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AFRICA
S7
CVJAFRICA • Volume 26, No 2, H3Africa Supplement, March/April 2015
leading cause of death throughout most of the last century. In
the United States, for example, heart disease has been the leading
cause of death every year since 1918.
2
Currently, however,
most CVD deaths occur in low- and middle-income countries
(LMIC) and there is growing concern that an epidemic of CVDs
is emerging in these countries that must be prevented.
3,4
The
World Health Organisation (WHO) and the United Nations
have also called attention to a rising burden of CVD and other
non-communicable diseases and the need for aggressive measures
to forestall this epidemic in these countries
5,6
In sub-Saharan Africa (SSA), where all countries are part
of the developing world, the magnitude of and trends in CVD
deaths remain incompletely understood. The African regional
office of the WHO has stated that CVDs are ‘increasing rapidly
in Africa, and it is now a public health problem throughout the
African region’.
7
However, a systematic analysis of estimates for
CVD mortality in the Global Burden of Disease (GBD) 2010
study showed no significant rise in age-standardised mortality
rates for CVD in SSA for the period of 1990–2010.
8,9
Similarly,
recent data from the INDEPTH Health and Demographic
Surveillance System show little evidence of NCD mortality rates
increasing over time.
10,11
However, data on CVDs are limited in
the region,
12-14
and novel methods are required in order to make
meaningful estimates.
Clarifying the epidemiology of CVD in SSA is essential
for the formulation of regional and national health policies.
Accordingly, we explored as a primary objective, estimates of the
number of deaths, age-standardised and age- and gender-specific
mortality rates, and their trends in SSA, by age and gender, for
the period 1990–2013 for total CVD, rheumatic heart disease
(RHD), ischaemic heart disease (IHD), cerebrovascular disease
(including ischaemic and haemorrhagic stroke), hypertensive
heart disease, cardiomyopathy and myocarditis, atrial fibrillation
and flutter, aortic aneurysm, peripheral arterial disease (PAD)
and endocarditis. These data for SSA were also compared to data
for developing and developed countries.
Methods
Age and gender year-specific mortality rates for CVD were
estimated using the methods as published in the GBD 2013
study.
1
In brief, the GBD 2013 study collected all available data
on mortality, including vital registration and verbal autopsy.
Raw data were corrected to account for outliers and non-specific
causes of death (i.e. ‘garbage’ codes).
Modelling was performed using a custom ensemble-model
approach (CODem) to estimate deaths for each country,
including countries without data.
15
CODem employs Gaussian
process regression and spatio-temporal modelling, as well as
cardiovascular-specific covariates, such as systolic blood pressure,
to produce consistent estimates.
1
Estimates were adjusted to
fit an envelope of all-cause mortality and all-cardiovascular
mortality to ensure that no strata contained more deaths that
occurred for any of its parent categories.
For SSA, mortality data for the years 1980–2011 were
used from Madagascar, Ethiopia, Mauritius, Seychelles, South
Africa, Zambia, Mozambique, Kenya, Tanzania, Burkino Faso,
Zimbabwe, Mali and Ghana. For all quantities reported, 95%
uncertainty intervals (UIs) were also computed using 1 000
draws from the posterior distribution of each age–gender–
country–year-specific set of estimates. Death numbers from each
country and each cause were summed to produce estimates for
the entire region of SSA.
Results
As shown in Table 1, CVDs caused nearly one million deaths
in SSA in 2013. The number of deaths in women (512 269)
exceeded those in men (445 445) for total CVDs and also for all
cardiovascular causes of death except ischaemic heart disease,
aortic aneurysms and peripheral vascular disease. There were
more deaths from stroke (409 840) than ischaemic heart disease
(258 939). Compared to 1990, CVD deaths increased 81% in
2013. Similarly, deaths for all component CVDs also increased,
ranging from a 7% increase in rheumatic heart disease to a 196%
increase in atrial fibrillation. The age-standardised mortality rate
(per 100 000) for total CVD in 1990 was 327.6 (CI: 306.2–351.7)
and 330.2 (CI: 312.9–360.0) in 2013, representing a 1% increase.
As previously demonstrated, SSA experiences the world’s
lowest IHD death rates, and IHD ranks below stroke as a leading
cause of CVD death in the region.
12
On average, SSA experienced
no significant change in age-standardised IHD mortality rate
Table 1.Total number of deaths and age-standardised mortality rates for component cardiovascular causes of death
in 1990 and 2013 and the respective percentage changes
Cause
Number
of
deaths,
1990
95% UI
Number
of
deaths,
2013
95% Ul
%
Change
Age-standard-
ized death rate
(per 100 000),
1990
95% UI
Age-standard-
ized death rate
(per 100 000),
1990
95%UI
%
Change
Ischaemic heart disease
138 308 (116 618–153 645) 258 939 (232 158–305 680)
87
91.4 (76.9–101.7)
92.9 (82.8–110.2)
2
Ischaemic stroke
101 040 (77 903–117 660) 206 439 (139 860–242 225)
104
75.0 (57.2–87.5)
81.5 (55.0–95.7)
9
Hemorrhagic stroke
125 603 (103 055–147 517) 203 401 (173 620–262 418)
62
72.2 (57.1–87.6)
64.7 (54.0–87.5)
–10
Hypertensive heart disease
37 525 (29 485–49 443)
86 035 (62 970–111 978)
129
26.8 (21.0–36.5)
32.8 (24.2–44.0)
22
Cardiomyopathy
28 917 (23 557–36 082)
53 742 (44 926–65 634)
86
12.7 (10.6–17.0)
14.5 (11.9–18.2)
14
Rheumatic heart disease
23 625 (17 644–31 608)
25 239 (20 478–40 444)
7
10.3
(7.5–13.7)
6.5 (5.3–10.1)
–37
Atrial fibrillation
414 (331–509)
1 227 (959–1 558)
196
0.4
(0.3–0.5)
0.6 (0.5–0.8)
50
Aortic aneurysm
5 150 (3 370–6 714)
9 854 (7 809–12 840)
91
3.3
(2.2–4.3)
3.4 (2.7–4.5)
3
Peripheral vascular disease
469 (371–580)
1 338 (1 122–1 618)
185
0.4
(0.3–0.5)
0.6 (0.5–0.7)
50
Endocarditis
9 622 (6 339–15 825)
13 868 (10 967–18 524)
44
4.7
(3.0–8.6)
3.7 (2.9–5.3)
–21
Other cardiovascular diseases 59 206 (48 291–74 859)
98 632 (77 904–138 971)
67
30.3 (24.8–41.1)
29.1 (22.7–42.8)
–4
Total cardiovascular diseases 529 880 (492 351–568 410) 958 713 (909 427–1 049 606)
81
327.6 (306.2–351.7)
330.2 (312.9–360.0)
1