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AFRICA
CVJAFRICA • Volume 26, No 2, H3Africa Supplement, March/April 2015
The age-standardised incidence of stroke in Tanzania was similar
to the rates in China where the age-standardised incidence of
first-ever stroke per 100 000 person years increased rapidly
from 124.5 in 1992–1998 to 190.0 in 1999–2005, and to 318.2 in
2006–2012.
27
Unfortunately, no rigorously conducted stroke-incidence
study has been performed twice in the same location to provide
secular trend data on the incidence ‘velocity’ (trend) of stroke in
Africa. Using the GBD data (Fig. 2), increase in age-standardised
ischaemic stroke incidence from 1990 to 2010 ranged between
5.2% (South Africa) and 27.8% (DRC, Table 3).
Overall, in Africa, there was significant (
p
<
0.001) mean
increase in age-standardised ischaemic stroke incidence of
14.8% (
±
4.1%) between 1990 and 2010. Similarly (Fig. 2),
increase in age-standardised haemorrhagic stroke incidence from
1990 to 2010 ranged between 13.0% (the Gambia) and 45.7%
(Burundi, Table 3). Overall, in Africa, there was significant (
p
<
0.001) mean increase in age-standardised haemorrhagic stroke
incidence of 28.7% (
±
11.1%) between 1990 and 2010. Therefore,
the incidence of stroke in Africa is not only among the highest in
the world, the incidence velocity is also very high.
Urbanisation and other socio-demographic and lifestyle
changes in Africa, as in other parts of the developing world, are
increasing rapidly, and the results from this study suggest that, in
the absence of effective preventive measures, this is likely to lead
to further substantial increases in stroke incidence.
Prevalence
A retrospective chart review of clinically and CT-diagnosed
stroke patients evaluated between January 2000 and March 2005
in Tikur Anbessa tertiary referral and teaching hospital (Addis
Ababa, Ethiopia) showed that stroke accounted for 5% of all
head CT indications done in Ethiopia.
33
A prevalence rate could
not be calculated in the absence of the number in the referral base.
Community-based studies constitute the best way to
determine the true prevalence of stroke, although they are very
rare in Africa due to lack of manpower and research funds.
Estimating the prevalence of stroke survivors in the community
is complicated by the difficulty in making a retrospective and
yet accurate diagnosis of stroke and stroke type months or
years after the event.
16
Estimations are also biased by under-
representation of fatal cases.
16
Therefore, prevalence, which
depends on incidence and case fatality, is better estimated from
incidence studies of first-ever stroke and survival. However in
sub-Saharan Africa, incidence studies are very rare and difficult
to conduct.
16
Algeria
Benin
Botswana
Burkina Faso
Burundi
Central African
Republic
Chad
Congo
Côte d’Ivoire
Democratic
Republic of Congo
Egypt
Equatorial Guinea
Ethiopia
Ghana
Guinea
Guinea-Bissau
Kenya
Lesotho
Liberia
Libya
Madagascar
Malawi
Mali
Mauritania
Mauritius
Morocco
Mozambique
Namibia
Niger
Nigeria
Rwanda
São Tomé
and Príncipe
Senegal
Sierra Leone
Somalia
South Africa
Sudan
Swaziland
The Gambia
Togo
Uganda
Zambia
Zimbabwe
0 10 20 30 40 50 60 70
% Change in Incidence
Country
Haemorrhagic stroke
Ischaemic stroke
Fig. 2.
Model-derived percentage changes in ischaemic and
haemorrhagic stroke incidence in African countries
between 1990 and 2020.
Table 3. Estimates of average percentage change over 1990 to 2010 in age-adjusted incidence, mortality and DALYs of stroke in Africa
Rates per 100 000 person years
1990
(mean, SD)
2010
(mean, SD)
Min.
change*
(%)
Country with min.
change
Max.
change*
(%)
Country with max.
change
Mean/
median
change**
(%) SD
p-
value
Age-standardised incidence ischaemic 129.4, 15.1 148.4, 16.3
5.18 South Africa
27.8
Democratic
Republic of Congo
+14.8 4.05
<
0.001
Age-standardised incidence haemor-
rhagic
58.9, 11.0
75.2,12.9
13.0
The Gambia
45.7
Burundi
+28.7 11.1
<
0.001
Age-standardised mortality ischaemic
53.3, 15.2 48.1, 12.5 –45.5
Mauritius
95.0
Burkina Faso
–7.5**
0.001
Age-standardised mortality haemor-
rhagic
69.2, 20.1 58.8, 16.9 –52.2 Equatorial Guinea 67.9
Burkina Faso –12.7**
<
0.001
DALYs lost ischaemic
853.8, 231.7 756.1, 192.7 –53.1
Mauritius
79.0
Burkina Faso –10.3**
<
0.001
DALYs lost haemorrhagic
1574.7, 451.1 1287.1, 383.9 –57.4 Equatorial Guinea 51.6
Zimbabwe
–18.9**
<
0.01
*Countries with the minimum and maximum changes in rates are depicted. **Median percentage change.