Describe stroke epidemiology in Zambia including stroke subtype (ischemic vs. hemorrhagic), risk factors, and in-hospital mortality.

While stroke burden has remained constant in high-income countries, it has significantly increased in low- and middle-income countries including those in sub-Saharan Africa (SSA). However, systematic studies of stroke epidemiology and outcomes in SSA are lacking.

Standardized data collection instruments were used to prospectively collect pertinent patient demographic, clinical, laboratory and imaging results as well as in-hospital mortality for consecutive stroke patients admitted to the University Teaching Hospital in Lusaka, Zambia between October 2018 – April 2019. Strokes were classified as ischemic stroke (IS) or hemorrhagic stroke (HS) based on CT appearance.  Patients who did not have neuroimaging were classified as unknown stroke (US).  Descriptive statistics were calculated and compared between ischemic and hemorrhagic stroke using t-tests for continuous variables and chi-square analyses for categorical variables.

320 stroke patients were enrolled with an average age of 60 (SD 18) years and 62% (n=201) female. Stroke subtypes were 48% IS, 27% HS, 25% US.  Compared to other subtypes, patients with IS were significantly more likely to be female (p=0.006), and those with HS were significantly younger (p=0.006). Stroke risk factors included: hypertension (73%), heart disease (21%), HIV infection (17%), hyperlipidemia (17%), diabetes (11%), and atrial fibrillation (9%).  Diabetes (p=0.01), heart disease (p=0.09), and atrial fibrillation (p=0.001) were significantly more prevalent in IS. In-hospital mortality for all strokes was 22% and was significantly higher in HS (28%, p=0.03). 

This Zambian stroke cohort is notable for their young age, extremely high rate of hypertension, and over-representation of HIV infection (national prevalence: 12%).  Our results reflect the growing burden of stroke in Zambia, the significant role of HIV infection, and the need to improve hypertension diagnosis and treatment for primary stroke prevention.