Modifiable stroke risk factors in Africa: lessons from SIREN

Diabetes Mellitus as a risk factor for stroke among Nigerians: A systematic review and meta-analysis

Background

Diabetes mellitus is one of the modifiable risk factors for stroke. Stroke is common in Nigeria, but there is a paucity of national data on the frequency of diabetes in stroke. This study aimed to estimate to what extent diabetes a risk factor for stroke in Nigeria.

Methods

The study design is a systematic review, and the PRISMA guidelines were strictly followed. African Journal Online (AJOL), PubMed, SCOPUS and Google Scholar were systematically searched. The Newcastle-Ottawa scale was used to assess the quality, heterogeneity was determined with the I² statistic, and the DerSimonian Laird random effect model was selected for the meta-analysis.

Results

The studies were distributed across different regions of the country. The total sample size was 9397. The weighted average age of the patients with stroke was 53.7 years. The attributable risk of diabetes in stroke, among Nigerian patients, was 0.20 (95% CI: 0.17-0.22; p < 0.0001). The attributable risk has been rising steadily since the advent of the new century, and it is relatively higher in southern Nigeria.

Conclusion

The attributable risk of diabetes in stroke, among Nigerian patients is high. This varies across the regions but it is rising progressively nationally.

Incidence and characteristics of stroke in Zanzibar–a hospital-based prospective study in a low-income island population

Background

Stroke in adults is a critical clinical condition and a leading cause of death and disability globally. Epidemiological data on stroke in sub-Saharan Africa are limited. This study describes incidence rates, stroke types and antecedent factors among patients hospitalized with stroke in Zanzibar.

Methods

This was a prospective, observational study of stroke patients at hospitals in Unguja, Zanzibar. Socioeconomic and demographic data were recorded alongside relevant past medical history, medicine use and risk factors. The modified National Institute of Health Stroke Scale (mNIHSS) was used to assess admission stroke severity and, when possible, stroke was confirmed by neuroimaging.

Results

A total of 869 stroke admissions were observed from 1st October 2019 through 30th September 2020. Age-standardized to the World Health Organization global population, the yearly incidence was 286.8 per 100,000 adult population (95%CI: 272.4–301.9). Among these patients, 720 (82.9%) gave consent to participate in the study. Median age of participants was 62 years (53–70), 377 (52.2%) were women, and 463 (64.3%) had a first-ever stroke. Known stroke risk factors included hypertension in 503 (72.3%) patients, of whom 279 (55.5%) reported regularly using antihypertensive medication, of whom 161 (57.7%) had used this medication within the last week before stroke onset. A total of 460 (63.9%) participants had neuroimaging performed; among these there was evidence of intracerebral hemorrhage (ICH) in 140 (30.4%). Median stroke severity score using mNIHSS was 19 (10–27).

Conclusion

Zanzibar has high incidence of hospitalization for stroke, indicating a very high population incidence of stroke. The proportion of strokes due to ICH is substantially higher than in high-income countries. Most stroke patients had been in contact with health care providers prior to stroke onset and been diagnosed with hypertension. However, few were using antihypertensive medication at the time of stroke onset.

www.ClinicalTrial.gov registration NCT04095806.

Risk factors and outcomes of hospitalized stroke patients in Lusaka, Zambia

BACKGROUND

Limited data exists about stroke risk factors and outcomes in sub-Saharan African countries, including Zambia. We aim to fill this gap by describing features of hospitalized stroke patients at University Teaching Hospital (UTH), the national referral hospital in Lusaka, Zambia.

METHODS

We conducted a retrospective study of consecutive adults with stroke admitted to UTH's inpatient neurology service from October 2018 to March 2019. Strokes were classified as ischemic or hemorrhagic based on CT scan results and unknown if CT scan was not obtained. Chi-square analyses and t-tests were used to compare characteristics between cohorts with differing stroke subtypes.

RESULTS

Adults with stroke constituted 43% (n = 324) of all neurological admissions, had an average age of 60 ± 18 years, and 62% of the cohort was female. Stroke subtypes were 58% ischemic, 28% hemorrhagic, and 14% unknown. Hypertension was present in 80% of all strokes and was significantly associated with hemorrhagic stroke (p = 0.03). HIV was present in 18% of all strokes and did not significantly differ by stroke subtype. Diabetes (16%), heart disease (34%), atrial fibrillation (9%), and past medical history of stroke (22%) were all significantly more common in patients with ischemic stroke (p < 0.05). In-hospital mortality was 24% overall and highest among individuals with hemorrhagic strokes (33%, p = 0.005).

CONCLUSIONS

This Zambian stroke cohort is notable for its young age, significant HIV burden, high in-hospital mortality, and high rates of uncontrolled hypertension. Our results demonstrate Zambia's substantial stroke burden, significant contribution of HIV to stroke, and the need to improve primary stroke prevention.

Stroke in Africa: profile, progress, prospects and priorities

Stroke is a leading cause of disability, dementia and death worldwide. Approximately 70% of deaths from stroke and 87% of stroke-related disability occur in low-income and middle-income countries. At the turn of the century, the most common diseases in Africa were communicable diseases, whereas non-communicable diseases, including stroke, were considered rare, particularly in sub-Saharan Africa. However, evidence indicates that, today, Africa could have up to 2-3-fold greater rates of stroke incidence and higher stroke prevalence than western Europe and the USA. In Africa, data published within the past decade show that stroke has an annual incidence rate of up to 316 per 100,000, a prevalence of up to 1,460 per 100,000 and a 3-year fatality rate greater than 80%. Moreover, many Africans have a stroke within the fourth to sixth decades of life, with serious implications for the individual, their family and society. This age profile is particularly important as strokes in younger people tend to result in a greater loss of self-worth and socioeconomic productivity than in older individuals. Emerging insights from research into stroke epidemiology, genetics, prevention, care and outcomes offer great prospects for tackling the growing burden of stroke on the continent. In this article, we review the unique profile of stroke in Africa and summarize current knowledge on stroke epidemiology, genetics, prevention, acute care, rehabilitation, outcomes, cost of care and awareness. We also discuss knowledge gaps, emerging priorities and future directions of stroke medicine for the more than 1 billion people who live in Africa.

Comparison of knowledge on stroke for stroke patients and the general population in Burkina Faso: a cross-sectional study

Background

In many parts of Africa, there is limited information on awareness of symptoms of stroke, risk factors for stroke and willingness for stroke prevention, both in the general population and in people with stroke. Knowledge and preventive efforts for stroke in patients with a history of the illness are rarely investigated. This study aims to investigate awareness of stroke symptoms in stroke patients who were admitted to hospitals within 72 hours of a confirmed stroke event in Burkina Faso. This study also aims to investigate preventive behavior for stroke for the general population.

Methods

Face-to-face interviews were conducted with the participants. The sample included 110 first-time stroke patients who had been admitted to one of three tertiary teaching hospitals in Burkina Faso within 72 hours and 750 participants from the general population, who were recruited through clustered sampling. Knowledge of stroke warning signs and current and future efforts on stroke prevention were also assessed.

Results

Only 30.9% of the stroke patients believed that they were at risk before the stroke episode. Obvious warning signs were unfamiliar to both groups. Only 1.3% of the respondents from the general population group knew sudden weakness face arm or leg as a sign of stroke. For all future efforts in stroke prevention, stroke patients demonstrated significantly lower willingness to undertake behavioral changes than the general population. Sixty-six percent and 85% of the stroke patients and the general population, respectively, were willing to take steps to reduce blood pressure.

Conclusion

Public education on stroke warning signs and strategies to increase willingness to engage in preventive behaviors are urgent in African countries. Strategies to improve public awareness for developing countries such as Burkina Faso should be designed differently from that of developed countries to incorporate local beliefs.

Points to consider in cardiovascular disease risk management among patients with rheumatoid arthritis living in South Africa, an unequal middle income country

Background

It is plausible that optimal cardiovascular disease (CVD) risk management differs in patients with rheumatoid arthritis (RA) from low or middle income compared to high income populations. This study aimed at producing evidence-based points to consider for CVD prevention in South African RA patients.

Methods

Five rheumatologists, one cardiologist and one epidemiologist with experience in CVD risk management in RA patients, as well as two patient representatives, two health professionals and one radiologist, one rheumatology fellow and 11 rheumatologists that treat RA patients regularly contributed. Systematic literature searches were performed and the level of evidence was determined according to standard guidelines.

Results

Eighteen points to consider were formulated. These were grouped into 6 categories that comprised overall CVD risk assessment and management (n = 4), and specific interventions aimed at reducing CVD risk including RA control with disease modifying anti-rheumatic drugs, glucocorticoids and non-steroidal anti-inflammatory drugs (n = 3), lipid lowering agents (n = 8), antihypertensive drugs (n = 1), low dose aspirin (n = 1) and lifestyle modification (n = 1). Each point to consider differs partially or completely from recommendations previously reported for CVD risk management in RA patients from high income populations. Currently recommended CVD risk calculators do not reliably identify South African black RA patients with very high-risk atherosclerosis as represented by carotid artery plaque presence on ultrasound.

Conclusions

Our findings indicate that optimal cardiovascular risk management likely differs substantially in RA patients from low or middle income compared to high income populations. There is an urgent need for future multicentre longitudinal studies on CVD risk in black African patients with RA.

Association between white matter hyperintensities and stroke in a West African patient population: Evidence from the Stroke Investigative Research and Educational Network study

BACKGROUND

This study is part of the Stroke Investigative Research and Educational Network (SIREN), the largest study of stroke patients in Africa to date, with computed tomography (CT) or magnetic resonance (MR) imaging data for each patient to confirm stroke. Prior imaging studies performed using high-field MR (≥1.5T) have shown that white matter hyperintensities (WMH), signs of microangiopathy in the subcortical brain, are correlated with many stroke risk factors as well as poor stroke outcomes. The aim of this study was the evaluation of MR images (0.3T-1.5T) from the SIREN study to determine associations between WMH volumes in West African patients and both stroke outcomes and stroke risk factors identified in the SIREN study.

MATERIALS AND METHODS

Brain MR images of 130 Western African stroke patients (age ​= ​57.87 ​± ​14.22) were processed through Lesion Segmentation Toolbox of the Statistical Parametric Mapping software to extract all areas of hyperintensity in the brain. WMH was separated from stroke lesion hyperintensity and WMH volume was computed and summed. A stepwise linear regression and multivariate analysis was performed between patients' WMH volume and sociodemographic and clinical indices.

RESULTS

Multivariate analysis showed that high WMH volume was statistically significantly positively correlated with age (β ​= ​0.44, p ​= ​0.001), waist/hip ratio (β ​= ​0.22, p ​= ​0.03), and platelet count (β ​= ​0.19, p ​= ​0.04) after controlling for head size in a Western African stroke population.

CONCLUSION

Associations between WMH and age and waist/hip ratio previously identified in Western countries were demonstrated for the first time in a resource-limited, homogeneous black African community using low-field MR scanners.