Dr. Edward Ddumba, the Medical Director of St. Francis Hospital Nsambya (middle) with part of the Stroke Study team
A systematic review conducted as part of a study to assess the risk factors for haemorrhagic (HS) and ischemic stroke (IS) in Sub-Saharan Africa (SSA) - The Stroke Study, has suggested that HIV is a risk factor for all stroke, although it is more prevalent among those with IS rather than HS. A similar finding was observed in a study from Malawi and Tanzania where the overall prevalence of HIV infection among patients presenting with stroke was 20.9%. It is well recognized that both HIV infection and antiretroviral therapy (ART) could potentially increase an individual’s risk of stroke.
Funded by the MRC (UK), the study, “haemorrhagic and ischemic stroke in urban Uganda: risk factors, outcomes, caregiver burden and experiences”, is being conducted in Uganda’s St. Francis Hospital Nsambya by a team of researchers from MRC/UVRI and LSHTM Uganda Research Unit.
It is a compilation of four sub-studies; sub-study I is a systematic review to obtain information on risk factors for haemorrhagic and ischemic stroke in Sub-Saharan Africa while sub-study II is a hospital based case control study to obtain baseline information on risk factors for haemorrhagic and ischemic stroke. Sub-study III is a prospective cohort study to obtain information on outcomes and associated factors for haemorrhagic and ischemic stroke and sub- study IV is a descriptive cross sectional study to obtain information on caregiver burden and experiences among caregivers attending to stroke patients.
Worldwide, stroke is a leading cause of death and of chronic disability. It is estimated that 15 million people suffer a stroke annually; of these, five million die and another five million are left permanently disabled, placing a burden on family and community. Approximately 85% of deaths occur in low and middle income countries. In SSA stroke represents an important part of the chronic disease burden, but there are relatively few data on stroke risk factors and its outcomes.
Although the risk factors for HS and IS appear to vary considerably between countries, hypertension remains the most important stroke risk factor globally and populations in SSA appear to be more at-risk of developing hypertension and subsequent stroke compared to the western world. This difference could be accounted for by a combination of factors, including inadequate funding and lack of infrastructure, which often impair diagnosis, screening, treatment and control of hypertension in SSA. According to the systematic review, several non-modifiable risk factors for stroke, such as age, gender, race, ethnicity, and heredity; and potentially modifiable risk factors such as hypertension, atrial fibrillation (irregular heart beat) (AF), hyperlipidemia, Diabetes Mellitus, cigarette smoking, physical inactivity, and transient ischemic attack (TIA) were identified in SSA. The INTERSTROKE study demonstrated the commonality of the main risk factors for stroke in SSA: hypertension (37%), alcohol intake (11%), physical inactivity (12%), and Diabetes Mellitus (12%).
Of the12 studies reviewed as part of this work out of 562 that were identified from different online repositories, there were only five case-control studies from SSA that reported information on risk factors for all stroke. Only one study reported data on IS and HS risk factors separately. Furthermore, the vast majority of cases were identified in hospital and so are unlikely to be representative of the totality of stroke cases in the community.
Speaking at a meeting at the end of the study, Dr. Edward Ddumba, the Medical Director of St. Francis Hospital commended the MRC/UVRI and LSHTM Uganda Research Unit for initiating the study as it would provide local data that would improve care and management of stroke patients. “Most of the available data on stroke are from the western world, where for example patients are generally older and of different socio- economic backgrounds, compared to those we are seeing in Uganda. “ “This work will help us to understand stroke in the local context and therefore improve patient management and make healthcare in Uganda more affordable”, he added.
According to Dr. Gertrude Namale, the Principal Investigator of the study, “In Uganda, stroke is one of the top five causes of adult death, largely due to the high prevalence of modifiable risk factors such as hypertension. It accounts for 3.7% of all admissions in Uganda’s hospitals”.
She however noted that data on risk factors and outcomes for haemorrhagic and ischemic stroke in urban Ugandan are limited. “Up-to-date data are required to estimate the current impact of stroke in Uganda and the required resources to meet this increasing disease burden”.
Poor control of risk factors, especially hypertension, may contribute to the rising stroke burden. In Uganda, hypertension is more prevalent in urban (25.5%) than in rural (24.4%) areas. It is hoped that this work will inform policy makers and scale up routine screening for and treatment of cardiovascular risk factors for stroke in Uganda.
Ischemic stroke occurs as a result of an obstruction within a blood vessel supplying blood to the brain while hemorrhagic stroke results when a blood vessel in the brain ruptures or breaks, spilling blood into the surrounding tissues.