metals. The eastern Congo is unstable while Kinshasa is modern and bustling. The data was collected between April 2014 and August 2015. The data was collected on the hospital information data system (HIS) and later was manually entered into data spreadsheets and evaluated.

The basic demographics, stroke subtype as confirmed by CT/MRI, potential risk factors, socio-economic information were all collected and reviewed. Also, neurological examination findings at admission, haematological and biochemical results were reviewed. The haematological and biochemical parameters were not available in all the cases which potentially limited our review to only the risk factors, clinical features, and type of the stroke. The demographics and risk factors collected and reviewed were as follows: Age, gender, chronic arterial hypertension, type 2 diabetes mellitus (T2DM), cigarette smoking, alcohol intake, and presence of obesity. The strokes were divided into ischemic and haemorrhagic followed by Stroke Project Classification subtype of all ischemic strokes. On CT/MRI, lacunar stroke (LACI) was seen as a small, round, hypodense/hypointense lesion of ≤ 25 (mm) along the course of penetrating arteries or deep vessels while non-lacunar infarct was defined as a large area of hypodensity/hypo intensity involving large vessel in the region of the vascular territory. The strokes were divided into LACI, total anterior cerebral infarction (TACI), partial anterior cerebral infarction (PACI), posterior circulation infarcts (POCI) were identified as non-lacunar circulation infarcts. (4) The data were analysed using the SPSS software version 25.0 for windows. Descriptive and frequency statistics were obtained for the variables of interest. Chi-square was used to test for statistical significance between categorical variables. A p-value of less than 0.05 was deemed as significant.

RESULTS

Out of the total patients visiting the department of neurology between May 2014 and July 2015; 70 patients had met the criteria for the clinical definition of stroke with the presence of a radiological diagnosis. The total number of patients reviewed in the department of neurology in the same period was 1021, among these a total of 6.86 % of neurological visits were attributed to stroke.

The age of the patients ranged from 20-80 years with a mean age of 55 years. Males accounted for 67.1% of the cases and the rest were females. The male: female ratio was 2:1. Table I provides the distribution of patients according to age group and sex.

The incidence of ischemic stroke was higher than the haemorrhagic stroke, lacunar infarction was the most common type of stroke seen in 39 (55.7%) patients as compared to the non-lacunar in 27(38.6%) patients as shown in the table II.

The various complex clinical features observed in patients were divided into hemiparesis/hemiplegic, monoparesis/monoplegia, speech disorders(aphasia/dysarthria), seizures, and others which includes visual disturbance, dementia, cranial nerve deficits (facial palsy), sensory symptom (hyperaesthesia / Tingling) dizziness, loss of consciousness and vomiting. The table III highlights the clinical presentation of strokes.

The risk factors are presented in Table IV, hypertension 58 (82.86%) emerged as the most common risk factor followed by the history of alcohol intake 58 (82.86%). Others include T2DM 15 (21.43%), coronary artery disease (1.43%), arrhythmias 4 (5.71%). Smoking was significantly noted in 3 (4.29%) patients with an active history of smoking and 12 (17.14%) with a history of smoking.

Table V shows the stratification of classes of the patients, dividing them into upper and lower socioeconomic status, using their occupation and education levels. 33 (47.14%) patients belonged to the high socio-economic class while 37 (52.86%) belonged to the low class, though data was missing for one patient only.

Obesity is defined as a body mass index (BMI)of ≥ 30, the data shows 13 (18.57%) out of the 70 patients were found to be obese, although data was found missing in one patient. Dyslipidaemia was found as one of the risk factors seen in patients with stroke. In this study, the full lipid profile panel was not done due to financial constraints, hence the LDL data was available and extracted for identifying dyslipidaemia patients. Furthermore, dyslipidaemia was defined as an abnormality in LDL. The data shows 41 (58.5%) patients had their lipid profile data and 6 (8.57%) had dyslipidaemia.

The radiological evaluation of the stroke patient in these studies shows, most of the patients underwent a brain scan, either brain CT or brain MRI or both, and 6 patients were found without a CT scan, although meets clinical criteria of stroke. The Data reveals 51 (72.86%) patients out of the 70 patients had a CT scan brain done, while only 19 (27.14%) were found to have done the MRI brain Scan, most probably due to cost constraint as shown in Table VI. The findings in the radiological investigations show 39 (55.7%) number of patients had lacunar infarction and 27 (38.6%) had non-lacunar infarction. The site of lesion was in middle cerebral artery territory (corona radiata, globus pallidus, caudate, putamen), lenticulostriate, internal capsule, and thalamic for lacunar infarct vs parieto-occipital and cortical for non-lacunar type. This was most often found in the parietal lobe.

In the etiological evaluation, 8 (11.43%) patients were found to have a history of TIA. 70 patients had data of blood pressure (BP) available, and the mean BP was 146/86 mmHg and mean pulse rate was 73.

DISCUSSION

The burden of the stroke and its related risk factors, complications, and outcomes are not very well studied in DRC. In this regard, our retrospective study holds an important goal to report the burden of stroke along with its risk factors, complications, and outcomes in DRC. In our study among all the patients reviewed in the neurological department, 6.86% of visits were attributed to stroke. These results are similar to other studies conducted across various African countries (6).

Our study shows a higher frequency of stroke in males (61.7%) than females with male to female ratio of 2:1. The ratio is similar to the 3 studies conducted around the African and Arabian population which clearly showed male dominance (4,10), but different from 2 south Nigerian studies showing female predominance. (7,8).

Among these women, 47.8% were above the age of 65, these results can be efficiently supported by a study by Ajayi AO which states that patients with higher education and male gender are more aware of their increased risk factor for stroke than female gender and undereducated patients (1). Our study shows the prevalence of stroke is similar in both upper and lower socio-economic societies in and around DRC, which is in contrast with a study conducted in rural southwestern Nigeria (2,8) showing a higher prevalence of stroke (84.2%) among the lower socio-economic population of Nigeria. Our study also reported a significantly higher incidence of ischemic stroke (93.4%) than haemorrhagic stroke (5.7%), these findings align with other studies conducted across the African continent (8,10). Among the subtypes of ischemic stroke, lacunar subtype was more frequent (55.75%) than the non-lacunar subtypes (38.6%) which is similar to the previous study conducted in Kinshasa city in the year 2011-2012 (12). Our study also reported alcohol consumption as a significant (p=0.003) risk factor related with both the subtypes of ischemic strokes.

In our study, Hypertension was the most common risk factor of stroke (81.69%) followed by alcohol intake (71.83%), which is closer to various studies conducted in and around Africa (4,10,11). The risk is strongly related to both systolic and diastolic blood pressure besides, the risk for first-ever stroke or recurrent stroke appears to be log-linear throughout normal ranges. A rise in 10 mmHg in the mean arterial pressure leads to about 20-30% increase in stroke risk (11).

Cigarette smoking is also one of the risk factors (16.9%) among our patients. This rate of smoking is higher than 11.3% in another study in Nigeria (7) and 6 % in Saudi Arabia but far less than 44% in Pakistan (5,8). The effect of smoking has been said to be dose-related, heavy smokers are more likely to develop stroke, however, the risk of having the disease reduces with smoking cessation.

In our study, 21.13% of patients were reported to have diabetes mellitus, as diabetes mellitus is a major risk factor for atherosclerosis and the excess risk of stroke in patients with diabetes mellitus is about four times higher when compared with normal individuals in a general population. Therefore, it is vital to ensure good glycaemic control in those with the condition to prevent the development of stroke. In the management of stroke, it is necessary to address all the risk factors and not just focus on few ones.

This was a retrospective study and, as such have certain inherent limitations, such as poor or incomplete medical record-keeping, missing data, and lack of essential, specific diagnostic facilities, as well as poor follow-up clinic visitation, and under-reporting of death after hospital discharge. Despite these limitations, we have been reviewing the pattern of stroke in the semi-urban population of the Democratic Republic of Congo.

CONCLUSION

The overall prevalence of stroke was found to be 6.86%, with a distribution of 2:1 in males and females, respectively. Ischemic stroke was significantly more frequent (94.3%) than haemorrhagic stroke. Hypertension, higher alcohol intake, smoking habit, obesity, and dyslipidaemia are significant risk factors of stroke in an African population. The establishment of practical guidelines for prevention, earlier detection, treatment, and control of stroke in primary health settings is a vital and necessary step. However, primary, secondary, and tertiary health services need to be advised to better suit the care for non-communicable diseases in low resources settings in the semi-urban community of the Democratic Republic of Congo.

TABLE I:  Age and gender breakdown in patients.

TABLE II: Types of Stroke

TABLE III:  Clinical Features of Stroke

 *Other symptoms (sensory /dizziness/ cranial nerve deficits /memory issues/visual loss/headache).

TABLE IV: Identified modifiable risk factors for stroke.

 TABLE V:  Socioeconomic status in stroke patients 

 TABLE VI:  Radiology investigations in stroke patients reviewed

Table VII: Factors associated with the subtype of Ischemic Infarct.