The SA Journal Diabetes & Vascular Disease Vol 13 No 2 (December 2016)

44 / 52

94 VOLUME 13 NUMBER 2 • DECEMBER 2016
REVIEW SA JOURNAL OF DIABETES & VASCULAR DISEASE
code in 555 stroke patients, 72% of whom had cerebral infarctions
confirmed on computed tomography. Ninety-three of the 555
patients (16.8%) had evidence of coronary artery disease, of whom
81 had features of myocardial ischaemia, eight had pathological Q
waves and four patients had features of acute myocardial infarction.
There has been longstanding controversy regarding ECG diagnosis
of myocardial ischaemia in black Africans.53-57
Ignoring ECG features of ‘ischaemia’ and ascribing such changes
to ‘normal variation’ poses the potential danger of under-diagnosis
or misdiagnosis of myocardial ischaemia in black Africans. Rather,
future work should attempt to unravel the genetic mechanisms
behind abnormal ECG patterns in black Africans.
The combination of clinical assessment, chest radiograph,
resting electrocardiography, transthoracic echocardiography and
MUGA scanning showed features of CHD in 18 patients (17.6%)
in the MEDUNSA study. Scintigraphy with or without dipyridamole
infusion in 60 stroke patients in this study revealed features of
coronary heart disease in 45% of the patients. Macroscopic and
microscopic pathological examinations of the heart and coronary
arteries for evidence of infarction in 23 stroke patients in the study
revealed the highest rate of myocardial infarction (17.4%).
Observed differential mortality rates in different ethnic groups in
multiracial African communities such as South Africans have been
at least partly ascribed to different stages of the epidemiological
transition. For instance, Norman and colleagues58 found that black
Africans had approximately 60, 70 and 82% less CHD mortality
rates compared to South African Coloureds, whites and Asians,
respectively.
Part of the reason for relatively high IHD mortality rates in
South African Asians is due to their high prevalence of diabetes
mellitus.59-61 By contrast, mortality from stroke in black Africans
exceeds the rates for Coloureds, whites and Asians by 2, 96 and
19%, respectively. However, mortality from hypertensive heart
disease in black South Africans was 2.5, nine and three times higher
than rates in Coloureds, whites and Asians, respectively.
Bradshaw and colleagues62 demonstrated that IHD was the
leading cause of death among 71 641 South African men over
60 years, while it was the second most common cause of death
among the top causes of deaths in 73 474 women in the year 2000
(Table 5). In South African men aged 15 to 45 years in the same
study, IHD was ninth among the top 10 causes of death (1.1%),
although it did not feature among the top 10 causes of death
in women. HIV/AIDS was the predominant cause of mortality in
younger age groups, accounting for 40.7% of deaths in men and
64.4% in women.
In 2005, the WHO estimated 188 000 and 173 000 deaths
from IHD in men and women, respectively in SSA.63 These age-
standardised mortality rates (ASMR) will rise by 27 and 25% in men
and women, respectively by the year 2015, and by 70 and 74%,
respectively by the year 2030.
Table 6 represents ASMR from IHD in selected countries from
the main regions of SSA. Despite higher ASMR in men in mainland
Africa, rates in females were close to those in men (Table 6). In
Seychelles, ASMR in men was three-fold higher than rates in
women, while Mauritius shows the highest ASMR for IHD in both
genders, with a male preponderance.
Some caveats against current and future projections of mortality
data for IHD in SSA include the use of approximations that often
embrace substantial uncertainties, especially in the estimation of
cause-specific deaths. This huge degree of uncertainty has been
attributed to a meagre database on IHD as a specific cause of death
in Africa and to the overall low coverage of vital registration.
Despite the heavy toll inflicted by HIV/AIDS in SSA, comparative
ASMR across the continent indicate that mortality from IHD matches
Table 6. Age-standardised mortality rates for ischaemic heart disease in
the WHO Africa region, by selected countries and gender, 2002.
Region/country
Estimated population
(millions)
Age-standardised mortality
rates for IHD (per 100 000)
Males Females
DR Congo = Democratic Republic of Congo, UR Tanzania = United Republic
of Tanzania.
Eastern Africa
Uganda
Tanzania
Ethiopia
25.00
36.28
6.90
150
147
149
120
128
127
Central Africa
DR Congo
Rwanda
Malawi
51.20
8.27
11.87
166
149
152
132
122
125
Southern Africa
Botswana
South Africa
Mozambique
1.77
44.76
18.54
142
159
124
102
99
107
Western Africa
Nigeria
Ghana
Cameroon
120.91
20.47
15.73
160
143
154
127
114
124
Islands
Mauritius
Seychelles
1.21
0.80
277
151
161
49
Table 7. Comparison of age-standardised mortality rates for ischaemic
heart disease and HIV/AIDS in the WHO Africa region in selected
countries in 2002.
DR Congo = Democratic Republic of Congo, UR Tanzania = United Republic of
Tanzania, ASMR = age-standardised mortality rates.
Sources: WHO Global InfoBase ; WHO Statistical
Information System ; Mackay J, Mensah GA. The
atlas of heart disease and stroke. Geneva: World Health Organization. 2004.
Region/country
Estimated
population
(millions)
ASMR (per 100 000) ASMR
IHD HIV/AIDS
HIV/AIDS:
IHD ratio
Eastern Africa
Uganda
UR Tanzania
25.00
36.28
270
275
555.6
593.2
2.06
2.16
Central Africa
DR Congo
Malawi
51.20
8.27
298
271
277.7
345.4
0.93
1.27
Western Africa
Nigeria
Ghana
120.91
20.47
287
257
316.8
174.6
1.10
0.66
Southern Africa
Botswana
South Africa
1.77
44.76
244
258
2,243.1
840.3
9.19
3.26
Islands
Mauritius
Seychelles
1.21
0.80
438
200
1.6
5.5
0.004
0.03