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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 colleagues

62

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

http://infobase.who.int

; WHO Statistical

Information System

http://www.who.int/whosis

; Mackay J, Mensah GA. The

atlas of heart disease and stroke. Geneva: World Health Organization. 2004.

http://www.who.int/cardiovascular_diseases/resources/atlas/en.

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