WSO - July 2023 - 635

Okekunle et al.
635
Introduction
Stroke is a principal cause of disability and mortality worldwide,1-3
with significant increases in epidemiological burden
in low- and middle-income countries (LMICs).4-6
Recent evidence suggests a rapidly growing burden of
stroke in Africa with an annual age-adjusted incidence as
high as 316 per 100,000 persons, an age-adjusted prevalence
of up to 1460 per 100,000 persons, and a 3-year fatality
rate of up to 84%.5 Also, stroke and stroke-related
disability accounted for 70% and 80% of all mortality in
LMICs between 1970 and 2020.5
The case for the high burden of stroke in Africa is
mounting, but large geographical regions of the continent
are without high-quality incidence and case-fatality data.
Also, the quality of earlier systematic reviews7-9 has been
limited by the high heterogeneity across studies and deficiencies
in standardized methods of evaluating stroke epidemiology.
Many studies on stroke epidemiology among
Africans were characterized by low statistical power and
poor generalizability across the hugely diverse African
population. There are several stroke prevalence studies
among Africans. However, they do not provide a clear picture
of the African stroke landscape and have limited policy
implications and priority settings related to interventions
for stroke prevention, surveillance, acute care and rehabilitation
among Africans.6 Therefore, an estimate of the burden
of stroke using high-quality stroke incidence studies in
Africa is important, in the light of newer studies, to advance
the understanding of stroke science and care in Africa.
Thus, we pooled data from high-quality epidemiological
stroke studies to determine the true stroke incidence and
30-day case-fatality rates (CFRs) among Africans.
Methods
This systematic review and meta-analysis were conducted in
accordance with the MOOSE (Meta-analysis of Observational
Studies in Epidemiology) guidelines10 and reported using the
Preferred Reporting Items for Systematic Review and MetaAnalyses
(PRISMA) framework.11 The protocol was prospectively
registered in PROSPERO.12
Search strategy and study selection
The search strategy used " stroke " terms from the Cochrane
Stroke Strategy 202013 and an adapted filter14 to search for
previously published reports on the epidemiology of stroke
among indigenous Africans in MEDLINE (OVID),
EMBASE (OVID), AJOL, EBSCO, Google Scholar,
Cochrane Library, IMSEAR via Global Index Medicus,
Science Citation Index Expanded (SCI-EXPANDED),
Social Sciences Citation Index, and Arts & Humanities
Citation Index within ISI Web of Science (from the earliest
possible record to January 2022). Reference lists of
retrieved studies were reviewed for additional studies.
Inclusion criteria
Studies were eligible based on the following criteria: population
boundaries defined within Africa, prospective and consecutive
recruitment, pre-specified sampling plan, complete
community-based case-ascertainment of stroke (with
multiple overlapping sources) or non-community-based caseascertainment
(acute hospital-based registry, rehabilitationbased
registry), including case series and case-control studies.
Studies were included if stroke was confirmed based on a
predefined set of criteria, for example, World Health
Organization (WHO),15
imaging, where possible),
or clinical criteria (confirmed by
including
cerebral
infarction,
intracerebral hemorrhage, subarachnoid hemorrhage, or
uncertain pathological subtypes with no restrictions on age,
sex, degree of impairment post-stroke, or interventions.
Exclusion criteria
Studies were excluded if they were case studies, randomized
controlled trials, reviews, epidemiological reports
from mixed populations (e.g. stroke and head injury) without
specific results for the stroke population, cross-sectional
or retrospective recruitment, qualitative assessment
only, or adopted convenience sampling. All references were
collated using EndNote,16 and duplicates were removed
using the EndNote automated function and then manually.
Data collection and analysis
Three independent reviewers (A.P.O., O.A., and S.J.)
screened the title or abstract of all citations, two reviewers
(S.J. and R.A.) were randomly assigned to evaluate the
selected citations, and disagreements were resolved by
recourse to a third reviewer (M.H., C.W., and M.O.) to
reach a consensus. The article with the most comprehensive
dataset was selected when there were multiple articles from
the same study population with evidence of overlapping
data or identical participant characteristics. The search
strategy and selection procedure are detailed in Figure 1.
Data extraction, selection, and coding
Data extraction was carried out independently by two
reviewers (A.P.O. and O.A.) using a previously designed
proforma,15 verified by another reviewer (S.J.). The
difference(s) was resolved in an organized discussion in the
review team. Extracted data included author, year, study
name, sample characteristics (country, city, study period,
and design), and epidemiological data (number of stroke
cases and subtype, age, crude incidence, 1-month CFR).
Assessment of risk of methodological bias
The Newcastle-Ottawa scale was used to determine the
risk of bias (see Supplementary Table 1).
International Journal of Stroke, 18(6)
WSO - July 2023

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