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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 2, March/April 2018
AFRICA
71
A test of conditional independence (Cochran’s Mantel–
Haenszel chi-squared) gave
χ
2
1
=
0.314;
p
=
0.575, indicating
that ischaemic stroke was conditionally independent of gender
after adjusting for age. No significant association was observed
therefore between ischaemic stroke and gender across the various
age groups.
Discussion
There is scanty information on the extent and nature of stroke
in Kenyan public hospitals. This study was set to determine
the clinico-epidemiological profile of stroke in Kenya’s leading
public health tertiary institutions.
Higher incidence of ischaemic stroke was observed, with
hypertension, tobacco use and diabetes as the most common
vascular risk factors. These findings agree with those previously
reported from Nairobi and Aga Khan private hospitals, where
ischaemic stroke was the most common stroke sub-type, and
hypertension and diabetes were the leading risk factors.
11,12
An
important observation in this study was the distribution of
stroke and the associated risk factors in both rural (MTRH)
and urban (KNH) regions. This signifies a general shift in
lifestyle and demographics, which often accompanies economies
in transition, and it is perhaps best substantiated by cigarette
smoking as the second most-common risk factor.
Advancing age is the most important predictor of
cardiovascular morbidity and mortality. The increased stroke
cases observed with increasing age in this study attest to that.
13
The stroke burden was higher in the 40–79-year age bracket,
which represents middle-aged adults, whom as has been stated
before, contribute to the 78% stroke burden in low- and middle-
income countries.
14
It has also been shown that high and
increasing rates of stroke affect people at much younger ages
in sub-Saharan Africa, resulting in greater numbers of years
of potential life lost.
15,16
Hence, aggressive efforts in improving
cardiovascular health, promoting healthy aging, preventing
cardiovascular risk factors and fast-tracking proven intervention
strategies are necessary to halt and reverse the CVD burden.
13,17
The post-stroke mortality rate in the current study was
higher than the average national estimate of 12% for CVD
deaths in hospitals, suggesting poor outcomes in post-stroke
events. Similar high fatalities have been observed elsewhere in
Africa, with high blood pressure predicting fatality in the short
term, particularly with haemorrhagic stroke.
18
In-patient stroke
mortality rate of 19.3% has also been reported in the Congo,
33.3% in Tanzania, 43.2% in Ghana and 23.2% in Cameroon by
day 30.
18-21
Monthly stroke mortality rates in South Africa are
similarly high, with 23% mortality rate reported at month 6.
22,23
Therefore continuous monitoring of stroke incidence,
outcomes and determinants should be enhanced to provide the
much-needed information for guiding health service provision
and allocation of resources. More work is required to assess the
impact of actual care patterns on stroke prognosis over time,
while prioritising the reduction of haemorrhagic stroke in Kenya
and sub-Saharan Africa as a whole.
24,25
Hypertension is the single most important risk factor and
contributor to disability and premature death. In our study,
the burden of hypertension was equally distributed across
gender. This confirms previous findings from sub-Saharan
Africa that show hypertension as the most powerful predictor
of stroke. The contribution of untreated hypertension to stroke
burden has been demonstrated in Ethiopia and Tanzania,
26,27
and
reiterates the importance of understanding the primary drivers
for effective prevention.
15,28,29
Treatment of hypertension can reduce the risk of stroke
by more than 40%. There is a need therefore to develop
comprehensive risk-reduction strategies to mitigate the social and
economic burden of stroke. Renewed emphasis on prevention
and control of high blood pressure is necessary.
16,30
Non-communicable diseases are beginning to feature on
the public health agenda in developing countries.
31,32
However,
despite CVD being the second leading cause of morbidity and
mortality in Kenya, its prevention and mitigation of risk factors
are yet to receive the warranted attention necessary to protect
and improve public health. There is a need to build scientific
evidence that will assist in health planning, advocacy and policy
making. The Kenyan county governments should deliberately
invest in capacity building and harnessing of resources for CVD
research and service provision. Supporting the development and
sustenance of CVD surveillance systems will enhance knowledge
generation and utilisation of evidence in fast-tracking prevention
and control measures.
Conclusions
Ischaemic stroke was the most prevalent stroke at 55.6%.
Hypertension was the commonest risk factor, followed by
smoking and diabetes, and the overall mortality rate was higher
than that estimated by the WHO. Variation in stroke occurrence
was observed based on gender and increasing age. There is a
need to implement and/or scale up proven interventions geared
towards preventing and controlling stroke and the associated
risk factors, while being cognisant of the socio-demographic
and cultural changes accompanying economies in transition.
In addition, raising the population’s awareness of lifestyle
factors likely to predispose them to stroke, and investing in care,
management and surveillance systems may, with time, reduce the
number of cases of stroke, initial stroke severity and improve
public health.
This research was supported by an NIH grant (D43 TW009333) from Fogarty
International Centre for the ‘Cancer and Tobacco Control Training and
Research across the Lifespan in Kenya’
project spearheaded by Prof Scot C
Remick of Mary Babb Randolph Cancer Centre, West Virginia University. We
thank the director of the Kenya Medical Research Institute, and the KNH
and MTRH review boards for granting permission and providing an enabling
environment to undertake this study. Many thanks to Doreen Njeri and Ayub
Alembi of Nairobi, and Henry Mwangi and Meinard Shikhang’a of MTRH,
and the KNH and MTRH medical fraternity for their continued support.
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World Health Organisation. Global status report on non-communicable
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Ogeng’o JA, Gatonga P, Olabu BO. Cardiovascular causes of death in