23 / 74
CARDIOVASCULAR JOURNAL OF AFRICA • Volume 30, No 2, March/April 2019
AFRICA
89
Dyslipidaemia was defined as having a history of lipid-
lowering therapy or low-density lipoprotein (LDL) cholesterol
>
70 mg/dl (
>
1.81 mmol/l).
10
Atherogenic dyslipidaemia was defined
as having elevated serum triglycerides (
≥
150 mg/dl; 1.7 mmol/l)
combined with low high-density lipoprotein (HDL) cholesterol
(
<
40 mg/dl;
<
1.04 mmol/l).
11
Isolated atherogenic dyslipidaemia
was defined as having atherogenic dyslipidaemia without standard
dyslipidaemia. Hypertension was defined as having a history of
hypertension or systolic/diastolic blood pressure
≥
140/90 mmHg.
Diabetes (type 1 or 2) were defined as a history of diabetes or
fasting plasma glucose
>
126 mg/dl (
>
6.99 mmol/l).
Body weight and height were measured to the nearest 0.5 kg
and 0.5 cm, respectively. Weight was determined using a standard
scale with the subjects barefoot and wearing light clothes. Height
was measured using a wall-mounted stadiometer. Body mass index
(BMI) was calculated as weight (kg)/height squared (m
2
). Patients
were considered overweight or obese if they had a BMI of 25–29.9
or
≥
30 kg/m
2
, respectively. Waist circumference was measured with
a non-stretchable measuring tape at the level of the umbilicus.
Central obesity was defined as a waist-to-height ratio
≥
0.5.
12
Blood samples were collected and analysed in the accredited
controlled laboratory units of the participating centres. Routine
assays were used for analysis of glycated haemoglobin (HbA
1c
)
and serum glucose and lipid levels.
Statistical analysis
Continuous data are reported as median (5th, 95th percentile);
categorical data are reported as percentages. The Mann–Whitney
U-
test was used for comparison of continuous variables, whereas
the Pearson
χ
2
test was used for categorical variables. All analyses
were two-tailed, and
p-
values
<
0.05 were considered significant.
Analysis was done using PASW statistics for Mac (23.0; SPSS
Inc, Chicago, IL, USA). GraphPad Prism for Mac was used for
the generation of figures.
Results
The study population comprised 1 681 subjects, of whom 425
(25%) were women (Table 1). The median age was 56 years in
men and 61 years in women (
p
<
0.001). Premature ACS was
highly prevalent, in 46% of men aged less than 55 years and in
67% of women aged
<
65 years. Education status was higher in
men, with only 7 and 17% reporting no education and having
completed primary school only, respectively, compared to 26 and
25% of women (
p
<
0.001).
A larger proportion of men presented with STEMI (49%),
while other presentations (unstable angina and NSTEMI) were
more frequent in women (32% each;
p
<
0.001; Table 1). An
atypical presentation with absence of chest pain was more
frequent in women (7 vs 4% of men;
p
=
0.003), and dyspnoea as
a presenting symptom was more prevalent in women (58 vs 48%
in men,
p
<
0.001). Approximately one-fifth of subjects had had
a prior attack or myocardial infarction.
Median BMI was well into the overweight range in men and
was in the obese range in women (Table 2). Women overall had
a worse plasma lipid profile compared to men (Table 2). Central
obesity (defined as a waist/height ratio
≥
0.5) was extremely
prevalent in both men (80%) and women (89%) (Fig. 1). Men
were more frequently current smokers (62 vs 5% of women) and
overweight (46 vs 22% of women) (
p
<
0.001 for both). Among
men with premature ACS (
<
55 years), 72 and 12% reported
current smoking and ex-smoking, respectively (Table 3).
Women had a higher frequency of most other traditional
risk factors, including type 2 diabetes (53 vs 34% of men),
Table 1. Socio-demographics and clinical characteristics at presentation
Variables
Men (
n
=
1 256) Women (
n
=
425)
p
-value
Age, years
56 (37–73)
61 (44–80)
<
0.001
Age group (%)
<
55 years
46
28
<
0.001
55–64 years
36
39
≥
65 years
18
33
Education (%)
None
7
26
<
0.001
Primary school
17
25
Secondary school
30
27
University/college
48
22
Married (%)
92
73
<
0.001
Previous AMI (%)
21
17
NS
History of stable angina (%)
26
30
NS
Presenting symptoms (%)
Chest pain
96
93
0.003
Dyspnoea
48
58
<
0.001
Palpitations
86
84
NS
Cardiac arrest
4
3
NS
Initial diagnosis (%)
Unstable angina
22
32
<
0.001
NSTEMI
29
32
STEMI
49
36
Location, if STEMI (%)
Anterior
60
55
NS
Lateral
6
4
Inferior
34
41
Data are presented as median (5th, 95th percentile), or % within genders for all
ACS patients, unless otherwise indicated. AMI, acute myocardial infarction.
p-
values are from Mann–Whitney
U
-test for continuous variables or Pearson
χ
2
test for categorical variables. NS,
p
≥
0.1.
Table 2. Anthropometric measures and serum biochemical
parameters in the study population
Variables
Total popula-
tion
(
n
=
1 681)
Men
(
n
=
1 256)
Women
(
n
=
425)
p-
value
BMI, kg/m
2
29.8 (23.7–40.3) 29.0 (23.7–38.3) 32.9 (24.0–44.1)
<
0.001
Waist, cm
98 (72–120)
98 (73–118)
98 (72–128)
NS
Waist/height ratio 0.57 (0.43–0.72) 0.56 (0.42–0.68) 0.59 (0.44–0.80)
<
0.001
Serum biochemistry
Triglycerides,
mg/dl
160 (49–320)
155 (49–320)
170 (48–320)
0.02
(mmol/l)
1.81 (0.55–3.62) 1.75 (0.55–3.62) 1.92 (0.54–3.62)
LDL cholesterol,
mg/dl
130 (66–199)
127 (69–198)
136 (65–210)
0.03
(mmol/l)
3.37 (1.71–5.15) 3.29 (1.79–5.13) 3.52 (1.68–5.44)
HDL cholesterol,
mg/dl
40 (22–80)
40 (22–76)
41 (22–97)
0.044
(mmol/l)
1.04 (0.57–2.07) 1.04 (0.57–1.97) 1.06 (0.57–2.51)
Total cholesterol,
mg/dl
198 (131–290) 197 (130–285) 200 (137–297)
0.023
(mmol/l)
5.13 (3.39–7.51) 5.10 (3.37–7.38) 5.18 (3.55–7.69)
HbA
1c
, %
6.0 (4.8–10.0)
6.0 (4.8–9.7)
7.0 (4.8–10.5)
<
0.001
Data are presented as median (5th, 95th percentile) and groups are compared with
Mann–Whitney
U-
test
.
NS,
p
≥
0.1.
BMI, body mass index; LDL, low-density lipoprotein; HDL, high-density lipopro-
tein.