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Stroke occurrence by hypertension treatment status in Ghana and Nigeria: A case-control study
Fred Stephen Sarfo1, Osahon Jeffery Asowata2, Onoja Matthew Akpa3
1Department of Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
Insights
Untreated and uncontrolled hypertension significantly contribute to stroke in Africa. Improving hypertension management is crucial to reduce stroke incidence and its burden in the region.
Area of Science:
- Cardiovascular Epidemiology
- Public Health
- Stroke Research
Background:
- Hypertension is a primary vascular risk factor for stroke.
- Sub-Saharan Africa faces a stroke epidemic due to poor hypertension awareness, detection, treatment, and control.
- Significant gaps exist in managing hypertension across the region.
Purpose of the Study:
- To determine the impact of untreated, treated but uncontrolled, and controlled hypertension on stroke occurrence in Ghana and Nigeria.
- To quantify the attributable risk of different hypertension management statuses to stroke events.
Main Methods:
- A case-control study, the Stroke Investigative Research and Educational Network (SIREN), was conducted across 16 sites in Ghana and Nigeria.
- Acute stroke cases (n=3684) were matched with stroke-free controls (n=3684) by age and sex.
- Associations between hypertension status (untreated, treated uncontrolled, treated controlled) and stroke risk were evaluated using adjusted odds ratios and population-attributable risk.
Main Results:
- Hypertension was significantly more prevalent in stroke cases than controls (p < 0.0001).
- Untreated hypertension (aOR=6.58) and treated but uncontrolled hypertension (aOR=9.95) were strongly associated with increased stroke risk.
- Untreated hypertension accounted for 35.4% and treated but uncontrolled hypertension for 35.9% of the population-attributable risk for stroke.
Conclusions:
- Untreated and inadequately controlled hypertension substantially contribute to stroke incidence in indigenous African populations.
- Targeted interventions addressing hypertension prevention and treatment gaps are essential.
- Collaborative efforts involving communities, healthcare providers, and policymakers can mitigate the rising stroke burden in Africa.
Background:
Hypertension is preeminent among the vascular risk factors for stroke occurrence. The wide gaps in awareness, detection, treatment, and control rates of hypertension are fueling an epidemic of stroke in sub-Saharan Africa.
Purpose:
To quantify the contribution of untreated, treated but uncontrolled, and controlled hypertension to stroke occurrence in Ghana and Nigeria.
Methods:
The Stroke Investigative Research and Educational Network (SIREN) is a case-control study across 16 study sites in Ghana and Nigeria. Cases were acute stroke (n = 3684) with age- and sex-matched stroke-free controls (n = 3684). We evaluated the associations of untreated hypertension, treated but uncontrolled hypertension, and controlled hypertension at BP of <140/90 mmHg with risk of stroke occurrence. We assessed the adjusted odds ratio and population-attributable risk of hypertension treatment control status associated with stroke occurrence.
Results:
The frequencies of no hypertension, untreated hypertension, treated but uncontrolled hypertension and controlled hypertension among stroke cases were 4.0%, 47.7%, 37.1%, and 9.2% vs 40.7%, 34.9%, 15.9%, and 7.7% respectively among stroke-free controls, p < 0.0001. The aOR and PAR (95% CI) for untreated hypertension were 6.58 (5.15-8.41) and 35.4% (33.4-37.4); treated but uncontrolled hypertension was 9.95 (7.60-13.02) and 35.9% (34.2-37.5); and controlled hypertension 5.37 (3.90-7.41) and 8.5% (7.6-9.5) respectively. Untreated hypertension contributed a PAR of 47.5% to the occurrence of intracerebral hemorrhage vs 29.5% for ischemic stroke. The aOR of untreated hypertension for stroke occurrence was 13.31 (7.64-23.19) for <50 years; 7.14 (4.51-11.31) for 50-64 years; and 3.48 (2.28-5.30) for 65 years or more.
Conclusion:
The contribution of untreated hypertension and treated but uncontrolled hypertension to stroke occurrence among indigenous Africans is substantial. Implementing targeted interventions that address gaps in hypertension prevention and treatment, involving the local population, healthcare providers, and policymakers, can potentially substantially reduce the escalating burden of strokes in Africa.
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